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1.
  • Andersson, Kristin, 1976, et al. (författare)
  • Restarting manufacturing systems; restart states and restartability
  • 2010
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 7:3, s. 486-499
  • Tidskriftsartikel (refereegranskat)abstract
    • A method for restart after an error in a manufacturing system is introduced. The method is able to restart systems even after nonforeseen errors that cannot be planned for, and the online part of the restart method does not require use of more powerful computers than a standard Programmable Logic Controller. It is shown what properties the control function must have to ensure that there is at least one restart state for each controller state. Sufficient conditions to guarantee the possibility to restart a system regardless of where an error occurs are given, along with indications on how the system could otherwise be rebuilt to be restartable.
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2.
  • Bengtsson, Kristofer, 1979, et al. (författare)
  • Flexible Specification of Operation Behavior Using Multiple Projections
  • 2014
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 11:2, s. 504 - 515
  • Tidskriftsartikel (refereegranskat)abstract
    • The execution behavior of a system or a product can often be specified by a set of operations (sometimes called tasks, actions or activities). The process to specify these operations seems to be a real challenge in various situations, for example when designing automation systems or keeping track of the work at an emergency department. To be flexible during design and development, is about coping with uncertainty. However, in practice, specifying operation behavior is often quite inflexible because every possible execution route is explicitly defined. This approach is sometimes refereed to as point-based engineering, which is characterized by the early selection and approval of a single "best" specific solution. This approach can result in neither a robust nor a flexible design process with many rework iterations.
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3.
  • Bengtsson, Kristofer, 1979, et al. (författare)
  • Sequence Planning Using Multiple and Coordinated Sequences of Operations
  • 2012
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 9:2, s. 308-319
  • Tidskriftsartikel (refereegranskat)abstract
    • The sequential behavior of a manufacturing system results from several constraints introduced during the product, manufacturing, and control logic development. This paper proposes methods and algorithms for automatically representing and visualizing this behavior from various perspectives throughout the development process. A new sequence planning approach is introduced that uses self-contained operations to model the activities and execution constraints. These operations can be represented and visualized from multiple perspectives using a graphical and formal language called Sequences of Operations (SOPs). The operations in a manufacturing system are related to each other in various ways, due to execution constraints expressed by operation pre- and post-conditions. These operation relations include parallel, sequence, arbitrary order, alternative, and hierarchy relations. Based on the SOP language, these relations are identified and visualized in various SOPs and sequences. A software tool, Sequence Planner, has been developed, for organizing the operations into SOPs that visualize only relevant operations and relations. Note to Practitioners-This paper proposes methods and algorithms for a new sequence planning approach in which sequences are automatically created based on the relations among operations instead of having to be manually constructed. Using various views, the sequences of operations related to, for example, part flow, robot operations, and operator tasks, can be visualized. The use of various views helps the user better understand the relations between cell control and mechanical design, and between product design and total system behavior.
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4.
  • Berglund, Tomas, et al. (författare)
  • Planning smooth and obstacle-avoiding b-spline paths for autonomous mining vehicles
  • 2010
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1545-5955 .- 1558-3783. ; 7:1, s. 167-172
  • Tidskriftsartikel (refereegranskat)abstract
    • We study the problem of automatic generation of smooth and obstacle-avoiding planar paths for efficient guidance of autonomous mining vehicles. Fast traversal of a path is of special interest. We consider four-wheel four-gear articulated vehicles and assume that we have an a priori knowledge of the mine wall environment in the form of polygonal chains. Computing quartic uniform B-spline curves, minimizing curvature variation, staying at least at a proposed safety margin distance from the mine walls, we plan high speed paths.
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5.
  • Bi, Z. M., et al. (författare)
  • Energy Modeling of Machine Tools for Optimization of Machine Setups
  • 2012
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - New York : IEEE Robotics and Automation Society. - 1545-5955 .- 1558-3783. ; 9:3, s. 607-613
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, a new energy model is developed based on the kinematic and dynamic behaviors of a chosen machine tool. One significant benefit of the developed energy model is their inherited relationship to the design variables involved in the manufacturing processes. Without radical changes of the machine tool’s structure, the proposed model can be readily applied to optimize process parameters to reduce energy consumption. A new parallel kinematic machine Exechon is used as a case study to demonstrate the modeling procedure. The derived energy model is then used for simulation of drilling operations on aircraft components to verify its feasibility. Simulation results indicate that the developed energy model has led to an optimized machine setup which only consumes less than one-third of the energy of an average machine setup over the workspace. This approach can be extended and applied to other machines to establish their energy models for green and sustainable manufacturing.
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6.
  • Black, Geoff, et al. (författare)
  • Intelligent component-based automation of baggage handling systems with IEC 61499
  • 2010
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1545-5955 .- 1558-3783. ; 7:2, s. 337-351
  • Tidskriftsartikel (refereegranskat)abstract
    • Airport baggage handling is a field of automation systems that is currently dependent on centralized control systems and conventional automation programming techniques. In this and other areas of manufacturing and materials handling, these legacy automation technologies are increasingly limiting for the growing demand for systems that are reconfigurable, fault tolerant, and easy to maintain. IEC 61499 Function Blocks is an emerging architectural framework for the design of distributed industrial automation systems and their reusable components. A number of architectures have been suggested for multiagent and holonic control systems that incorporate function blocks. This paper presents a multiagent control approach for a baggage handling system (BHS) using IEC 61499 Function Blocks. In particular, it focuses on demonstrating a decentralized control system that is scalable, reconfigurable, and fault tolerant. The design follows the automation object approach, and produces a function block component representing a single section of conveyor. In accordance with holonic principles, this component is autonomous and collaborative, such that the structure and the behavior of a BHS can be entirely defined by the interconnection of these components within the function block design environment. Simulation is used to demonstrate the effectiveness of the agent-based control system and a utility is presented for real-time viewing of these systems. Tests on a physical conveyor test system demonstrated deployment to embedded control hardware.
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7.
  • Civera, Javier, et al. (författare)
  • Special Issue on Cloud Robotics and Automation
  • 2015
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : IEEE Press. - 1545-5955 .- 1558-3783. ; 12:2, s. 396-397
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • The articles in this special section focus on the use of cloud computing in the robotics industry. The Internet and the availability of vast computational resources, ever-growing data and storage capacity have the potential to define a new paradigm for robotics and automation. An intelligent system connected to the Internet can expand its onboard local data, computation and sensors with huge data repositories from similar and very different domains, massive parallel computation from server farms and sensor/actuator streams from other robots and automata. It is the potential and also the research challenges of the field that become the focus on this special section. The goal is to group together and to show the state-of-the-art of this newly emerged field, identify the relevant advances and topics, point out the current lines of research and potential applications, and discuss the main research challenges and future work directions.
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8.
  • Cronrath, Constantin, 1990, et al. (författare)
  • How Useful is Learning in Mitigating Mismatch Between Digital Twins and Physical Systems?
  • 2024
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 21:1, s. 758-770
  • Tidskriftsartikel (refereegranskat)abstract
    • In the control of complex systems, we observe two diametrical trends: model-based control derived from digital twins, and model-free control through AI. There are also attempts to bridge the gap between the two by incorporating learning-based AI algorithms into digital twins to mitigate mismatches between the digital twin model and the physical system. One of the most straightforward approaches to this is direct input adaptation. In this paper, we ask whether it is useful to employ a generic learning algorithm in such a setting, and our conclusion is "not very". We denote an algorithm to be more useful than another algorithm based on three aspects: 1) it requires fewer data samples to reach a desired minimal performance, 2) it achieves better performance for a reasonable number of data samples, and 3) it accumulates less regret. In our evaluation, we randomly sample problems from an industrially relevant geometry assurance context and measure the aforementioned performance indicators of 16 different algorithms. Our conclusion is that blackbox optimization algorithms, designed to leverage specific properties of the problem, generally perform better than generic learning algorithms, once again finding that "there is no free lunch".
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9.
  • Cui, Shaohua, et al. (författare)
  • Temporal Finite-Time Adaptation in Controlling Quantized Nonlinear Systems Amidst Time-Varying Output Constraints
  • 2024
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; In Press
  • Tidskriftsartikel (refereegranskat)abstract
    • Using the backstepping technique, this paper formulates innovative adaptive finite-time stabilizing controllers for uncertain nonlinear systems featuring nonuniform input quantization and asymmetric, time-varying output constraints. These novel controllers leverage the consistent characteristics of both hysteresis quantizers and logarithmic quantizers. Quantization errors, when consistent, become unbounded and contingent on control input, rendering them incompatible with the growth conditions of nonlinear systems. Consequently, the developed adaptive controllers eliminate the reliance on growth conditions, effectively addressing the impact of unbounded quantization errors on finite-time stability. This adaptability allows the controllers to function effectively with systems employing either hysteresis quantizers or logarithmic quantizers. The paper establishes the convergence of these controllers through the finite-time Lyapunov stability theorem. It also provides a comprehensive guideline for tuning settling time, enabling fine-grained control over finite-time convergence and adjustable tracking error performance. Additionally, the controllers rigorously maintain system output within predefined limits. Their effectiveness and low computational burden are demonstrated through three comparative numerical simulations and a practical simulation in collision-free trajectory tracking control of an autonomous vehicle platoon using the vehicle motion software CarSim. These simulations confirm the advanced performance of the adaptive controllers. Note to Practitioners—This paper introduces an innovative approach to control uncertain nonlinear systems encountering intricate input quantization and output constraints. Employing the sophisticated backstepping technique, the authors present adaptive finite-time-stabilizing controllers engineered to address nonuniform input quantization and asymmetric, time-varying output restrictions. What distinguishes these controllers is their reliance on the consistent behavior exhibited by hysteresis and logarithmic quantizers. This unique feature equips them to effectively counteract unbounded quantization errors influenced by control input. Most notably, these controllers eliminate the conventional growth conditions typically demanded by nonlinear systems. As a result, they extend their applicability to a broad spectrum of systems employing either hysteresis or logarithmic quantizers. The research also provides practitioners with a valuable guideline for precisely adjusting settling time. This enables the attainment of desired convergence rates while permitting adaptable tracking error performance. Additionally, these controllers guarantee that the system’s output adheres to predefined limits. The practical significance of this study is highlighted through three comparative numerical simulations and a real-world application simulation. This real-world simulation involves collision-free trajectory tracking control of an autonomous vehicle platoon, executed using the vehicle motion software CarSim. These simulations unequivocally demonstrate the effectiveness and low computational burden of the developed controllers, thereby establishing them as a valuable resource for practitioners facing complex control challenges in various domains.
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10.
  • Dai, Wenbin, et al. (författare)
  • Redesign distributed PLC control systems using IEC 61499 function blocks
  • 2012
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1545-5955 .- 1558-3783. ; 9:2, s. 390-401
  • Tidskriftsartikel (refereegranskat)abstract
    • The IEC 61499 Function Block architecture is considered as the next generation of programmable control technology promoting distributed control in automation. In this paper, the redesign methodologies from the PLC control to the event-driven architecture of IEC 61499 function blocks are proposed. A general set of translation steps and mapping rules for redesigning applications from IEC 61131-3 PLC to IEC 61499 Function Blocks is provided. Three different redesign approaches are proposed: object-oriented conversion approach, object-oriented reuse approach, and class-oriented approach. These approaches are to be applied for different design styles of the source PLC code. The data handling efficiency of all approaches is investigated. An airport baggage handling system is chosen as the case study for the redesign process. The rules and limitations are summarized and guidelines for the redesign process are provided.
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11.
  • Ebadat, Afrooz, et al. (författare)
  • Regularized Deconvolution-Based Approaches for Estimating Room Occupancies
  • 2015
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 1545-5955 .- 1558-3783. ; 12:4, s. 1157-1168
  • Tidskriftsartikel (refereegranskat)abstract
    • We address the problem of estimating the number of people in a room using information available in standard HVAC systems. We propose an estimation scheme based on two phases. In the first phase, we assume the availability of pilot data and identify a model for the dynamic relations occurring between occupancy levels, CO2 concentration and room temperature. In the second phase, we make use of the identified model to formulate the occupancy estimation task as a deconvolution problem. In particular, we aim at obtaining an estimated occupancy pattern by trading off between adherence to the current measurements and regularity of the pattern. To achieve this goal, we employ a special instance of the so-called fused lasso estimator, which promotes piecewise constant estimates by including an l(1) norm-dependent term in the associated cost function. We extend the proposed estimator to include different sources of information, such as actuation of the ventilation system and door opening/closing events. We also provide conditions under which the occupancy estimator provides correct estimates within a guaranteed probability. We test the estimator running experiments on a real testbed, in order to compare it with other occupancy estimation techniques and assess the value of having additional information sources.
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12.
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13.
  • Falkman, Petter, 1972, et al. (författare)
  • Generation of STEP AP214 models from discrete event systems for process planning and control
  • 2008
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1545-5955 .- 1558-3783. ; 5:1, s. 113-126
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this paper is to show how the international standard STEP-AP214 can be used for communication and storing of process specifications. Even though there are several software tools available for the generation of both product and resource information systems, there is still a lack of tools related to the STEP standard for producing process information, e.g., sequence of operations and system capabilities for resource allocation. Therefore, such a tool is suggested, which makes use of a high-level language for discrete-event systems based on process algebra and Petri nets. This language, called process algebra Petri net), has been developed in accordance with the process relations defined in STEP-AP214. More specifically, it is shown how process specifications created with the PPN tool can be mapped to the STEP AP-214 format. Note to Practioners-Rapidly changing market needs is making demands on flexibility and ability to shorten lead times. Standards for exchanging information, as well as formal methods for automatic development of programmable controller code have been important research topics for many years. There are a lot of software tools available for the generation of both product- and resource information, but there is still a lack of tools for producing process information. Moreover, the connection between information exchange standards and such tools is absent, which makes the development of programmable controller code an isolated activity. This activity is often time consuming and performed in an ad hoc manner resulting in unnecessary production delay. The aim of this paper is to show how the international standard STEP-AP214 (a standard for exchange of product-, process-, and resource related information) can be used for communicating and storing process specifications. In order to achieve this, a tool which makes use of a formal high-level language is suggested. This tool can be used for automatic control generation and has been developed in accordance with the process relations defined in STEP-AP214. A further aim is to shown how the mentioned tool can be used to specify complex systems in a compact, yet highly readable manner, which is a crucial incentive for industry to use formal methods. The presented method will guarantee-that expected information is delivered quickly and without errors caused by the human factor, something that is very important in our ambition to achieve shortened lead times. The quick information exchange also makes it possible to perform simulation, supervisor synthesis, and verification early in the development phase. This is a first attempt at using a formal language for creating a tool that can automatically generate specifications in accordance with the international STEP-standard.
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14.
  • Fan, J., et al. (författare)
  • An Integrated Hand-Object Dense Pose Estimation Approach With Explicit Occlusion Awareness for Human-Robot Collaborative Disassembly
  • 2024
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 1545-5955 .- 1558-3783. ; 21:1, s. 147-156
  • Tidskriftsartikel (refereegranskat)abstract
    • Human-robot collaborative disassembly (HRCD) has gained much interest in the disassembly tasks of end-of-life products, integrating both robot’s high efficiency in repetitive works and human’s flexibility with higher cognition. Explicit human-object perceptions are significant but remain little reported in the literature for adaptive robot decision-makings, especially in the close proximity co-work with partial occlusions. Aiming to bridge this gap, this study proposes a vision-based 3D dense hand-object pose estimation approach for HRCD. First, a mask-guided attentive module is proposed to better attend to hand and object areas, respectively. Meanwhile, explicit consideration of the occluded area in the input image is introduced to mitigate the performance degradation caused by visual occlusion, which is inevitable during HRCD hand-object interactions. In addition, a 3D hand-object pose dataset is collected for a lithium-ion battery disassembly scenario in the lab environment with comparative experiments carried out, to demonstrate the effectiveness of the proposed method. —This work aims to overcome the challenge of joint hand-object pose estimation in a human-robot collaborative disassembly scenario, of which can also be applied to many other close-range human-robot/machine collaboration cases with practical values. The ability to accurately perceive the pose of the human hand and workpiece under partial occlusion is crucial for the collaborative robot to successfully carry out co-manipulation with human operators. This paper proposes an approach that can jointly estimate the 3D pose of the hand and object in an integrated model. An explicit prediction of the occlusion area is then introduced as a regularization term during model training. This can make the model more robust to partial occlusion between the hand and object. The comparative experiments suggest that the proposed approach outperforms many existing hand-object estimation ones. Nevertheless, the dependency on manually labeled training data can limit its application. In the future, we will consider semi-supervised or unsupervised training to address this issue and achieve faster adaptation to different industrial scenarios. 
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15.
  • Fang, Jingzhong, et al. (författare)
  • A New Particle Swarm Optimization Algorithm for Outlier Detection : Industrial Data Clustering inWire Arc Additive Manufacturing
  • 2023
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1545-5955 .- 1558-3783. ; 21:2, s. 1244-1257
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, a novel outlier detection method is proposed for industrial data analysis based on the fuzzy C-means (FCM) algorithm. An adaptive switching randomly perturbed particle swarm optimization algorithm (ASRPPSO) is put forward to optimize the initial cluster centroids of the FCM algorithm. The superiority of the proposed ASRPPSO is demonstrated over five existing PSO algorithms on a series of benchmark functions. To illustrate its application potential, the proposed ASRPPSO-based FCM algorithm is exploited in the outlier detection problem for analyzing the real-world industrial data collected from a wire arc additive manufacturing pilot line in Sweden. Experimental results demonstrate that the proposed ASRPPSO-based FCM algorithm out performs the standard FCM algorithm in detecting outliers of real-world industrial data.Note to PractitionersElectric arc (which is governed by the current and arc voltage) plays a significant role in monitoring the operating status of the wire arc additive manufacturing (WAAM) process. The nominal periodic current and voltage may occasionally change abruptly due to anomalies (such asarc instability, unstable metal transfer, geometrical deviations, and surface contaminations), which would affect the quality of the fabricated component. This paper focuses on detecting possible anomalies by analyzing the current and voltage during the WAAM process. A novel clustering-based outlier detection method is proposed for anomaly detection where abnormal and normal instances are categorized into two separate clusters. A new particle swarm optimization algorithm is put forward to optimize the initial cluster centroid so as to improve the detection accuracy. The proposed outlier detection method is applied to real-world data collected from a WAAM pilot line for detecting abnormal instances. Experimental results demonstrate the effectiveness of the proposed outlier detection method. The proposed outlier detection method can be applied to other industrial applications including electrical engineering, mechanical engineering and medical engineering. In the future, we aim to develop an online outlier detection system based on the proposed method for real-time for anomaly detection and defect prediction.
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16.
  • Farooqui, Ashfaq, et al. (författare)
  • On Active Learning for Supervisor Synthesis
  • 2024
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : Institute of Electrical and Electronics Engineers Inc.. - 1545-5955 .- 1558-3783. ; 21, s. 78-
  • Tidskriftsartikel (refereegranskat)abstract
    • Supervisory control theory provides an approach to synthesize supervisors for cyber-physical systems using a model of the uncontrolled plant and its specifications. These supervisors can help guarantee the correctness of the closed-loop controlled system. However, access to plant models is a bottleneck for many industries, as manually developing these models is an error-prone and time-consuming process. An approach to obtaining a supervisor in the absence of plant models would help industrial adoption of supervisory control techniques. This paper presents, an algorithm to learn a controllable supervisor in the absence of plant models. It does so by actively interacting with a simulation of the plant by means of queries. If the obtained supervisor is blocking, existing synthesis techniques are employed to prune the blocking supervisor and obtain the controllable and non-blocking supervisor. Additionally, this paper presents an approach to interface the with a PLC to learn supervisors in a virtual commissioning setting. This approach is demonstrated by learning a supervisor of the well-known example simulated in Xcelgo Experior and controlled using a PLC. interacts with the PLC and learns a controllable supervisor for the simulated system. Note to Practitioners—Ensuring the correctness of automated systems is crucial. Supervisory control theory proposes techniques to help build control solutions that have certain correctness guarantees. These techniques rely on a model of the system. However, such models are typically unavailable and hard to create. Active learning is a promising technique to learn models by interacting with the system to be learned. This paper aims to integrate active learning and supervisory control such that the manual step of creating models is no longer needed, thus, allowing the use of supervisory control techniques in the absence of models. The proposed approach is implemented in a tool and demonstrated using a case study. 
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17.
  • Fei, Zhennan, 1984, et al. (författare)
  • A BDD-Based Approach for Designing Maximally Permissive Deadlock Avoidance Policies for Complex Resource Allocation Systems
  • 2015
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 12:3, s. 990-1006
  • Tidskriftsartikel (refereegranskat)abstract
    • In order to develop a computationally efficient implementation of the maximally permissive deadlock avoidance policy (DAP) for complex resource allocation systems (RAS), a recent approach focuses on the identification of a set of critical states of the underlying RAS state-space, referred to as minimal boundary unsafe states. The availability of this information enables an expedient one-step-lookahead scheme that prevents the RAS from reaching outside its safe region. The work presented in this paper seeks to develop a symbolic approach, based on binary decision diagrams (BDDs), for efficiently retrieving the (minimal) boundary unsafe states from the underlying RAS state-space. The presented results clearly demonstrate that symbolic computation enables the deployment of the maximally permissive DAP for complex RAS with very large structure and state-spaces with limited time and memory requirements. Furthermore, the involved computational costs are substantially reduced through the pertinent exploitation of the special structure that exists in the considered problem.
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18.
  • Gleeson, Daniel, 1988, et al. (författare)
  • Generating Optimized Trajectories for Robotic Spray Painting
  • 2022
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 19:3, s. 1380-1391
  • Tidskriftsartikel (refereegranskat)abstract
    • In the manufacturing industry, spray painting is often an important part of the manufacturing process. Especially in the automotive industry, the perceived quality of the final product is closely linked to the exactness and smoothness of the painting process. For complex products or low batch size production, manual spray painting is often used. But in large scale production with a high degree of automation, the painting is usually performed by industrial robots. There is a need to improve and simplify the generation of robot trajectories used in industrial paint booths. A novel method for spray paint optimization is presented, which can be used to smooth out a generated initial trajectory and minimize paint thickness deviations from a target thickness. The smoothed out trajectory is found by solving, using an interior point solver, a continuous non-linear optimization problem. A two-dimensional reference function of the applied paint thickness is selected by fitting a spline function to experimental data. This applicator footprint profile is then projected to the geometry and used as a paint deposition model. After generating an initial trajectory, the position and duration of each trajectory segment are used as optimization variables. The primary goal of the optimization is to obtain a paint applicator trajectory, which would closely match a target paint thickness when executed. The algorithm has been shown to produce satisfactory results on both a simple 2-dimensional test example, and a non-trivial industrial case of painting a tractor fender. The resulting trajectory is also proven feasible to be executed by an industrial robot.
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19.
  • Guellouz, Safa, et al. (författare)
  • Designing Efficient Reconfigurable Control Systems Using IEC61499 and Symbolic Model Checking
  • 2019
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : IEEE. - 1545-5955 .- 1558-3783. ; 16:3, s. 1110-1124
  • Tidskriftsartikel (refereegranskat)abstract
    • IEC 61499 provides a standardized approach for the development of distributed control systems. The standard introduces a component architecture, based on function blocks that are event-triggered components processing data and signals. However, it gives only limited support for the design of reconfigurable architectures. In particular, handling of several reconfiguration scenarios is quite heavy on this level since a scenario changes the execution model of the system due to requirements. To this end, a new IEC 61499-based model named reconfigurable function blocks (RFBs) is proposed. An RFB processes the reconfiguration events and switches directly to the suitable configuration using a hierarchical state machine model. The latter represents the reconfiguration model which reacts on changes in the environment in order to find an adequate reconfiguration scenario to be executed. Each scenario presents a particular sequence of algorithms, encapsulated in another execution control chart slave which represents the control model of an RFB. This hierarchy simplifies the design and separates the reconfiguration logic from control models. To verify its correctness and alleviate its state space explosion problem in model checking, this paper translates an RFB system automatically into a generalized model of reconfigurable timed net condition/event systems (GR-TNCES), a Petri net class that preserves the semantics of an RFB system. In this paper, along with verification of deterministic properties, we also propose to quantify and analyze some probabilistic properties. As a case study, we consider a smart-grid system, interpreting permanent faults in it as reconfiguration events, and we characterize them with the expected occurrence probability and the corresponding repair time. A tool chain ZiZo is developed to support the proposed approach.
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20.
  • Guo, Meng, 1988-, et al. (författare)
  • Task and Motion Coordination for Heterogeneous Multiagent Systems With Loosely Coupled Local Tasks
  • 2017
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : IEEE. - 1545-5955 .- 1558-3783. ; 14:2, s. 797-808
  • Tidskriftsartikel (refereegranskat)abstract
    • We consider a multiagent system that consists of heterogeneous groups of homogeneous agents. Instead of defining a global task for the whole team, each agent is assigned a local task as syntactically cosafe linear temporal logic formulas that specify both motion and action requirements. Interagent dependence is introduced by collaborative actions, of which the execution requires multiple agents' collaboration. To ensure the satisfaction of all local tasks without central coordination, we propose a bottom-up motion and task coordination strategy that contains an off-line initial plan synthesis and an online coordination scheme based on real-time exchange of request and reply messages. It facilitates not only the collaboration among heterogeneous agents but also the task swapping between homogeneous agents to reduce the total execution cost. It is distributed as any decision is made locally by each agent based on local computation and communication within neighboring agents. It is scalable and resilient to agent failures as the dependence is formed and removed dynamically based on agent capabilities and their plan execution status, instead of preassigned agent identities. The overall scheme is demonstrated by a simulated scenario of 20 agents with loosely coupled local tasks.
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21.
  • Hagebring, Fredrik, 1985, et al. (författare)
  • On Optimization of Automation Systems : Integrating Modular Learning and Optimization
  • 2022
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : Institute of Electrical and Electronics Engineers Inc.. - 1545-5955 .- 1558-3783. ; 19:3, s. 1662-1674
  • Tidskriftsartikel (refereegranskat)abstract
    • Compositional Optimization (CompOpt) was recently proposed for optimization of discrete-event systems of systems. A modular optimization model allows CompOpt to divide the optimization into separate sub-problems, mitigating the state space explosion problem. This paper presents the Modular Optimization Learner (MOL), a method that interacts with a simulation of a system to automatically learn these modular optimization models. MOL uses a modular learning that takes as input a hypothesis structure of the system and uses the provided structural information to split the acquired learning into a set of modules, and to prune parts of the search space. Experiments show that modular learning reduces the state space by many orders of magnitude compared to a monolithic learning, which enables learning of much larger systems. Furthermore, an integrated greedy search heuristic allows MOL to remove many sub-optimal paths in the individual modules, speeding up the subsequent optimization.
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22.
  • Heshmati Alamdari, Shahabodin, et al. (författare)
  • Robust Trajectory Tracking Control for Underactuated Autonomous Underwater Vehicles in Uncertain Environments
  • 2021
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 1545-5955 .- 1558-3783. ; 18:3, s. 1288-1301
  • Tidskriftsartikel (refereegranskat)abstract
    • This article addresses the tracking control problem of 3-D trajectories for underactuated underwater robotic vehicles operating in a constrained workspace including obstacles. More specifically, a robust nonlinear model predictive control (NMPC) scheme is presented for the case of underactuated autonomous underwater vehicles (AUVs) (i.e., unicycle-like vehicles actuated only in the surge, heave, and yaw). The purpose of the controller is to steer the unicycle-like AUV to the desired trajectory with guaranteed input and state constraints (e.g., obstacles, predefined vehicle velocity bounds, and thruster saturations) inside a partially known and dynamic environment where the knowledge of the operating workspace is constantly updated via the vehicle's onboard sensors. In particular, considering the sensing range of the vehicle, obstacle avoidance with any of the detected obstacles is guaranteed by the online generation of a collision-free trajectory tracking path, despite the model dynamic uncertainties and the presence of external disturbances representing ocean currents and waves. Finally, realistic simulation studies verify the performance and efficiency of the proposed framework. Note to Practitioners-This article was motivated by the problem of robust trajectory tracking for an autonomous underwater vehicle (AUV) operating in an uncertain environment where the knowledge of the operating workspace (e.g., obstacle positions) is constantly updated online via the vehicle's onboard sensors (e.g., multibeam imaging sonars and laser-based vision systems). In addition, there may be other system limitations (e.g., thruster saturation limits) and other operational constraints, induced by the need of various common underwater tasks (e.g., a predefined vehicle speed limit for inspecting the seabed, and mosaicking), where it should also be considered into the control strategy. However, based on the existing trajectory tracking control approaches for underwater robotics, there is a lack of an autonomous control scheme that provides a complete and credible control strategy that takes the aforementioned issues into consideration. Based on this, we present a reliable control strategy that takes into account the aforementioned issues, along with dynamic uncertainties of the model and the presence of ocean currents. In future research, we will extend the proposed methodology for multiple AUV performing collaborative inspection tasks in an uncertain environment.
  •  
23.
  • Kaheni, Kaheni, et al. (författare)
  • Resilient and Privacy-Preserving Multi-Agent Optimization and Control of a Network of Battery Energy Storage Systems Under Attack
  • 2023
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1545-5955 .- 1558-3783.
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper deals with resilient and privacy-preserving control to optimize the daily operation costs of networked Battery Energy Storage Systems (BESS) in a multi-agent network vulnerable to various types of cyber-attacks. First, we formulate the optimization problem by defining the objective function and the local and coupling constraints. Next, we introduce a novel resilient decentralized control and optimization algorithm that can mitigate the effects of cyber-attacks, specifically false data injection attacks and hijacking, to enhance the network's resilience. The proposed method is based on filtering out outlier Lagrange multipliers in a suitable dual problem. Our proposed algorithm has two main advantages compared to the existing literature. Firstly, it can solve problems where the coupling constraint is not restricted to the average or a function of the average of decision variables. Secondly, our algorithm extends the well-known dual decomposition and Lagrange multiplier method to the decentralized control problem of BESSs. In the proposed algorithm presented in this paper, only the data relevant to the dual problem is exchanged among the agents. Noticing that the data of the dual problem does not contain any private information, mitigating privacy concerns associated with our proposed algorithm. We formally prove the convergence of our algorithm to a feasible and sub-optimal solution. Additionally, simulations demonstrate the effectiveness of our results.Note to Practitioners-Optimal coordinated control of BESSs increases the power system's reliability and reduces costs. With the expansion of the use of small-scale BESSs in household customers, it is possible to considerably increase the free capacity of power networks by optimally controlling these small BESSs. The methods published so far to solve such problems either share the private information of each BESS or are not resilient to failures or false data injection due to cyber-attacks. Therefore, these approaches are not favored in practical applications. Considering this practical motivation, in this paper, we present a decentralized algorithm to control a large set of BESSs in a platform vulnerable to various types of cyber-attacks without compromising privacy.
  •  
24.
  • Lennartson, Bengt, 1956-, et al. (författare)
  • Modeling and Optimization of Hybrid Systems for the Tweeting Factory
  • 2016
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1545-5955 .- 1558-3783. ; 13:1, s. 195-205
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, a predicate transition model for discrete-event systems is generalized to include continuous dynamics, and the result is a modular hybrid predicate transition model. Based on this model, a hybrid Petri net including explicit differential equations and shared variables is also proposed. It is then shown how this hybrid Petri net model can be optimized based on a simple and robust nonlinear programming formulation. The procedure only assumes that desired sampled paths for a number of interacting moving devices are given, while originally equidistant time instances are adjusted to minimize a given criterion. This optimization of hybrid systems is also applied to a real robot station with interacting devices, which results in about 30% reduction in energy consumption. Moreover, a flexible online and event-based information architecture called the Tweeting Factory is proposed. Simple messages (tweets) from all kinds of equipment are combined into high-level knowledge, and it is demonstrated how this information architecture can be used to support optimization of robot stations.
  •  
25.
  • Lennartson, Bengt, 1956, et al. (författare)
  • Sequence Planning for Integrated Product, Process and Automation Design
  • 2010
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 7:4, s. 791-802
  • Tidskriftsartikel (refereegranskat)abstract
    • In order to obtain a unified information flow from early product design to final production, an integrated framework for product, process and automation design is presented. The framework is based on sequences of operations and includes a formal relation between product properties and process operations. This relation includes liaisons (interfaces) and precedence relations, where the precedence relations generate preconditions for the related process operations. From this information a set of sequences of operations (SOPs) is generated. A formal graphical language for hierarchical operations and SOPs is then introduced and defined based on automata extended with variables. Since the operations are self-contained they can be grouped and viewed from different angles, e. g., from a product or a resource perspective. These multiple views increase the interoperability between different engineering disciplines. A case study is performed on a car manufacturing cell, where the suggested modeling framework is shown to give comprehensible SOPs. Note to Practitioners-When designing an automation system, an important challenge is to specify in what sequence the different tasks, or operations, should be executed. This has become a problematic bottleneck in the automotive industry, especially for body-in-white manufacturing. The rising needs on manufacturing flexibility increases the complexity of the entire manufacturing system, as well as its control function, the sequence of operations. This paper proposes a new sequence planning approach, where sequences are viewed based on the relations among operations instead of manually constructing the sequence. By the use of different views the sequence of operations related to, e. g., the part flow, robot operations or operator tasks can be visualized. Different views help the user to easier understand the relation between different parts and components, as well as the total system behavior.
  •  
26.
  • Lennartson, Bengt, 1956, et al. (författare)
  • Supervisory Control for State-Vector Transition Models—A Unified Approach
  • 2014
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 11:1, s. 33-47
  • Tidskriftsartikel (refereegranskat)abstract
    • A generic state-vector transition (SVT) model is suggested, including a flexible synchronous composition involving both shared variables and events. This model is analyzed, focusing on properties that are important for supervisor synthesis. A synthesis procedure is then developed for the SVT model, where supervisor guards are generated that guarantee a controllable, nonblocking and maximally permissive supervisor. Novel conditions are introduced, such that more flexible specifications can be applied than earlier suggested for related models. Since the SVT model includes automata and (colored) Petri nets, optionally extended with variables, guards and actions, as special cases, the suggested synthesis approach unifies supervisor synthesis for the main discrete event model classes. Finally, the SVT model is naturally represented and efficiently computed based on binary decision diagrams, and the resulting supervisor guards are easily implemented in industrial control systems.
  •  
27.
  • Li, J. S., et al. (författare)
  • Automation in Green Manufacturing
  • 2013
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 1558-3783 .- 1545-5955. ; 10:1, s. 1-4
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
  •  
28.
  • Liu, Xu, et al. (författare)
  • Combining Dynamic Machining Feature With Function Blocks for Adaptive Machining
  • 2016
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 1545-5955 .- 1558-3783. ; 13:2, s. 828-841
  • Tidskriftsartikel (refereegranskat)abstract
    • Feature-based technologies are widely researched for manufacturing automation. However, in current feature models, features once defined remain constant throughout the whole manufacturing lifecycle. This static feature model is inflexible to support adaptive machining when facing frequent changes to manufacturing resources. This paper presents a new machining feature concept that facilitates responsive changes to the dynamics of machining features in 2.5/3D machining. Basic geometry information for feature construction of complex parts with various intersecting features is represented as a set of meta machining features (MMF). Optimum feature definition is generated adaptively by choosing optimum merging strategies of MMFs according to the capabilities of the selected machine tool, cutter, and cutting parameters. A composite function block for dynamic machining feature modelling is designed with Basic Machining Feature Function Block, Meta Machining Feature Extraction Function Block and Feature Interpreter Function Block. Once changes of the selected machining resources occur, they are informed as input events and machining features are then updated automatically and adaptively based on the event-driven model of function blocks. An example is provided to demonstrate the feasibility and benefits of the developed methodology.
  •  
29.
  • Ljungkrantz, Oscar, 1978, et al. (författare)
  • Formal Specification and Verification of Industrial Control Logic Components
  • 2010
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 7:3, s. 538-548
  • Tidskriftsartikel (refereegranskat)abstract
    • Component-based programming frameworks for industrial control logic development promise to shorten development and modification times, and to reduce programming errors. To get these benefits, it is, however, important that the components are specified and verified to work properly. This work introduces Reusable Automation Components (RACs), which contain not only the implementation details but also a formal specification defining the correct use and behaviour of the component. This formal specification uses temporal logic to describe time-related properties and has a special structure developed to meet industrial control needs. The RAC can be formally verified, to determine whether the implementation fulfils the specification or not. A RAC prototype development tool has been developed to demonstrate this capability. The main difference between the RAC and other frameworks for formal verification of control logic is the specification modeling. In RAC, not only the implementation but also the specification is based on the structure and languages of conventional control logic, aiming at being easy to comprehend for control logic engineers. Several industrial examples are discussed in this paper, showing the benefits and potential of the framework. Note to Practitioners-Today robots and machines in automated production are usually controlled by a special industrial computer called Programmable Logic Controller (PLC). Although PLC programs are widely used in manufacturing industry, current programs tend to be difficult and time-consuming to modify when needed. They are also often tested to work first on the real equipment, which may be expensive since the regular production is stopped for code testing and error resolving. In this work, we introduce Reusable Automation Components (RACs), to facilitate PLC program development. Reusing components may speed up the development and also reduce the number of errors, if the components are already verified to work properly before the reuse. To achieve this, the RACs can be richly specified, defining the correct use and behaviour of the components. The specification can then be used to verify, formally, whether the RAC works correctly or not, according to the specification. Formal verification uses math-based models and algorithms to automatically explore all possible behaviours of the component. The RAC can be automatically translated to a tool that performs the formal verification and shows counterexamples if the specification is not fulfilled. The specification and verification of RACs are intended to be useful for control logic engineers. Hence, the specification of the RAC is based on the structure and languages of conventional PLC programs. This paper discusses a number of industrial examples which show the applicability of the RACs. The RAC framework can be further improved, especially by developing guidelines and aid for writing the specifications.
  •  
30.
  • Mahler, Jeffrey, et al. (författare)
  • Synthesis of Energy-Bounded Planar Caging Grasps Using Persistent Homology
  • 2018
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1545-5955 .- 1558-3783. ; 15:3, s. 908-918
  • Tidskriftsartikel (refereegranskat)abstract
    • For applications such as manufacturing, caging grasps restrict object motion without requiring complete immobilization, providing a robust alternative to force-and form-closure grasps. Energy-bounded cages are a new class of caging grasps that relax the requirement of complete caging in the presence of external forces such as gravity or constant velocity pushing in the horizontal plane with Coulomb friction. We address the problem of synthesizing planar energy-bounded cages by identifying gripper and force-direction configurations that maximize the energy required for the object to escape. We present Energy-Bounded-Cage-Synthesis-2-D (EBCS-2-D), a sampling-based algorithm that uses persistent homology, a recently-developed multiscale approach for topological analysis, to efficiently compute candidate rigid configurations of obstacles that form energy-bounded cages of an object from an alpha-shape approximation to the configuration space. If a synthesized configuration has infinite escape energy then the object is completely caged. EBCS-2-D runs in O(s(3) + sn(2)) time, where s is the number of samples and n is the number of object and obstacle vertices, where typically n << s. We observe runtimes closer to O(s) for fixed n. We implement EBCS-2-D using the persistent homology algorithms toolbox and study performance on a set of seven planar objects and four gripper types. Experiments suggest that EBCS-2-D takes 2-3 min on a 6 core processor with 200 000 pose samples. We also confirm that an rapidly-exploring random tree* motion planner is unable to find escape paths with lower energy. Physical experiments on a five degree of freedom Zymark Zymate and ABB YuMi suggest that push grasps synthesized by EBCS-2-D are robust to perturbations. Data and code are available at http://berkeleyautomation.github.io/caging/.
  •  
31.
  • Mashaei, Maziar, 1973, et al. (författare)
  • Energy Reduction in a Pallet-Constrained Flow Shop through On-Off Control of Idle Machines
  • 2013
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 10:1, s. 45-56
  • Tidskriftsartikel (refereegranskat)abstract
    • For flexible manufacturing systems, there are normally some durations in which a number of machines are idle and do not process any parts. Devising a control policy to turn off the idle machines and reduce their level of energy consumption is a significant contribution towards the green manufacturing paradigm. This paper addresses the design of such a control strategy for a closed loop flow shop plant based on a one-loop pallet system. The main goal is to coordinate running of the machines and motion of pallets to gain the minimal energy consumption in idle machines, as well as to obtain the desired throughput for the plant. To fulfill this goal, first mathematical conditions, which economically characterize the on-off control for machines, are presented. Constrained to these conditions and the mathematical models describing the pallet system, a mixed integer nonlinear minimization problem with the energy monitor as the objective function is then developed. Provided that the problem computation time can be managed, the optimal control for the operation of the plant and the minimal energy consumption in the idle machines are computed. To deal with the time complexity, a linearized form of the model and a heuristic approach are introduced. These methods are applied to some examples of industrial size, and their impacts in practice are discussed and verified by using a discrete event simulation tool.
  •  
32.
  • Mashaei, Maziar, 1973, et al. (författare)
  • Sustainable and Robust Control of Cyclic Pallet Systems
  • 2013
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 10:4, s. 916-927
  • Tidskriftsartikel (refereegranskat)abstract
    • A proper control of a system to get a desired function and increase the system lifetime is a crucial step towards the sustainable paradigm. In this paper, such a control is designed for a cyclic pallet system to achieve a minimal force on its drive unit, meet safety conditions on the system chain tension force, and the momentum of pallets, and fulfill a desired production rate. The optimal values of control parameters, namely, number of pallets, conveyor velocity, and part set schedule, are obtained through solving a mixed integer linear optimization model. The objective function in the model defines the average force on the drive unit in a cycle production. In addition, the related constraints characterize the pallet system properties such as cyclic and dynamic behavior, buffer size, constant work in process, and safety specifications. This optimization model strongly suffers from the time complexity due to the binary decision variables defining the part set schedule. To reasonably handle the computation time, a heuristic search strategy based on a modified form of the weighted profile fitting algorithm is introduced. Furthermore, the robustness of the optimal control and the system design is analyzed, using worst control and worst but safe control strategies. The optimal control and the robustness analysis are applied to some case studies, and the results are evaluated and discussed.
  •  
33.
  • Miremadi, Sajed, 1983, et al. (författare)
  • Symbolic Computation of Reduced Guards in Supervisory Control
  • 2011
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 8:4, s. 754-765
  • Tidskriftsartikel (refereegranskat)abstract
    • In the supervisory control theory, a supervisor is generated based on given plant and specification models. The supervisor restricts the plant in order to fulfill the specifications. A problem that is typically encountered in industrial applications is that the resulting supervisor is not easily comprehensible for the users. To tackle this problem, we introduce an efficient method to characterize a supervisor by tractable logic conditions, referred to as guards, generated from the models. The guards express under which conditions an event is allowed to occur to fulfill the specifications. To obtain tractable guard expressions, we reduce them by exploiting the structure of the given models. In order to be able to handle complex systems efficiently, the models are symbolically represented by binary decision diagrams and all computations are performed on these data structures. The algorithms have been implemented in a supervisory control tool and applied to an industrially relevant example.
  •  
34.
  • Miremadi, Sajed, 1983, et al. (författare)
  • Symbolic Representation and Computation of Timed Discrete-Event Systems
  • 2014
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 1558-3783 .- 1545-5955. ; 11:1, s. 6-19
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, we symbolically represent timed discrete-event systems (TDES), which can be used to efficiently compute the supervisor in the supervisory control theory context. We model a TDES based on timed extended finite automata (TEFAs): an augmentation of extended finite automata (EFAs) by incorporating discrete time into the model. EFAs are ordinary automata extended with discrete variables, where conditional expressions and update functions can be attached to the transitions. The symbolic computations are based on binary decision diagrams (BDDs). We show how TEFAs can be represented by BDDs. The main feature of this approach is that the BDD-based fixed point computations are not based on tick models that have been commonly used in this area, leading to better performance in many cases. The approach has been implemented and applied to a simple case study and several large-scale benchmarks. Note to Practitioners-In today's industry, the control functions are implemented to a great extent manually by designing a candidate and verifying it towards different properties to ensure that the control function is satisfactory. Designing a control function manually makes it a tedious, error-prone and time consuming process. Another way is to do this process automatically, referred to as the synthesis method. In the synthesis method, the designers model the system's behavior and the desired properties and feed them to an algorithm that can automatically generate the control function. Supervisory Control Theory (SCT) provides a powerful framework for automatically synthesizing safe and flexible control functions, referred to as supervisors, that restrict the system only when it necessary. For large-scale systems, synthesis typically suffers of from the state space explosion problem, that is the required memory to represent the states of the system is more than the available memory. To handle real-time systems, in this paper, we also incorporate time in the theory and show how the supervisor can be efficiently computed for large-scale systems.
  •  
35.
  • Nielsen, Kristin, et al. (författare)
  • Survey on 2D Lidar Feature Extraction for Underground Mine Usage
  • 2023
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1545-5955 .- 1558-3783. ; 20:2, s. 981-994
  • Tidskriftsartikel (refereegranskat)abstract
    • Robust and highly accurate position estimation in underground mines is investigated by considering a vehicle equipped with 2D laser scanners. A survey of available methods to process data from such sensors is performed with focus on feature extraction methods. Pros and cons of the usage of different methods for the positioning application with 2D laser data are highlighted, and suitable methods are identified. Three state-of-the-art feature extraction methods are adapted to the scenario of positioning in a predefined map and the methods are evaluated through experiments conducted in a simulated underground mine environment. Results indicate that feature extraction methods perform in parity with the method of matching each ray individually to the map, and better than the point cloud scan matching method of a pure ICP, assuming a highly accurate map is available. Furthermore, experiments show that feature extraction methods more robustly handle imperfections or regions of errors in the map by automatically disregarding these regions.
  •  
36.
  • Ouedraogo, Lucien, et al. (författare)
  • Nonblocking and Safe Control of Discrete-Event Systems Modeled as Extended Finite Automata
  • 2011
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 8:3, s. 560-569
  • Tidskriftsartikel (refereegranskat)abstract
    • Extended Finite Automata (EFA), i.e., finite automata extended with variables, are a suitable modeling framework for discrete event systems owing to their compactness, resulting from the use of variables. In this paper, we propose a symbolic algorithm that efficiently synthesizes a supervisor for a plant modeled by an EFA and a specification defined by another EFA. The principle of the algorithm is to iteratively strengthen the guards of the plant EFA so that forbidden or blocking states become unreachable in the controlled plant. As a consequence of the algorithm, the controlled behavior is modeled by an EFA having the same structure as the plant EFA, having stronger guards and is shown to be maximally permissive. We illustrate our algorithm via a simple manufacturing example.
  •  
37.
  • Paridari, Kaveh, et al. (författare)
  • Robust Scheduling of Smart Appliances in Active Apartments With User Behavior Uncertainty
  • 2015
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : IEEE Press. - 1545-5955 .- 1558-3783. ; 13:1, s. 247-259
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, we propose a robust approach for scheduling of smart appliances and electrical energy storages (EESs) in active apartments with the aim of reducing both the electricity bill and the CO2 emissions. The proposed robust formulation takes the user behavior uncertainty into account so that the optimal appliances schedule is less sensitive to unpredictable changes in user preferences. The user behavior uncertainty is modeled as uncertainty in the cost function coefficients. In order to reduce the level of conservativeness of the robust solution, we introduce a parameter allowing to achieve a trade-off between the price of robustness and the protection against uncertainty. Mathematically, the robust scheduling problem is posed as a multi-objective Mixed Integer Linear Programming (MILP), which is solved by using standard algorithms. The numerical results show effectiveness of the proposed approach to increase both the electricity bill and CO2 emissions savings, in the presence of user behavior uncertainties. Mathematical insights into the robust formulation are illustrated and the sensitivity of the optimum cost in the presence of uncertainties is investigated. Although home appliances and EESs are considered in this work, we point out that the proposed scheduling framework is generally applicable to many use cases, e.g., charging and discharging of electrical vehicles in an effective way. In addition, it is applicable to various scenarios considering different uncertainty sources, different storage technologies and generic programmable electrical loads, as well as different optimization criteria.
  •  
38.
  • Raza, Shahid, et al. (författare)
  • S3K: Scalable Security With Symmetric Keys—DTLS Key Establishment for the Internet of Things
  • 2016. - 13
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : IEEE. - 1545-5955 .- 1558-3783. ; 13:3, s. 1270-1280
  • Tidskriftsartikel (refereegranskat)abstract
    • DTLS is becoming the de facto standard for communication security in the Internet of Things (IoT). In order to run the DTLS protocol, one needs to establish keys between the communicating devices. The default method of key establishment requires X.509 certificates and a Public Key Infrastructure, an approach which is often too resource consuming for small IoT devices. DTLS also supports the use of preshared keys and raw public keys. These modes are more lightweight, but they are not scalable to a large number of devices.
  •  
39.
  • Reveliotis, Spyros, et al. (författare)
  • Robust Deadlock Avoidance for Sequential Resource Allocation Systems With Resource Outages
  • 2017
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 14:4, s. 1695 - 1711
  • Tidskriftsartikel (refereegranskat)abstract
    • While the supervisory control (SC) problem of (maximally permissive) deadlock avoidance for sequential resource allocation systems (RASs) has been extensively studied in the literature, the corresponding results that are able to address potential resource outages are quite limited, both, in terms of their volume and their control capability. This paper leverages the recently developed SC theory for switched discrete event systems (s-DES) in order to provide a novel systematic treatment of this more complicated version of the RAS deadlock avoidance problem. Following the modeling paradigm of s-DES, both the operation of the considered RAS and the corresponding maximally permissive SC policy are decomposed over a number of operational modes that are defined by the running sets of the failing resources. In particular, the target supervisor must be decomposed to a set of “localized predicates,” where each predicate is associated with one of the operational modes. A significant part, and a primary contribution, of this paper concerns the development of these localized predicates that will enable the formal characterization and the effective computation of the sought supervisor. With these predicates available, a distributed representation for the sought supervisor that is appropriate for real-time implementation is eventually obtained through an adaptation of the relevant distributed algorithm that is provided by the current s-DES SC theory.
  •  
40.
  • Riazi, Sarmad, 1986, et al. (författare)
  • A Column Generation-Based Gossip Algorithm for Home Healthcare Routing and Scheduling Problems
  • 2019
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 16:1, s. 127-137
  • Tidskriftsartikel (refereegranskat)abstract
    • Home healthcare (HHC) is a service that dispatches caregivers to people in need of healthcare who live in the home. The task assignment and route generation for caregivers can be formulated as an extension of the well-known vehicle routing problem with time windows (VRPTW). Currently, the most successful exact algorithms for VRPTW are based on a framework combining column generation (CG) and branching. Although such methods could be successful for HHC routing and scheduling problem (HHCRSP) as well, fast approximate algorithms are appealing, especially for large problems. In an early version of this paper, we employed a heuristic distributed gossip algorithm to solve HHCRSP. In this paper, we integrate the gossip algorithm with a local solver based on CG, which makes it an effective algorithm for larger problem instances. As it will be shown with extensive numerical experiments, for large problem instances, gossip-CG performs better than the pure CG. Note to Practitioners-The task of routing and scheduling caregivers for HHC providers can be formulated as a mathematical problem that is theoretically challenging to solve to optimality for large-scale problems involving many clients and caregivers. Although extensive research and tools for tackling this problem already exist, in practice, even in developed countries, it is still common to rely on schedules generated manually by staff. What we present in this paper is the summary of our theoretical work on tackling such problems. The benefit of the framework that we propose, the CG-based gossip method, is that it can be preempted at any time if the staff requires to obtain a good schedule as soon as possible. If ample time is available, one can let our algorithm to run for a longer period of time to generate even shorter routes.
  •  
41.
  • Riazi, Sarmad, 1986, et al. (författare)
  • Energy and Peak Power Optimization of Time-Bounded Robot Trajectories
  • 2017
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 14:2, s. 646-657
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper, as an outcome of the EU project AREUS, heralds an optimization procedure that reduces up to 30% of energy consumption and up to 60% in peak power for the trajectories that have been tested on real industrial robots. We have evaluated a number of cost functions and tested our algorithm for a variety of scenarios such as varying cycle times, payloads, and single/multirobot cases in both ac- and dc-operated robot cells. The significance of our work is not only in the impressive savings, simplicity of implementation, and preserving path and cycle time, but also in the variety of test scenarios that include different kinds of KUKA robots. We have carried out the optimization and experiments in as realistic conditions as possible.
  •  
42.
  • Riazi, Sarmad, 1986, et al. (författare)
  • Energy Optimization of Large-Scale AGV Systems
  • 2021
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 18:2, s. 638-649
  • Tidskriftsartikel (refereegranskat)abstract
    • We propose an efficient optimization method, which addresses several performance criteria such as makespan, maximum lateness, and the sum of tardiness for an automated guided vehicle (AGV) system, together with its energy consumption. We show that the most important factors in energy consumption of AGVs are their cruise velocities and traveled distances. We also demonstrate that optimizing the productivity-related performance criteria also reduces energy consumption through less traveled distance. It also allows for the reduction of the cruise velocity that leads to more energy savings. Our experiments demonstrate that the optimization method outperforms the existing traffic controller with respect to the performance criteria and reduces energy consumption. The proposed method can reduce the energy consumption by around 38%, while the values of makespan, lateness, and tardiness remain better than those obtained from the existing traffic controller. An important advantage of this paper is that the evaluations are based on collected data from a real large-scale manufacturing plant.
  •  
43.
  • Riazi, Sarmad, 1986, et al. (författare)
  • Using CP/SMT Solvers for Scheduling and Routing of AGVs
  • 2021
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 18:1, s. 218-229
  • Tidskriftsartikel (refereegranskat)abstract
    • An improved method for solving conflict-free scheduling and routing of automated guided vehicles is proposed in this article, with promising results. This is achieved by reformulating the mathematical model of the problem, including several improvements and speedup strategies of an existing Benders decomposition method. A new heuristic is also presented that quickly yields high-quality solutions. Moreover, a real-large-scale industrial instance is solved using an open-source satisfiability module theories solver and a commercial constraint programming solver. According to the results, both of these general-purpose solvers can effectively solve the proposed models. Note to Practitioners - The problem of conflict-free routing and scheduling of automated guided vehicles (AGVs) in large-scale manufacturing systems has been an ever-present challenge for many AGV companies. Although these companies have developed rather efficient control policies and algorithms, retrofitting the existing heuristic to future's denser, more complicated, and more demanding AGV layouts is not guaranteed to be easy. Furthermore, the installed system will not necessarily be as efficient as expected. Currently, it is common to use heuristics to allocate vehicles to orders and route them. There are also rules of thumbs to avoid collisions and deadlocks. However, with increasing demand for high-performance AGV solutions, it is of interest to employ optimization algorithms that handle the order allocation, scheduling, and routing in a more efficient way. In this article, we present an improved method to tackle this issue, with promising results. We have developed our work in collaboration with a Swedish AGV company, and we have investigated a real-large-scale industrial instance as our case study.
  •  
44.
  • Roselli, Sabino Francesco, 1992, et al. (författare)
  • A Compositional Algorithm for the Conflict-Free Electric Vehicle Routing Problem
  • 2022
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 19:3, s. 1405-1421
  • Tidskriftsartikel (refereegranskat)abstract
    • The Conflict-Free Electric Vehicle Routing Problem (CF-EVRP) is an extension of the Vehicle Routing Problem (VRP), a combinatorial optimization problem of designing routes for vehicles to visit customers such that a cost function, typically the number of vehicles or the total travelled distance, is minimized. The problem finds many logistics applications, particularly for highly automated logistic systems for material handling. The CF-EVRP involves constraints such as time windows on the delivery to the customers, limited operating range of the vehicles, and limited capacity on the number of vehicles that a road segment can accommodate at the same time. In this paper, the compositional algorithm ComSat for solving the CF-EVRP is presented. The algorithm iterates through the sub-problems until a globally feasible solution is found. The proposed algorithm is implemented using an optimizing SMT-solver and is evaluated against an implementation of a previously presented monolithic model. The soundness and completeness of the algorithm are proven, and it is benchmarked on a set of generated problems and found to be able to solve problems of industrial size.
  •  
45.
  • Roselli, Sabino Francesco, 1992, et al. (författare)
  • On the Use of Equivalence Classes for Optimal and Suboptimal Bin Packing and Bin Covering
  • 2021
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 18:1, s. 369-381
  • Tidskriftsartikel (refereegranskat)abstract
    • Bin packing and bin covering are important optimization problems in many industrial fields, such as packaging, recycling, and food processing. The problem concerns a set of items, each with its own value, that are to be sorted into bins in such a way that the total value of each bin, as measured by the sum of its item values, is not above (for packing) or below (for covering) a given target value. The optimization problem concerns minimizing, for bin packing, or maximizing, for bin covering, the number of bins. This is a combinatorial NP-hard problem, for which true optimal solutions can only be calculated in specific cases, such as when restricted to a small number of items. To get around this problem, many suboptimal approaches exist. This article describes the formulations of the bin packing and covering problems that allow finding the true optimum, for instance, counting hundreds of items using general-purpose MILP-solvers. Also presented are suboptimal solutions that come within less than 10% of the optimum while taking significantly less time to calculate, even ten to 100 times faster, depending on the required accuracy. Note to Practitioners - A typical case for bin covering is in food processing where food items are automatically sorted into trays of similar weight so that the overweight is minimized. Another application is in recycling, where items such as batteries should be put in crates of similar weight, so that the crates do not exceed a target weight due to later manual handling, but, at the same time, we want as few crates as possible. This is a bin packing problem. On an industrial scale, these tasks are fully automated. Though modern software tool's efficiency to solve bin sorting problems has increased significantly in later years, the problems are inherently tough in the sense that the solution time grows exponentially with the number of items. This limits the problem sizes that can be solved to optimality within a reasonable time. Therefore, much research has focused on heuristic rules that give reasonable solving times while not giving the true optimal number of bins. However, in many cases, the true optimal solution is preferable, and sometimes even necessary, so this is an industrially interesting problem. This article describes an approach to solve the bin packing and covering problems to the true optimum that increases the limit of the number of items that can typically be handled. This is done by observing that items of the same value need not be distinguished. Instead, we can formulate packing/covering problems over item values rather than individual items and sort integer numbers of these values into bins, which allows us to solve to optimum for more than 500 items in a reasonable time. In addition, by redefining what we mean by the same value, we can consider more items to have the same value and achieve even better calculation efficiency.
  •  
46.
  • Spensieri, Domenico, 1978, et al. (författare)
  • An Iterative Approach for Collision Free Routing and Scheduling in Multirobot Stations
  • 2016
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 13:2, s. 950-962
  • Tidskriftsartikel (refereegranskat)abstract
    • This work is inspired by the problem of planning sequences of operations, as welding, in car manufacturing stations where multiple industrial robots cooperate. The goal is to minimize the station cycle time, i.e., the time it takes for the last robot to finish its cycle. This is done by dispatching the tasks among the robots, and by routing and scheduling the robots in a collision-free way, such that they perform all predefined tasks. We propose an iterative and decoupled approach in order to cope with the high complexity of the problem. First, collisions among robots are neglected, leading to a min–max Multiple Generalized Traveling Salesman Problem (MGTSP). Then, when the sets of robot loads have been obtained and fixed, we sequence and schedule their tasks, with the aim to avoid conflicts. The first problem (min–max MGTSP) is solved by an exact branch and bound (B&B) method, where different lower bounds are presented by combining the solutions of a min–max set partitioning problem and of a Generalized Traveling Salesman Problem (GTSP). The second problem is approached by assuming that robots move synchronously: a novel transformation of this synchronous problem into a GTSP is presented. Eventually, in order to provide complete robot solutions, we include path planning functionalities, allowing the robots to avoid collisions with the static environment and among themselves. These steps are iterated until a satisfying solution is obtained. Experimental results are shown for both problems and for their combination. We even show the results of the iterative method, applied to an industrial test case adapted from a stud welding station in a car manufacturing line.
  •  
47.
  • Sundström, Nina, 1980, et al. (författare)
  • Conflict Between Energy, Stability, and Robustness in Production Schedules
  • 2017
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 14:2, s. 658-668
  • Tidskriftsartikel (refereegranskat)abstract
    • A systematic method to evaluate the conflict between robustness, stability, and energy consumption is proposed in this paper. Energy optimization is combined with robust scheduling techniques to analyze the tradeoff. In rescheduling, slack is often used to protect a schedule from disruptions. However, results from the literature on energy minimization show that a reduction in energy consumption is achieved by extending the execution time of operations. Thus, slack in schedules is diminished on behalf of longer execution times. The proposed method, which quantitatively shows this conflict, is based on a multiobjective optimization formulation where efficient computation of the involved criteria is developed. This includes a convex surrogate stability measure that makes it possible to evaluate different operation sequences by a mixed-integer nonlinear programming formulation. Previous works connecting the two research fields use simulation for analyzing the impact of disruptions in order to generate robust production schedules. Our results show that an increase in energy efficiency comes at a cost of reducing stability and robustness and hence becoming more sensitive to disruptions.
  •  
48.
  • Vergnano, Alberto, et al. (författare)
  • Modeling and Optimization of Energy Consumption in Cooperative Multi-Robot Systems
  • 2012
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 9:2, s. 423-428
  • Tidskriftsartikel (refereegranskat)abstract
    • Reduction of energy consumption is important for reaching a sustainable future. This paper presents a novel method for optimizing the energy consumption of robotic manufacturing systems. The method embeds detailed evaluations of robots' energy consumptions into a scheduling model of the overall system. The energy consumption for each operation is modeled and parameterized as function of the operation execution time, and the energy-optimal schedule is derived by solving a mixed-integer nonlinear programming problem. The objective function for the optimization problem is then the total energy consumption for the overall system. A case study of a sample robotic manufacturing system and an experiment on an industrial robot are presented. They show that there exists a real possibility for a significant reduction of the energy consumption in comparison to state-of-the-art scheduling approaches. Note to Practitioners-The motivation for this work is the great interest of companies on energy consumption optimization, looking for cost reduction and sustainability in manufacturing. Existing optimization methods focus on different levels of details. A high-level model would be able to optimize the overall system. Unfortunately, due to the high computational cost, it can hardly consider the deep level of mechanical and electrical parameters, which determine the real energy consumption. This paper presents a novel method to embed detailed energy consumption models into a scheduling optimization problem. An effective parameterization of the time variables reduces the model complexity, allowing the optimizer to reschedule the complete sequence of operations for minimizing the total energy consumption, while keeping a fixed cycle time. The method has been integrated into a commercial tool for robot programming. The optimization is applicable both on new and existing robotic systems, since the required modifications are limited to the operations rescheduling, and no investments on new hardware are expected.
  •  
49.
  • Wang, Lihui, et al. (författare)
  • ASP : An Adaptive Setup Planning Approach for Dynamic Machine Assignments
  • 2010
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - : IEEE. - 1545-5955 .- 1558-3783. ; 7:1, s. 2-14
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper presents a decision-making approach towards adaptive setup planning that considers both the availability and capability of machines on a shop floor. It loosely integrates scheduling functions at the setup planning stage, and utilizes a two-step decision-making strategy for generating machine-neutral and machine-specific setup plans at each stage. The objective of the research is to enable adaptive setup planning for dynamic job shop machining operations. Particularly, this paper covers basic concepts and algorithms for one-time generic setup planning, and run-time final setup merging for dynamic machine assignments. The decision-making algorithms validation is further demonstrated through a case study.
  •  
50.
  • Wigström, Oskar, 1986, et al. (författare)
  • High-Level Scheduling of Energy Optimal Trajectories
  • 2013
  • Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 10:1, s. 57-64
  • Tidskriftsartikel (refereegranskat)abstract
    • The reduction of energy consumption is today addressed with great effort in manufacturing industry. In this paper, we improve upon a previously presented method for robotic system scheduling. By applying dynamic programming to existing trajectories, we generate new energy optimal trajectories that follow the same path but in a different execution time frame. With this new method, it is possible to solve the optimization problem for a range of execution times for the individual operations, based on one simulation only. The minimum energy trajectories can then be used to derive a globally energy optimal schedule. A case study of a cell comprised of four six-link manipulators is presented, in which energy optimal dynamic time scaling is compared to linear time scaling. The results show that a significant decrease in energy consumption can be achieved for any given cycle time.
  •  
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