| 1. |
- Bergagård, Patrik, 1984, et al.
(författare)
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On restart of automated manufacturing systems using restart states
- 2015
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Ingår i: IEEE International Conference on Automation Science and Engineering. - 2161-8070 .- 2161-8089. - 9781467381833 ; 2015-October, s. 166-167
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Konferensbidrag (refereegranskat)abstract
- Highly automated manufacturing systems have gained industrial popularity for their ability to combine high product volumes with high product quality. The high cost of investment in combination with many linked manufacturing systems in a factory, requires that the production runs smoothly with high utilization of the resources and that stoppages are avoided. One major reason for stoppages is the occurrence of errors. A wide variety of possible faults, such as badly fixated parts, broken actuators, and teething problems in the system, may cause errors that lead to an unsynchronization between the control system and the physical system that consequently lead to production stoppages [1,2]. The succeeding error recovery is often a complex and thereby time consuming process that typically requires operator involvement [3]. To plan for restart after errors already during the development of the system would therefore greatly support the online restart process and reduce the time the production is undesirably stopped. The common industrial practice to deal with such non-intended progress is to extend the control system with tailor-made solutions to account for foreseen errors [4,5]. This extension is both time consuming and there is no guarantee that all relevant errors are handled.
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| 2. |
- Björkenstam, Staffan C, 1981, et al.
(författare)
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Exploiting sparsity in the discrete mechanics and optimal control method with application to human motion planning
- 2015
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Ingår i: IEEE International Conference on Automation Science and Engineering. - 2161-8070 .- 2161-8089. - 9781467381833 ; , s. 769-774
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Konferensbidrag (refereegranskat)abstract
- The discrete equations of motion derived using a variational principle are particularly attractive to be used in numerical optimal control methods. This is mainly because: i) they exhibit excellent energy behavior, ii) they extend gracefully to systems with holonomic constraints and iii) they admit compact representation of the discrete state space. In this paper we propose the use of sparse finite differencing techniques for the Discrete Mechanics and Optimal Control method. In particular we show how to efficiently construct estimates of the Jacobian and Hessian matrices when the dynamics of the optimal control problem is discretized using a variational integrator. To demonstrate the effectiveness of this scheme we solve a human motion planning problem of an industrial assembly task, modeled as a multibody system consisting of more than one hundred degrees of freedom.
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| 3. |
- Fei, Zhennan, 1984, et al.
(författare)
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Symbolic computation of boundary unsafe states in complex resource allocation systems using partitioning techniques
- 2015
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Ingår i: IEEE International Conference on Automation Science and Engineering. - 2161-8070 .- 2161-8089. - 9781467381833 ; , s. 799-806
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Konferensbidrag (refereegranskat)abstract
- In some recent work, we proposed a binary decision diagram (BDD-) based approach for the development of the maximally permissive deadlock avoidance policy (DAP) for complex resource allocation systems (RAS), that is based on the identification and the explicit storage of a set of critical states in the underlying RAS state-space. The work presented in this paper seeks to extend the applicability of the aforementioned results by coupling them with a partitioning technique for the more efficient storage and processing of the BDD that encodes the underlying state space. The reported numerical experimentation demonstrates the increased efficiency of the new algorithm w.r.t. its space and time complexity, compared to the previous method that uses a more monolithic representation of the RAS state-space. The last part of the paper also discusses some further potential advantages of the presented method, including its amenability to a parallelized implementation and its ability to cope effectively and efficiently with uncontrollable behavior.
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| 4. |
- Gleeson, Daniel, 1988, et al.
(författare)
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Optimizing robot trajectories for automatic robot code generation
- 2015
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Ingår i: IEEE International Conference on Automation Science and Engineering. - 2161-8070 .- 2161-8089. - 9781467381833 ; , s. 495-500
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Konferensbidrag (refereegranskat)abstract
- In manufacturing industry, the automation of robot trajectory planning and robot code generation lowers the development and assessment times of new products and models, increasing the flexibility of a robotic production line. This is of increasing importance in a number of industries where new products and new models are constantly being developed. This paper presents a method that automatically generates robot code for collision free trajectories. Starting with a collision free piecewise linear joint space trajectory, a direct transcription optimal control method is used, iteratively, to improve the trajectory while maintaining a desired clearance. The final solution is a collision free robot trajectory defined by a set of parameters, e.g. joint space via points and TCP-zone radii, that can be used to automatically generate functional RAPID code for an industrial robot. The algorithm is designed to be easily extendable. For example, by changing the constraints on the trajectory or by including energy consumption as an objective. A successful test of the algorithm has been carried out on an industrial stud welding station using the ABB virtual controller, indicating a 10% improvement in motion time.
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| 5. |
- Lennartson, Bengt, 1956, et al.
(författare)
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Optimization of hybrid Petri nets with shared variables
- 2015
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Ingår i: IEEE International Conference on Automation Science and Engineering. - 2161-8070 .- 2161-8089. - 9781467381833 ; , s. 1395-1396
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Konferensbidrag (refereegranskat)abstract
- A generalized modeling framework for hybrid systems, including both discrete event and continuous-time dynamics, is presented in this paper. It is based on a new type of hybrid Petri nets, involving both modular structures, discrete shared variables and flexible transition predicates. The continuous-time dynamics is given by local differential equations, in a style similar to hybrid automata. This can be compared with existing hybrid Petri nets, where also the continuous-time dynamics is represented graphically, but then in reality limiting the continuous-time behavior to simple flow processes. The hybrid Petri net proposed in this paper works well for any type of continuous-time dynamics, including even differential inclusions, and the result is a compact, flexible and readable mix of graphical and equation based representations. The proposed modeling framework is also applied to a physical robot cell, where the energy consumption of the robot motions is minimized based on a hybrid Petri net model, easily transformed to a mixed integer nonlinear programming problem. The resulting optimization procedure is shown to reduce the energy consumption of the real robot cell by approximately 50%.
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| 6. |
- Lennartson, Bengt, 1956, et al.
(författare)
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Welcome message from general and program chairs
- 2015
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Ingår i: IEEE International Conference on Automation Science and Engineering. - 2161-8070 .- 2161-8089. - 9781467381833 ; 2015-October
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Pellicciari, M., et al.
(författare)
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AREUS — Innovative hardware and software for sustainable industrial robotics
- 2015
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Ingår i: IEEE International Conference on Automation Science and Engineering. - 2161-8070 .- 2161-8089. - 9781467381833 ; , s. 1325-1332
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Konferensbidrag (refereegranskat)abstract
- Industrial Robotics (IR) may be envisaged as the key technology to keep the manufacturing industry at the leading edge. Unfortunately, at the current state-of-the-art, IR is intrinsically energy intensive, thus compromising factories sustainability in terms of ecological footprint and economic costs. Within this scenario, this paper presents a new framework called AREUS, focusing on eco-design, eco-programming and Life Cycle Assessment (LCA) of robotized factories. The objective is to overcome current IR energetic limitations by providing a set of integrated technologies and engineering platforms. In particular, novel energy-saving hardware is firstly introduced, which aim at exchanging/storing/recovering energy at factory level. In parallel, innovative engineering methods and software tools for energy-focused simulation are developed, as well as energy-optimal scheduling of multi-robot stations. At last, LCA methods are briefly described, which are capable to assess both environmental and economic costs, linked to the flows of Material, Energy and Waste (MEW). A selected list of industrially-driven demonstration case studies is finally presented, along with future directions of improvement.
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| 8. |
- Riazi, Sarmad, 1986, et al.
(författare)
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Energy Optimization of Multi-robot Systems
- 2015
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Ingår i: IEEE International Conference on Automation Science and Engineering. - 2161-8070 .- 2161-8089. - 9781467381833 ; , s. 1345-1350
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Konferensbidrag (refereegranskat)abstract
- This paper presents an optimization algorithm that has been able to save up to 45% of the energy consumption of an industrial multi-robot system. The tool Sequence Planner now includes these algorithms, focusing on minimizing energy consumption. The goal has been to reduce the energy consumption of individual robots and robots interacting in a work station, without changing the original paths or the total cycle time. The presented algorithms are based on an efficient and rapid nonlinear model for optimizing the sequences of operations and the motion trajectories. Smart simplification of the optimization problem together with innovative tools for logging data and executing the optimized trajectories on real robots has resulted in 18% to 45% saving of the energy consumption in the presented test scenarios.
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| 9. |
- Semeniuta, O., et al.
(författare)
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Discrete event dataflow as a formal approach to specification of industrial vision systems
- 2015
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Ingår i: IEEE International Conference on Automation Science and Engineering. - 2161-8070 .- 2161-8089. - 9781467381833 ; , s. 849-854
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Konferensbidrag (refereegranskat)abstract
- The need for more flexible manufacturing systems stimulates the adoption of industrial robots in combination with intelligent computing resources and sophisticated sensing technologies. In this context, industrial vision systems play a role of inherently flexible sensing means that can be used for a variety of tasks within automated inspection, process control and robot guidance. When vision sensing is used within a large complex system, it is of particular importance to handle the complexity by introducing the appropriate formal methods. This paper overviews the challenges arising during design, implementation and application of industrial vision systems, and proposes an approach, dubbed Discrete Event Dataflow (DEDF), allowing to formally specify vision dataflow in the context of larger systems.
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| 10. |
- Sikström, Fredrik, 1971-, et al.
(författare)
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Model based feedback control of gas tungsten arc welding : An experimental study
- 2015
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Ingår i: Automation Science and Engineering (CASE), 2015 IEEE International Conference on. - : IEEE conference proceedings. - 2161-8070 .- 2161-8089. - 9781467381833 ; , s. 411-416
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Konferensbidrag (refereegranskat)abstract
- In order to obtain high structural integrity and joint performance in welding a transient heat conduction model has been utilized to design a model based feedback controller.Gas tungsten arc welding of work-pieces of austenitic steel have been simulated by the finite element method. The basis for controller design is a low order model obtained from parametric system identification. The identification has been performed both on the finite element simulation and on physical welding. The low order model responses show a good agreement with both the finite element simulation result and the physical process response. An experimental study has been performed to verify the approach. This study also explores what experiments are needed for a successful design. It is shown that model based control successfully mitigates perturbations that occur during welding.
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