| 1. |
- Hanson, Lars, et al.
(författare)
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Industrial path solutions - intelligently moving manikins
- 2019
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Ingår i: DHM and Posturography. - London : Academic Press. - 9780128167137 ; , s. 115-124
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- IPS IMMA (Industrial Path Solutions - Intelligently Moving Manikins) is a digital human modeling tool developed in close cooperation between academia and industry in Sweden. The academic consortium behind the software consists of expertise within applied mathematics, ergonomics, and engineering. The development of IMMA was initiated from the vehicle industries’ need of an effective, efficient, objective, and user-friendly software for verification of manufacturing ergonomics. The ‘Industrial path solutions - intelligently moving manikins’ chapter consists of two main sections: the first about the commercially available tool, and the second about current or recent research projects developing the software further. Commercial IPS IMMA is presented by describing the biomechanical model and appearance, anthropometrics module, motion prediction, instruction language, and ergonomics evaluation. The research projects focus on dynamic motions simulation, muscle modelling and application areas such as human-robot collaboration, occupant packaging, and layout planning.
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| 2. |
- Spensieri, Domenico, 1978, et al.
(författare)
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An Iterative Approach for Collision Free Routing and Scheduling in Multirobot Stations
- 2016
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Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 13:2, s. 950-962
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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.
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| 3. |
- Spensieri, Domenico, 1978, et al.
(författare)
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Optimal Robot Placement for Tasks Execution
- 2016
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Ingår i: Procedia CIRP - 6th CIRP Conference on Assembly Technologies and Systems, CATS 2016, Gothenburg, Sweden, 16-18 May 2016. - : Elsevier BV. - 2212-8271. ; 44, s. 395-400
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Konferensbidrag (refereegranskat)abstract
- Automotive assembly cells are cluttered environments, including robots, workpieces, and fixtures. Due to high volumes and several product variants assembled in the same cell, robot placement is crucial to increase flexibility and throughput. In this paper, we propose a novel method to optimize the base position of an industrial robot with the objective to reach all predefined tasks and minimize cycle time: robot inverse kinematics and collision avoidance are integrated together with a derivative-free optimization algorithm. This approach is successfully used to find feasible solutions on industrial test cases, showing up to 20% cycle time improvement.
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| 4. |
- Spensieri, Domenico, 1978
(författare)
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Planning Robotic Assembly Sequences
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the automotive industry, short ramp up times and high product quality drive the development toward state-of-the-art solutions both in the research and industrial perspective. In addition to that, a sustainable industry requires optimized equipment utilization, in terms of materials used and consumed energy. This thesis is a contribution in the never-ending process of achieving the goals above described and has as focus virtual product realization for robot assembly. Virtual methods, indeed, decrease the need for prototyping and can simulate, and thereafter optimize the robotic assembly process. In order to optimize equipment utilization and assembly time for a new product, this thesis presents algorithms and tools to check geometrical feasibility and minimize cycle time in multirobot stations. Robustness for the assembly process is very important, therefore geometrical variation is also considered during path and assembly planning. In fact, one of the contribution is a tool integrating robot path planning and geometrical variation for robot assembly. The main idea is to let the robot move in the workspace areas where there is less uncertainty. Another tool presented integrates assembly design, sequence optimization and path planning, which can be used in order to evaluate different concepts regarding locating scheme and the robustness in its critical dimensions. The major contribution is a new approach to schedule robot operations to avoid collisions and minimize cycle time for multirobot stations. Two articles present algorithms and tools to distribute the operations workload among several robots and coordinate them. These new ideas and their implementation in software platforms can improve virtual product realization for robotic applications by requiring less expert knowledge from the user and making automatic optimization not only part of delivering a detailed solution but also letting it be part of the decision making process.
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| 5. |
- Åblad, Edvin, 1991, et al.
(författare)
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Intersection-Free Geometrical Partitioning of Multirobot Stations for Cycle Time Optimization
- 2018
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Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955.
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Tidskriftsartikel (refereegranskat)abstract
- Assembly cells, where multiple robots perform sets of tasks, often face the challenge to minimize cycle time and avoid collisions. Collisions are avoided by introducing synchronization schemes among the robots, preventing shared volumes of the workspaces to be simultaneously entered. Synchronization often increases the cycle time and makes the robot programming more difficult to generate, adjust, and maintain. In this paper, we present a novel method to maximize throughput while eliminating all synchronizations among robots. We devise algorithms to minimize cycle time generating no intersection among robots at any time during their paths. First, a surrogate model for minimizing cycle time is provided and solved to optimality: each task is assigned to a robot in a way that no collision occurs. Afterward, the entire workspace is partitioned such that each robot's workspace is separated from the others. Finally, robot paths are generated automatically in order to avoid collisions with the environment and remaining in their precomputed partitions. In the rare cases where some of these steps fail, a feedback procedure redistributing the tasks or modifying the partitions is adopted. Furthermore, since the surrogate model approximates cycle time, several solutions are generated and evaluated based on better approximations of the model. The results are convincing: computational experience on different cases from the automotive industry shows that it is possible to generate programs where the robots never intersect with each other and achieve cycle times comparable to the ones generated allowing synchronization.
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