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- Björkenstam, Staffan C, 1981, et al.
(author)
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Digital Human Motion Planning of Operation Sequences Using Optimal Control of Hybrid Systems
- 2020
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In: Advances in Transdisciplinary Engineering. ; 11, s. 115-120
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Conference paper (peer-reviewed)abstract
- In IPS-IMMA the operation sequence planning tool offers an easy and powerful way to construct, analyze, and simulate sequences of human operations. So far, the simulations created using this tool have been quasi-static solutions to the operation sequence. In this paper we present new functionality for motion planning of digital human operation sequences which also takes the dynamics of the human into consideration. The new functionality is based discrete mechanics and optimal control and will be seamlessly integrated into to the IPS-IMMA software through the operation sequence planning tool. First, the user constructs an operation sequence using the operation sequence planning tool in IPS-IMMA. The operation sequence is then converted into a discrete optimal control problem which is solved using a nonlinear programming solver. Finally, the solution can be played back and analyzed in the graphical interface of IPS-IMMA. In order to obtain physically correct solutions to complex sequences consisting of several consecutive and dependent operations, we view the digital human as a hybrid system, i.e. a system containing both continuous and discrete dynamic behavior. In particular, the optimal control problem is divided into multiple continuous phases, connected by discrete events. The variational integrators used in discrete mechanics are particularly well suited for modelling the dynamics of constrained mechanical systems, which is almost always the case when considering complex human models interacting with the environment. To demonstrate the workflow, we model and solve an industrial case where the dynamics of the system plays an important part in the solution.
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- Delfs, Niclas, et al.
(author)
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Automatic Creation of Manikin Motions Affected by Cable Forces
- 2014
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In: Procedia CIRP:CIRP Conference on Assembly Technologies and Systems, CATS 2014; Dresden; Germany; 12 May 2014 through 14 May 2014. - : Elsevier BV. - 2212-8271. ; 23, s. 35-40
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Conference paper (peer-reviewed)abstract
- Effective simulation of manual assembly operations considering ergonomic load and clearance demands requires detailed modeling of human body kinematics and motions, including balance and response to external forces.In this paper we address the interaction of humans with flexible objects. By incorporating detailed physics simulation of flexible objects into the creation of ergonomically feasible human motions, we are able to ergonomically assess manual assembly operations involving cables and hoses.The method is implemented and demonstrated on a challenging operation taken from the automotive industry; a wiring harness assembly.
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- Mårdberg, Peter, 1980, et al.
(author)
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A novel tool for optimization and verification of layout and human logistics in digital factories
- 2018
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In: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 72, s. 545-550
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Conference paper (peer-reviewed)abstract
- We introduce a novel digital factory layout tool that optimizes both the layout of machines and the corresponding ergonomic logistics considering space constraints. A model is constructed by tangible properties on machines and environment, regions on the floor and by ranking their mutual relations. An optimized layout is then computed based on the model, the relations and an ergonomic score for the human work tasks, which are automatically computed by digital manikins. The result is an optimized layout, visualized in 3D, with improved logistic routes. The layout tool has been implemented and successfully tested on a relevant industrial case.
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- Mårdberg, Peter, 1980, et al.
(author)
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Towards Enhanced Functionality and Usability of Giving Manikin Task Instructions in a DHM Tool
- 2023
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In: Advances in Digital Human Modeling. - Cham : Springer. - 9783031378508 - 9783031378485 ; 744, s. 44-51
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Conference paper (peer-reviewed)abstract
- There are many approaches on how to make digital manikins replicate how real humans perform tasks. The manikin motions can, for instance, be computed by algorithms based on task instructions from the DHM tool user. In this study, we investigate possibilities for improving the task instruction language used in the DHM software tools. The study focuses on identifying opportunities and challenges for how the task instruction language can be improved, and the goal of the study is to establish research questions and to create a research roadmap. The aims of the research questions and associated research and development are: (i) to make it easier to give task instructions; (ii) to reduce the variance in simulations results between different DHM tool users; and (iii) to improve the trustworthiness of the simulation results, related to issues such as manikin behavior and estimated motion times. The potential approaches that have been identified, and will be elaborated and discussed in this paper, with the DHM software tool IPS IMMA as base, are: (i) to enable the DHM tool user to give task instructions on a higher abstraction level than today; (ii) to incorporate functionality to automatically represent likely human behavior; and (iii) to improve the accuracy of time estimation of task performance.
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| 8. |
- Mårdberg, Peter, 1980, et al.
(author)
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Using a Formal High-level Language to Instruct Manikins to Assemble Cables
- 2014
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In: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 23:C, s. 29-34
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Conference paper (peer-reviewed)abstract
- In this paper, a formal high-level language is used to generate simulations where a manikin assembles flexible cables. The language generates assembly instructions for the manikin, which automatically performs the corresponding assembly motion with as good ergonomic as possible. Due to weight, stiffness and narrow regions, it may be difficult to perform an assembly of the cable. Our approach allows us to verify that it may be performed in an ergonomically sound way. The generated instructions are formally verified to ensure that assembly order is held and to prevent erroneous assembly states. The simulations have been made on industrial test cases.
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