| 1. |
- Björkenstam, Staffan C, 1981, et al.
(författare)
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Digital Human Motion Planning of Operation Sequences Using Optimal Control of Hybrid Systems
- 2020
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Ingår i: Advances in Transdisciplinary Engineering. ; 11, s. 115-120
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Konferensbidrag (refereegranskat)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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| 2. |
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| 3. |
- Delfs, Niclas, et al.
(författare)
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Automatic Creation of Manikin Motions Affected by Cable Forces
- 2014
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Ingår i: 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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Konferensbidrag (refereegranskat)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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| 4. |
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| 5. |
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| 6. |
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| 7. |
- 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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| 8. |
- Högberg, Dan, 1965-, et al.
(författare)
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DHM Based Test Procedure Concept for Proactive Ergonomics Assessments in the Vehicle Interior Design Process
- 2018
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Ingår i: Proceedings of the 20th Congress of the International Ergonomics Association (IEA 2018). - Cham, Switzerland : Springer. - 9783319960760 - 9783319960777 ; , s. 314-323
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Konferensbidrag (refereegranskat)abstract
- The development of a digital human modelling (DHM) based test procedure concept for the assessment of physical ergonomics conditions in virtual phases of the vehicle interior design process is illustrated and discussed. The objective of the test procedure is to be a valuable tool for ergonomic evaluations and decision support along the design process, so that ergonomic issues can be dealt with in an efficient, objective and proactive manner. The test procedure is devised to support companies in having stable and objective processes, in accordance with lean product development (LPD) philosophies. The overall structure and fundamental functionality of the test procedure concept is explained by a simplified use case, utilizing the DHM tool IPS IMMA to: define manikin families and manikin tasks; predict manikin motions; and visualize simulations and ergonomics evaluation outcomes.
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| 9. |
- Mårdberg, Peter, 1980, et al.
(författare)
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A novel tool for optimization and verification of layout and human logistics in digital factories
- 2018
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 72, s. 545-550
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Konferensbidrag (refereegranskat)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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| 10. |
- Mårdberg, Peter, et al.
(författare)
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Introducing a Formal High-Level Language for Instructing Automated Manikins
- 2013
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Ingår i: 2nd International Digital Human Modeling.
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Konferensbidrag (refereegranskat)abstract
- Digital Human Modeling programs are important tools in virtual manufacturing that allow simulation of manual assembly work, long before any physical product has been built. By investigating the logistics, ergonomics and the interaction among the workers at an early stage, it may be possible to reduce the cost of design changes, increase the quality and to decrease the ramp-up time of a manufacturing process. However, far from all assembly operations are simulated, even if all the necessary data is available. One reason is the tedious work required to setup and to define all the motions needed by a manikin to perform a simulation. In each simulation, the manikin must be adjusted into the desired posture and the user must ensure that balance is held and that it avoids collision with objects in the environment. Thus, even a small case may be time consuming to simulate. This shows that there is a need of an easier way of instructing the manikins. In this work we propose a new formal high-level language for controlling an automated manikin. The language instructions are structured by a grammar, which defines a hierarchical tree for the manikin instructions. The low-level instructions contains basic functionality for maneuvering the manikin, such as Move, Position and Grasp, and higher levels contain more abstract instructions such as Get and Assemble. Thus, the high-level instructions define sequences of other instructions, whereas a low-level instruction corresponds to a direct instruction of the manikin. The set of available instructions that the manikin may perform during a simulation depends on the current state of the manikin and the objects at the assembly station. Thus, properties of objects, such as grasping and mating points, also help define the set of available instructions for the manikin. The order in which the different parts in the assembly operations have to be connected may also be considered when constructing instruction sequences for the manikin. Furthermore, the instruction sequences may be formally verified to ensure that the manikin only performs valid instructions. The language have been implemented in the manikin simulation software IMMA and tested on elementary cases with relevance to industrial applications. The results show that fewer steps are needed to perform a realistic simulation when the language is used compared to manually instructing the manikin. Furthermore, it is also shown that the instructions generated by the language are formally correct.
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| 11. |
- Mårdberg, Peter, 1980, et al.
(författare)
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Towards Enhanced Functionality and Usability of Giving Manikin Task Instructions in a DHM Tool
- 2023
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Ingår i: Advances in Digital Human Modeling. - Cham : Springer. - 9783031378508 - 9783031378485 ; 744, s. 44-51
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Konferensbidrag (refereegranskat)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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| 12. |
- Mårdberg, Peter, et al.
(författare)
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Using a formal high-level language and an automated manikin to automatically generate assembly instructions
- 2014
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Ingår i: International Journal of Human Factors Modelling and Simulation. - : InderScience Publishers. - 1742-5549. ; 4:3, s. 233-249
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an approach to automatically generate predetermined motion time system (PMTS) based assembly instruction lists from simulations within digital human modelling (DHM) software. A formal high-level instruction language is used to instruct an automated manikin to perform assembly operations. The manikin, the language and the assembled objects are composed into a discrete model. In a post-computational step, the model is used to construct PMTS instruction lists by mapping the manikin motions, assembled objects and the language instructions onto a set of PMTS keywords. The described approach is implemented in the DHM software IMMA and tested on industrial cases of manual assembly in the automotive industry.
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| 13. |
- Mårdberg, Peter, 1980, et al.
(författare)
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Using a Formal High-level Language to Instruct Manikins to Assemble Cables
- 2014
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 23:C, s. 29-34
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Konferensbidrag (refereegranskat)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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| 14. |
- Mårdberg, Peter, et al.
(författare)
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Using ergonomic criteria to adaptively define test manikins for design problems
- 2012
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Ingår i: Advances in applied human modeling and simulation. - Boca Raton : CRC Press. - 9781439870310 - 9781439870327 ; , s. 265-274
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Bokkapitel (refereegranskat)abstract
- Digital manikins give a powerful aid in evaluating assembly station ergonomics. A proper verification of an assembly station can avoid costly changes that might occur later on due to injuries and discomfort among the workers.However, how to select relevant test manikins for an evaluation is a non-trivial task, since the work of identifying which anthropometric variables that are critical is a tedious and time consuming process.Usually only a few variables are selected as a base for building the test manikins. Even if there exist Digital Human Modeling (DHM) software which allow the user to evaluate batches of manikins, the designer still have to select the anthropometric variables of those batches. When several dimensions are considered, the designer have to either use a set of predefined manikins, or determine which anthropometric variables to test and generate manikins based on the confidence intervals of these variables.When considering more complex assembly tasks, is it then true that these predetermined test manikins cover all the cases, or does there exist manikins that suffer from bad ergonomics even though all the test manikins turned out well?In this paper, we propose a new algorithm for automatically building a set of test manikins. The set is iteratively constructed from the ergonomics results obtained by simulating the assembly operation. Different manikins perform the assembly operation and the ergonomics is evaluated. The anthropometric variables which affect the ergonomics are identified and used to iteratively build up the next manikin. In this way the test manikins are always selected throughout the whole set instead of only considering the boundary manikins, or assuming that the same set of predetermined manikins represents the entire set in every assembly operation.The algorithm has been compared with a boundary method, and the results shows that the algorithm can find manikins with worse ergonomics than those tested by the boundary method.
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| 15. |
- Reinhard, René, et al.
(författare)
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The Use and Usage of Virtual Reality Technologies in Planning and Implementing New Workstations
- 2020
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Ingår i: DHM2020. - Amsterdam : IOS Press. - 9781643681047 - 9781643681054 ; , s. 388-397
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Konferensbidrag (refereegranskat)abstract
- Virtual reality (VR) technologies can support the planning and implementation of new workstations in various industry sectors, including in automotive assembly. Starting in the early planning stages, VR can help in identifying potential problems of new design ideas, e.g. through ergonomics analyses. Designers can then quickly change the virtual representations of new workstations to test solutions for the emerging difficulties. For this purpose, the actions and motions of prospective workers can be captured while they perform the work tasks in VR. The information can also be used as input for digital human modelling (DHM) tools, to instruct biomechanical human models. The DHM tools can then construct families of manikins that differ on anthropometric characteristics, like height, to simulate work processes. This paper addresses both existing technologies for gathering data on human actions and motions during VR usage and ways in which these data can be used to assist in designing new workstations. Here, a novel approach to translate a VR user’s actions into instructions for DHM tools through an event-based instruction sampling method is presented. Further, the challenges for utilizing VR are discussed through an industrial use case of the manual assembly of flexible cables in an automotive context.
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