| 1. |
- Bertilsson, Erik, et al.
(författare)
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Assessment of manikin motions in IMMA
- 2012
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Ingår i: Advances in applied human modeling and simulation. - Boca Raton : CRC Press. - 9781439870310 - 9781439870327 - 9780429061943 ; , s. 235-244
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Bokkapitel (refereegranskat)abstract
- When evaluating human-machine interaction in a virtual environment using Digital human modelling (DHM) it is important to ensure that the predicted motions lie within the range of behavioural diversity for different people within a population. This paper presents a study in which a comparison is made between motions predicted by the DHM tool IMMA (Intelligently Moving Manikin) and motions from real humans stored in a motion database. Results show similar motions but the predicted motions were in total statistically significantly different compared to the motions performed by real persons. The differences are most likely due to the balance function and joint constraints that the IMMA tool uses for predicting motions. Differences can also be due to other factors, aside of body size, such as age, gender or strength that affects the movement behaviour.
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| 2. |
- Keyvani, Ali, 1978-, et al.
(författare)
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A Virtual Manufacturing Approach for Integrating Fixture Design with Process Planning
- 2009
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Ingår i: Proceedings of the sixth CIRP-sponsored International Conference on Digital Enterprise Technology. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 9783642104299 ; 66, s. 483-496
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Computer Aided Process Planning has received more attention recently due to considerable progress in the aspects of both technology and theory. Beside the traditional trends and efforts to integrate the product design and process planning activities usually referred to as concurrent engineering, virtual manufacturing tools have opened new horizons to this domain. This paper describes how to combine an existing modular fixture design with process planning and simulation tools. The proposed concurrent architecture consists of a functional model and an operational workflow for the design of modular fixtures within the process-planning phase. Two different paradigms, the Variant and the Generative, are discussed in relation to the proposed architecture. Fixtures for Body in White lines are a crucial design problem in the automotive industry. Therefore, the proposed architecture has been tested and investigated in such an environment.
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| 3. |
- Keyvani, Ali, 1978, et al.
(författare)
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Considerations for aggregation of motion-captured files in structured databases for DHM applications
- 2013
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Ingår i: DHM 2013, Second International Digital Human Modeling Symposium.
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Konferensbidrag (refereegranskat)abstract
- One way of enhancing motion simulation in digital human modeling (DHM) tools is to use data-driven methods which are based on real motion data. In spite of the availability of motion captured datasets which are offered for different purposes by commercial and research institutes, aggregation and integration of these motions in a unified and structured database system is not straight forward. Lack of this integration, limits the availability of existing data and causes DHM tools not to be able to use the data efficiently. Also for the researchers, comparison and analysis of data get very hard if not impossible. When searching for a specific motion pattern, it is optimal if the stored data in the database can be directly compared, analyzed and then retrieved if necessary. This study highlights several sources of incompatibility among motion capture files which shall be considered when implementing a comprehensive data management system for manipulating motion captured data. Subsequently, these incompatibilities are analyzed in more detail and necessary considerations and possible solutions are proposed in order to overcome the integration obstacles.
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| 4. |
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| 5. |
- Keyvani, Ali, 1978-, et al.
(författare)
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Motion synthesizer platform for moving manikins
- 2012
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Ingår i: 2012 AHFE International Conference 21-25 July 2012 Hilton San Francisco, Union Square, California. - : AHFE. - 9780979643552 ; , s. 545-554
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Konferensbidrag (refereegranskat)
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| 6. |
- Keyvani, Ali, 1978, et al.
(författare)
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Motion synthesizer platform for moving manikins
- 2012
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Ingår i: Advances in Applied Human Modeling and Simulation. - : CRC Press. - 9781439870327 - 9780979643552 ; , s. 545-554
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Digital Human Models are getting more applicable in simulation of the human postures/actions during different product development stages. Despite the existence of various modeling techniques, simulated motions are still looking unrealistic. It was identified that one promising way of generating more realistic motions is to use real human motion data as a source. A synthesizer platform is presented in this study which is able to store motions taken from real human in a database and synthesize new motions using already existing motions. The platform is also able to search the database, analyze the data, and feed the data to DHM tools. The platform functionality was tested within two areas: a) by composing new motions by combining the arm motions and walking motions from different subjects and b) by using analysis tools to compare generated motion in a commercial software against captured motions from real human. The obtained results show promising applications of the platform as it can be used to generate new motions and/or analyzing the motions.
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| 7. |
- Keyvani, Ali, 1978-, et al.
(författare)
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Schema for Motion Capture Data Management
- 2011
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Ingår i: Lecture Notes in Computer Science. 3rd International Conference on Digital Human Modeling, ICDHM 2011. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. - 9783642217982 ; , s. 99-108
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Konferensbidrag (refereegranskat)abstract
- A unified database platform capable of storing both motion captured data and information about these motions (metadata) is described. The platform stores large motion captured data in order to be used by different applications for searching, comparing, analyzing and updating existing motions. The platform is intended to be used to choose a realistic motion in simulation of production lines. It is capable of supporting and handling different motion formats, various skeleton types and distinctive body regions in a uniform data model. Extended annotating system is also introduced to mark the captured data not only in the time domain (temporal) but also on different body regions (spatial). To utilize the platform, sample tests are performed to prove the functionality. Several motion captured data is uploaded to the database while MATLAB is used to access the data, ergonomically analyze the motions based on OWAS standard, and add the results to the database by automatic tagging of the postures.
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| 8. |
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| 9. |
- Keyvani, Ali, 1978-
(författare)
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Structuring and use of motion data for computer manikin work task simulations
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Modelling and simulation of human motions are of great interest for a number of industrial applications such as ergonomics and production planning. Over time, efforts have been made to provide computerized human models with biomechanically accurate underlying skeleton and realistically rendered volumetric representation of muscles, skin, clothes, etc. known as computer manikins. Despite considerable progress in computational methods for human motion generation in these models, there are still major challenges to generate natural looking motions for daily routine tasks for example in manual assembly lines. This research work proposes a software platform, related methods, and data structures to support use of real motion data for simulating and analysing routine work tasks. One contribution of this thesis is to find ways to deploy motion data in a uniform and efficient manner. The outcomes are a data schema, standards for data conversions, and procedures to aggregate motion data in a unified database. Another part of this thesis is dedicated to 'generating new motions by re-using stored data'. This is done by a synthesizer platform consisting of modules which are able to decompose tasks into primary motions, to search and retrieve motion pieces from the motion database, and to compose a new motion based on the required specifications. In addition, this thesis, presents a method to analyse the generated motions using time-varied motion data. Results of this work contribute in extending current tool functionalities by simulating complicate routine motions which, if not impossible, are very hard to simulate using today's computational algorithms. This work also improves the use of time-varied direct measurement analysis tools against traditional static observational methods.
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| 10. |
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| 11. |
- Keyvani, Ali, 1978
(författare)
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Toward motion-capture-based digital human modelling
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Digital Human Models (DHMs) are getting more applicable in the simulation of human postures/actions inside virtual production systems. Despite the existence of various modeling techniques, simulated motions are still looking unrealistic. One way to increase the natural looking of simulated motions is to use real human data as a source for motion simulation algorithms. Motion capture is a common tool to record real human motions and has been widely used in animation and game applications. It is observed that although many research studies embrace the profitability of using real human data for motion simulation in DHM tools, the existing motion capture data can be hardly reused in a systematic way. Number of reasons such as variations in skeleton configurations and motion formats, and non-efficient annotating of motions are identified as the reasons for this problem.In this thesis first a data schema for motion capture data management is presented. The purpose of such schema is to store and manipulate motion data in a way that mentioned problems are not arising. A synthesizer platform is also presented which is able to store motions taken from real human in the database and synthesize new motions using already existing motions. The platform is able to search the database, analyze the data, and feed the data to DHM tools. The platform functionality was tested within two areas: a) by composing new motions by combining the arm motions and walking motions from different subjects and b) by using analysis tools to compare generated motions in a commercial software against captured motions from real human.
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| 12. |
- Keyvani, Ali, 1978-, et al.
(författare)
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Using methods-time measurement to connect digital humans and motion databases
- 2013
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Ingår i: Lecture Notes in Computer Science. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0302-9743 .- 1611-3349. - 9783642391811 ; 8026:Part 2, s. 343-352
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Tidskriftsartikel (refereegranskat)abstract
- To simulate human motions in DHM tools, using techniques which are based on real human data is one promising solution. We have presented a solution in this study to connect motion databases with DHM tools. We have showed that using a motion database with MTM-based annotations is a promising way in order to synthesize natural looking motions. A platform consists of a Motion Database, a Motion Generator, and a DHM tool was introduced and tested. The results showed successful application of the presented platform in the designed test case. © 2013 Springer-Verlag.
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| 13. |
- 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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| 14. |
- Rhen, Ida-Märta, 1975, et al.
(författare)
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Ergonomic risk assessment in DHM tools employing motion data : Exposure calculation and comparison to epidemiological reference data
- 2018
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Ingår i: International Journal of Human Factors Modelling and Simulation. - Olney : InderScience Publishers. - 1742-5549 .- 1742-5557. ; 6:1, s. 31-64
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Tidskriftsartikel (refereegranskat)abstract
- Digital human modelling (DHM) allows ergonomic risk assessment to be performed at early stages of design and development. Such assessment is typically based on observational methods, which do not take advantage of the potential of DHM tools to provide precise posture and motion data. This paper describes and illustrates an alternative assessment approach employing DHM tools, inspired by risk assessment based on direct measurements. A literature survey established a reference database of epidemiological associations between exposure and wrist-related disorders. This approach is illustrated by a DHM simulation of a car assembly task. Wrist posture and motion were simulated and compared to the database, predicting the prevalence of work-related musculoskeletal disorders on the basis of direct measurements.
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