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Viewing 1 to 30 of 69
2005-06-14
Technical Paper
2005-01-2688
S. Rahmatalla, H. J. Kim, M. Shanahan, C. C. Swan
The effect of restrictive clothing on functional reach and on balance and gait during obstacle crossing of five normal subjects is presented in this work using motion capture and stability analyses. The study has shown that restrictive clothing has considerably reduced participants' functional reach. It also forced the participants to change their motion strategy when they cross-higher obstacles. When crossing higher obstacles, the participants averted their stance foot, abducted their arms, flexed their torso, used longer stance time, and increased their hip angle in the medial-lateral (Rolling) and vertical (Yawing) directions. The stability analysis of a virtual human skeletal model with 18 links and 25 degrees of freedom has shown that participants' stability has become critical when they wear restrictive clothing and when they cross higher obstacles.
2005-06-14
Technical Paper
2005-01-2689
Norman I. Badler, Jan Allbeck, Seung-Joo Lee, Richard J. Rabbitz, Timothy T. Broderick, Kevin M. Mulkern
The earliest Digital Human Modeling systems were non-interactive analysis packages with crude graphics. Next generation systems added interactivity and articulated kinematic human models. The newest systems use real-time computer graphics, deformable figures, motion controllers, and user interfaces. Our long-term goal is to free the user as much as possible from interactive human model manipulation through direct understanding and execution of task instructions. We present a next generation DHM testbed that includes a scriptable interface, real-time collision-avoidance reach, empirical joint motion models, a versatile locomotion engine, motion capture and synthetic motion blends and combinations, and a smooth skinned scalable human model.
2005-06-14
Technical Paper
2005-01-2686
Kimberly Farrell, Timothy Marler, Karim Abdel-Malek
In the field of human modeling, there is an increasing demand for predicting human postures in real time. However, there has been minimal progress with methods that can incorporate multiple limbs with shared degrees of freedom (DOFs). This paper presents an optimization-based approach for predicting postures that involve dual-arm coordination with shared DOFs, and applies this method to a 30-DOF human model. Comparisons to motion capture data provide experimental validation for these examples. We show that this optimization-based approach allows dual-arm coordination with minimal computational cost. This new approach also easily extends to models with a higher number of DOFs and additional end-effectors.
2005-06-14
Technical Paper
2005-01-2687
Natsuki Miyata, Makiko Kouchi, Masaaki Mochimaru, Katsuaki Kawachi, Tsuneya Kurihara
Characterization of the human hand motion necessary to manipulate hand-held equipment requires accurate capture and reconstruction of the arbitrary subject's hand motions with respect to the object. The present study used an individual link structure modeled from optical motion capture data to perform this task and compared the results against those obtained by medical imaging. Posture data was captured while grasping several cylinders, and the captured data were utilized to generate new postures to grasp cylinders of arbitrary diameter.
2005-06-14
Technical Paper
2005-01-2684
Mickaël Hetier, Xuguang Wang, Frederic Robache, Barbara Autuori, Hervè Morvan
This paper presents the first experiment managed within the framework of the regional French project ST2 (French acronym for Sciences and Technologies for Safety in Transports). This program aims to study human pre-crash behavior in order to improve the efficiency of passive safety protection systems. An experiment was carried out using a driving simulator of LAMIH for investigating drivers frontal pre-crash postural changes. A scenario of an unavoidable crash was designed. To increase the level of realism during the crash, a real impact was added between the windscreen and a foam rubber block in addition to a truck horn sound. Risk car driver postures just before a frontal crash have been determined. The results have shown that none of the subjects adopted the standardized driving position during the collision and 30% of the subjects adopted a position with the left hand placed in front of steering wheel which can be considered as a risk position.
2005-06-14
Technical Paper
2005-01-2685
Liming Zhao, Ying Liu, Norman I. Badler
Simulating human reach is still challenging when considering complex interactions with the environment. Standard approaches involve inverse kinematics (IK) methods and usually require a complete but exponential cost search in configuration space. In ergonomic applications, both “naturalness” and interactive performance are important. We describe a real-time, collision-free, sternum-rooted IK solution for an articulated human figure based on motion capture data, human strength models, and multi-joint coordination functions. Movement paths are discovered through spatial search in a partitioned workspace. The system generates natural collision-free reach motions in real-time. The resulting animations and statistics demonstrate the efficacy of this approach.
2005-06-14
Technical Paper
2005-01-2682
Dominique Lestrelin, Jules Trasbot
The constraints applied to the design of cars and of other transportation systems imply space-restricted environments for their customers and/or manufacturing or maintenance workers. Consequently, some actions such as getting in and out of a car, or reaching the safety-belt, or loading/unloading the luggage compartment, can be difficult for some customers. For that reason, the designers need CAD-tools to be able to simulate not only the probable postures but the behaviour and movements of these persons, and to assess their discomfort in these situations, taking into account the suppleness- and force-capabilities of the real people, including senior citizens. Considering these needs, and not satisfied by the existing software and available databases, Renault built a proposal for a European Project called REAL MAN. This project started in the last quarter of 2001 and ended by mid-2004.
2005-06-14
Technical Paper
2005-01-2683
Katsuaki Kawachi, Kei Aoki, Masaaki Mochimaru, Makiko Kouchi
This paper proposes a method for visualizing and classifying the variation in the motions of a person when entering a passenger vehicle. Entering behaviors vary greatly between individuals, especially if the vehicle door is designed to have large clearance. The present study was conducted with the aim of supporting the design process of seats and front doors by visualizing possible variations of entering motions using a motion database, rather than calculating a single representative movement. The motion database is consist of different motions caused by various seats, and the motions are classified by mapping them into two-dimensional plane according to the similarities between them. A representative entering motion for a clustered motion strategy group is synthesized and visualized on the 2D distribution plane by interpolating existing motions in the database.
2005-06-14
Technical Paper
2005-01-2680
R. Timothy Marler, Salam Rahmatalla, Meagan Shanahan, Karim Abdel-Malek
Using multi-objective optimization, we develop a new human performance measure for direct optimizationbased posture prediction that incorporates three key factors associated with musculoskeletal discomfort: 1) the tendency to move different segments of the body sequentially, 2) the tendency to gravitate to a comfortable neutral position, and 3) the discomfort associated with moving while joints are near their respective limits. This performance measure operates in real-time and provides realistic postures. The results are viewed using Santos™, an advanced virtual human, and they are validated using motion-capture. This research lays groundwork for studying how and why humans move as they do.
2005-06-14
Technical Paper
2005-01-2681
David W. Wagner, Matthew P. Reed, Don B. Chaffin
For many industrial tasks (push, pull, lift, carry, etc.), restrictions on grip locations and visibility constrain the hand and head positions and help to define feasible postures. In contrast, foot locations are often minimally constrained and an ergonomics analyst can choose several different stances in selecting a posture to analyze. Also, because stance can be a critical determinant of a biomechanical assessment of the work posture, the lack of a valid method for placing the feet of a manikin with respect to the task compromises the accuracy of the analysis. To address this issue, foot locations and orientations were captured in a laboratory study of sagittal plane and asymmetric manual load transfers. A pilot study with four volunteers of varying anthropometry approached a load located on one of three shelves and transferred the load to one of six shelves.
2005-06-14
Technical Paper
2005-01-2678
Bastian Marx, Christian Amann, Murielle Verver
This study deals with the usability of the newly developed MADYMO human models for seat development. Three models consisting of FE-buttocks, SAE H-point mannequin and multi-body 50th percentile occupant model were used to predict the static and dynamic behavior of a man on a car seat, i.e. pressure distribution, H-Point position and behavior under vertical vibrations. Part of the investigation was also an FE seat model especially adapted to seating comfort referring to a medium-class BMW vehicle. On the same basis, hardware tests have been performed at BMW to compare the results with the simulation runs. As a result, it shows that it is possible to get usable seat pressure distributions and h-point values with the models, whereas an improvement of the foam model seems necessary to get reliable transmissibility data.
2005-06-14
Technical Paper
2005-01-2679
John N. Howell, Robert L. Williams, Robert R. Conatser, Janet M. Burns, David C. Eland
The Virtual Haptic Back (VHB) is designed as an aid to teaching medical palpatory diagnosis. It uses two PHANToM 3.0 haptic interfaces (SensAble Technologies, Inc.), permitting palpation by force feedback with two fingers of a life-sized virtual human back. A graphics image of the back is displayed on a monitor a few inches behind the palpable back. Movement of back components, e.g., skin or underlying vertebrae, by exertion of palpatory force by the user is reflected graphically. Mechanical properties of the back, e.g., spring constants of the surface, are chosen based on feedback from physicians experienced in palpatory diagnosis. Although subjective evaluation of the VHB by 81 users over 2 years is positive, results have not yet shown students being trained in palpatory diagnosis to perform better than controls subjects. Results guide modifications of the haptic model itself and of the user tasks employed during testing.
2005-06-14
Technical Paper
2005-01-2676
Xiaojiang Xu, Thomas L. Endrusick, William B. Santee, Margaret A. Kolka
Abstract A mathematical model utilizing the measured thermal resistance of footwear to predict toe temperature was developed. A lumped system represents the toe region as a single “toe” and a heat balance equation was established. The simulation was validated with measured physiological data obtained from human testing wearing the same footwear. The model prediction agreed with measured values within one standard deviation. The proposed approach, which consists of a heated thermal foot test and then modeling, is a cost effective alternative to human testing. The model has application for military planning, cold injury risk prediction and the selection of adequate protective footwear.
2005-06-14
Technical Paper
2005-01-2677
Brendan Ryan, Jin Wang, Christine M. Haslegrave
The aim of the current study was to construct a model of a road rail vehicle in JACK and investigate the view of the articulating arm of the machine for human models of different stature in test conditions simulating a digging task and a lifting task. The JACK software was also used to determine the likely effects on operator comfort of postural adjustments which would be required to see different parts of the articulating arm. Modelling of the tasks using JACK has been a useful first step in identifying the limitations in the field of view for vehicle operators of different statures. The use of the view cones in JACK have been evaluated and the simulations have highlighted the potential for discomfort arising from postural adjustments which would be necessary in the tasks. Further research on operators' postures and visual strategies during real world digging and lifting tasks is now necessary.
2005-06-14
Technical Paper
2005-01-2675
Matthew P. Reed, Kristy Satchell, Aris Nichols
The development of a new carrier route vehicle for the U.S. Postal Service began with the design of the vehicle interior from an operator-centered perspective. A task analysis of the postal worker while driving and while performing mail-handling operations guided the layout of the vehicle interior. The Jack™ human modeling software was used, along with SAE Recommended Practices and other tools, to create a vehicle environment that will accommodate a large percentage of the operator population. The challenges of designing for this unique work environment provided a good opportunity to evaluate the relative strengths and weaknesses of the available human factors tools, including the Jack™ digital human figure model. This paper describes the development of the vehicle interior, discusses some lessons learned, and concludes with recommendations for increased functionality and improved integration of vehicle interior design tools.
2005-06-14
Technical Paper
2005-01-2705
Mark de Zee, John Rasmussen, Jeroen Lem, Karl Siebertz
This study concerns the biomechanical computer simulation of the Active Motion system for car seats. This system can impose different kinds of small motions on the pelvis of the driver. Muscle activities were estimated for different parameters for the Active Motion using a musculo-skeletal model in the AnyBody Modeling System. The simulations suggest that a person using the Active Motion will not receive additional loads caused by the feature. Further, the Active Motion system might generate an average relative tension relief within a cycle up to 60 %. This avoids long-term static load, which might postpone or reduce discomfort. The average relative tension relief is most sensitive to pitch and roll amplitudes.
2005-06-14
Technical Paper
2005-01-2704
Gerri E. Archer, Michael Kolich
Digital human models have greatly enhanced design for the automotive driving environment. The major advantage of the models today is their ability to quickly test a broad range of the population within specific design parameters. The need to create expensive prototypes and run time consuming clinics can be significantly reduced. However, while the anthropometric databases within these models are comprehensive, the ability to position the manikins in a driving posture is limited. This study collected driving postures for occupants in two vehicle packages, a passenger car and utility-type vehicle. In all instances the occupant was instructed to adjust the vehicle parameters so they were in their most comfortable position. The posture of the occupants was then compared to postural output from RAMSIS and Catia V5 HumanBuilder.
2005-06-14
Technical Paper
2005-01-2703
Nicole Montmayeur, Christian Marca, Hyung-Yun Choi, Sungjin Sah
In order to assess the seating comfort design of a vehicle seat system, a full finite element occupant model, with anatomically precise features and deformable tissues, has been developed. This paper describes the experiments which were performed in order to assess the biofidelic accuracy of this model. First, static pressure distribution measurements, with human volunteers, have been performed. People of different morphological types were asked to sit on a PU foam cushion with various postures, which were captured by photographs and X-Ray measurements. Pressure sensors were used to determine the corresponding pressure distribution patterns. Then, the FE occupant model was used to simulate the same experiments, and the numerical results were compared to the experimental ones.
2005-06-14
Technical Paper
2005-01-2702
Ulrich Raschke, Hans Kuhlmann, Mike Hollick
A common request from users of human simulation tools is for functionality that allows rapid definition of task sequences and subsequent, largely automatic, “what if” scenario evaluation. A review of the high level requirements collected from feedback on our previous implementation forays of such systems is presented, and a new framework is suggested to address the broad set of identified requirements. The framework, called the Task Simulation Builder, is characterized by a flexible and extensible architecture centered around a learning type task controller. Minimum user input is required to describe a scenario of events and obtain a simulation output, yet through output refinement feedback, the resulting simulation can progressively be made as detailed as needed. The overall goal of the system is to improve the efficiency of human modeling use in production environments.
2005-06-14
Technical Paper
2005-01-2701
Brian F. Gore, Peter A. Jarvis
The Man-machine Integration Design and Analysis System (MIDAS) is an integrated human performance modeling software tool that is based on mechanisms that underlie and cause human behavior. A PC-Windows version of MIDAS has been created that integrates the anthropometric character “Jack™”1 with MIDAS’ validated perceptual and attention mechanisms. MIDAS now models multiple simulated humans engaging in goal-related behaviors. New capabilities include the ability to predict situations in which errors and/or performance decrements are likely due to a variety of factors including concurrent workload and performance influencing factors (PIFs). This paper describes a new model that predicts the effects of microgravity on a mission specialist’s performance, and its first application to simulating the task of conducting a Life Sciences experiment in space according to a sequential or parallel schedule of performance.
2005-06-14
Technical Paper
2005-01-2700
Wajih Bouslimi, Mohamed Kassaagi, Domitile Lourdeaux, Philippe Fuchs
Setting up a digital driver behavior model represents one major approach to design and validate active safety devices during their development phase. The present contribution introduces our predictive model of driver actions on car controls (steering wheel and pedals). Its core is based on the combined use of neural networks and genetic algorithms. This model was set up using a behavioral database gathered from a test track experiment. This paper details the different stages followed to construct our model. It shows validation results using another database and discusses its effective robustness.
2005-06-14
Technical Paper
2005-01-2699
Wei Shao, Demetri Terzopoulos
We present a technique for modeling large-scale urban environments for virtual human simulation. Our approach, which involves a set of hierarchical data structures, supports the efficient interaction between numerous autonomous pedestrians and their environment, including perceptual processing and path planning for the purposes of goal directed navigation. As a specific implementation of our approach, we develop an environmental model of a large train station and demonstrate its ability to support the real-time simulation of more than a thousand autonomous pedestrians engaged in a broad variety of individual and group behaviors appropriate to their large-scale urban environment.
2005-06-14
Technical Paper
2005-01-2698
Brett Walters, Julie Bzostek, Jia Li
Engineers often use different types of modeling and simulation to test crew station prototypes. A variety of tools exist to perform these types of analyses each with their own advantages. However, using these tools can be time-consuming and quite difficult, especially when engineers try to utilize the output of one tool as the input to another. The Crew Station Design Tool (CSDT) attempts to simplify this process by integrating three different software tools: 1) Micro Saint Sharp - a task network modeling tool, 2) Open Inventor™ - a three-dimensional graphics environment, and 3) Jack® - an anthropometric (human figure) modeling tool. The CSDT allows engineers to visualize and optimize their choices of controls and displays, and the position of those elements in a workstation. It automatically (and objectively) determines the optimum arrangement of controls and displays based upon sound human engineering and ergonomic principles.
2005-06-14
Technical Paper
2005-01-2697
Giuseppe Andreoni, Daniele Cremona, Andrea De Crescenzo, Roberto Viganò
This work deals with the definition of a virtual approach to the ergonomic analysis of the installation of a bulky technical product. Both the weight and the size could create difficulties to the users managing it during the transport, unpacking, and installation phases. This study is developed over two steps: the first step regards the execution of laboratory tests to carry out a physical description of the movement required to manage the product. Based on the results of the first step, in the second phase a virtual simulation of the movement required for the product installation is realized. Once terminated both the physical and the virtual tests, the results from the two models are compared to verify the correspondence of the virtual model with the real one through the comparison of a typical ergonomic parameter for lifting task that is the measure of the forces on the L4 and L5 inter-vertebral disk of the subject executing the test.
2005-06-14
Technical Paper
2005-01-2695
Thomas Alexander, Stephen R. Ellis
Motion is not only essential for interacting with the environment but also for its understanding. It has many facets which go beyond simply reaching a goal. Motion information often serves as the basis for inferring interrelationships between events, states and intentions of an acting entity. Observers can often identify persons from afar from their movement alone with only a low resolution view. In this connection it is important to identify dominant factors influencing this sensation. It would also be important to analyze how this understanding of motion relates to our primarily technological, cybernetic understanding of the structure of motion. This paper addresses some issues in this field. By emphasizing the compositional aspect of motion it extends the common technological structuring approach into another dimension. It does not offer a solution but serves as a basis for further discussions. At a first step, a linguistic approach is used for structuring complex motion.
2005-06-14
Technical Paper
2005-01-2694
Thomas Seitz, Daniele Recluta, Dominik Zimmermann, Hans-Joachim Wirsching
Today, there exist several methods to compute a realistic human posture depending on tasks and geometries, with which a human being is interacting. Several approaches use probabilistic models in combination with inverse kinematics. These methods produce acceptable results concerning the reliability and accuracy. However, they are unsatisfying in terms of flexibility concerning application to various tasks, since adapting a probabilistic model to new requirements needs a high technical measurement effort. Another disadvantage is that it is challenging to derive values like strain and workload respectively or discomfort from these approaches. Hence we have developed an approach for 1) computing autonomous postures, 2) assessing and considering joint load and 3) assessing discomfort. Integral part of this approach is an accurate physical description of test subjects.
2005-06-14
Technical Paper
2005-01-2693
Masaaki Mochimaru, Makiko Kouchi
The aim of this study was to develop a KANSEI model that estimates the impression ratings of various combinations of faces and spectacle frames. Such a KANSEI model can be used by a computer system at a retail shop to recommend a suitable frame, using physical characteristics of a consumer's face and spectacle frames. We selected 14 KANSEI words (e.g., “cheerful,” “intelligent") to describe the impression of each face/frame combination. We generated 96 CG images (8 representative face models × 12 frames). These images were shown to 75 female observers (students at a women's university), and impression ratings for 14 KANSEI words were obtained for each image using visual analog scales. Results of ANOVA indicated significant inter-face and inter-frame variance (p<0.01) for 11 KANSEI words. Thus, we have developed a computational model for estimation of impression ratings from physical characteristics of faces and frames.
2005-06-14
Technical Paper
2005-01-2692
Jason C. Olmstead Muhs, Jingzhou Yang
This paper presents a path prediction model for obstacle avoidance. A geodesics model is used to obtain the desired path in Cartesian space. The distance between the start target point (and end target point) and the surface of an obstacle is minimized to determine the boundary points of a geodesic across the surface of the obstacle. The model then numerically solves for a geodesic curve between the two boundary points of the geodesic on the surface of the obstacle. The model offsets the resulting discrete points on the geodesic in the positive normal direction (outside of the obstacle) to form a path of motion around the obstacle.
2005-06-14
Technical Paper
2005-01-2691
Q. Wang, Y.-J. Xiang, H.-J. Kim, J. S. Arora, K. Abdel-Malek
Simulating human motion is a complex problem due to redundancy of the human musculoskeletal system. The concept of task-based motion prediction using single- or multi-objective optimization techniques provides a viable approach for predicting intermediate motions of digital humans. It is shown that task-based motion prediction is in fact a numerical optimal control problem. Alternative formulations for simulation of human motion are possible and can be solved by modern nonlinear optimization methods. Three techniques based on state variable elimination, direct collocation and differential inclusion are presented and compared. The basic idea of the formulations is to treat different combinations of the state variables, such as the joint profiles and torques or their parametric representations as independent variables in the optimization process.
2005-06-14
Technical Paper
2005-01-2690
Christian Mergl, Margit Klendauer, Claude Mangen, Heiner Bubb
In this paper a project is described on finding a relationship between discomfort and contact force distribution between human and seat. In the first step experiments were conducted to find correlations between pressure and discomfort. In the second step these findings were validated for long term discomfort. The gained knowledge provides the possibility to check the long term riding properties of a car seat by taking the pressure distribution which takes only a few minutes. Furthermore, pressure distributions which are computed by digital human models can be evaluated with this knowledge.
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