New Capabilities for the Virtual-Human Santos™

Yang, Jingzhou; Marler, Timothy; Beck, Steve; Kim, J.; Wang, Q.; Zhou, Xianlian; Pitarch, Esteban Peña; Farrell, Kimberly; Patrick, Amos; Potratz, Jason; Abdel‐Malek, Karim; Arora, Jasbir S.; Nebel, Kyle

doi:10.4271/2006-01-0697

Cited by 9 publications

(5 citation statements)

References 21 publications

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“…Some further research in human motion prediction and simulation also includes comparison with other models now being used, and the consideration of collision avoidance in the formulations. A general framework for collision avoidance of human motions has been recently presented 35 .…”

Section: Future Researchmentioning

confidence: 99%

Alternative Formulations for Optimization-Based Human Gait Planning

Wang

Xiang

Arora

et al. 2007

48th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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Simulating human motion is a complex problem due to redundancy of the human musculoskeletal system. The concept of task-based dynamic motion prediction using singleor multi-objective optimization techniques provides a viable approach for predicting dynamic gait motions of digital humans, subjected to basic physical and kinematical constraints. The task-based motion prediction is in fact a numerical optimal control problem. Alternative formulations for simulation of human gait motion are possible and can be solved by modern nonlinear optimization methods. Different ways to discretize the equations of motion are presented, namely finite difference, and Hermite and B-spline interpolations. The advantages and disadvantages of different formulations are discussed. Since the human gait simulation utilizes gradient-based optimization techniques, analytical gradients of objective and constraint functions are provided. A skeletal model for the lower body having 18 degrees of freedom is used to demonstrate the formulations, and is solved by a large-scale sparse nonlinear programming solver.2 inverted pendulum. The advantages of this method are its simplicity and fast solvable dynamics equations 5 . However, it also suffers from an inadequate dynamics model that cannot generate natural and realistic human motion.Optimization-based trajectory generation is aimed at more realistic and natural humanoid motion. Many humanfeatured criteria can be simultaneously considered rather than only stability. For digital human simulations, the objective functions represent human performance measures, and optimization methods are used to solve for the feasible joint motion profiles that optimize the objective functions and satisfy the necessary constraints 6-9 . Lo et al. used quasi-Newton nonlinear programming techniques to determine the human motion that minimizes the actuating joint torques 10 . The design variables were the control points for the cubic B-spline approximation of joint angle profiles. Chevallereau and Aoustin planned a walking and running motion using the Pontryagin Maximum Principle to determine the coefficients of a polynomial approximation for profiles of the pelvis translations and joint angle rotations 6 . Saidouni and Bessonet solved for cyclic, symmetric gait motion of a nine degree of freedom (DOF) model that moves in the sagittal plane 8 . The control points for the B-spline curves along with the time durations for the gait stages are optimized to minimize the actuating torque energy. By adopting the time durations as design variables both the motion for the single support and for the double support are simultaneously optimized.Skeletal models are used quite naturally in the robotics area. They have also been used in human locomotion modelling due to their relative simplicity and computational efficiency 6-9 . In biomechanics literature, optimizationbased methods have been used to simulate human motion with complex musculoskeletal models [11][12][13] . Muscle groups are included in the model using Hill-type elem...

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Section: Future Researchmentioning

confidence: 99%

Alternative Formulations for Optimization-Based Human Gait Planning

Wang

Xiang

Arora

et al. 2007

48th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

View full text Add to dashboard Cite

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“…To satisfy this need, the US Army launched a research effort several years ago to develop Santos. Santos has a physical-based environment (Yang et al, 2004;Yang et al, 2006a;Yang et al, 2006b;Abdelmalek et al, 2006) and a human-like appearance. Because it is a muscularskeletal human model, it can answer different types of questions (e.g., whether Santos has enough energy to walk from Point A to Point B and, if so, what the discomfort level will be).…”

Section: Introductionmentioning

confidence: 99%

Newly Developed Functionalities for the Virtual Human Santos

Yang

Man

Xiang

et al. 2007

SAE Technical Paper Series

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This paper presents newly developed capabilities for the virtual human Santos TM. Santos is an avatar that has extensive modeling and simulation features. It is a digital human with 109 degrees of freedom (DOF), an optimization-based method, predictive dynamics, and realistic human appearance. The new capabilities include (1) significant progress in predictive dynamics (walking and running), (2) advanced clothing modeling and simulation, (3) muscle wrapping and sliding, and (4) hand biomechanics. With these newly developed functionalities, Santos can simulate various dynamic tasks such as walking and running, investigate clothing restrictions to motion such as joint limits and torques, simulate the musculoskeletal system in real time, predict hand injury by monitoring the joint torques, and facilitate vehicle interior design. Finally, additional ongoing projects are summarized.

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“…In this paper, we present newly developed facets of an optimisation-based avatar called Santos that promises to be the next generation of virtual humans (Yang et al, 2005(Yang et al, , 2006a. The work presented in this paper is part of an ongoing project to develop a system in which an avatar's motion is governed by a variety of human performance measures that are incorporated in a novel optimisation-based approach to posture and motion prediction.…”

Section: Introductionmentioning

confidence: 99%

Towards a new generation of virtual humans

Abdel‐Malek¹,

Yang²,

Marler³

et al. 2006

IJHFMS

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This paper presents work from an ongoing project towards developing a new generation of virtual human models that are highly realistic in appearance, movement, and feedback. Santos TM , an anatomically correct human model with more than 100 degrees of freedom, is an avatar that exhibits extensive modeling and simulation capabilities, resides in a virtual environment, and conducts human-factors analysis. The paper presents an optimisation-based approach to posture and motion prediction that allows the avatar to operate with autonomy rather than depending on stored animations and data or being restricted by inverse kinematics. It also presents approaches to determining reach envelopes and workspace zone differentiation, and discusses methods for evaluating the physiological status of the virtual human as it completes tasks. Muscle modeling including muscle wrapping, muscle force and stress determination is also discussed. Finally, the process of building a 25-DOF hand model is described. The result is an exciting step towards a virtual human that is more extensive and complete than any other.

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New Capabilities for the Virtual-Human Santos™

Cited by 9 publications

References 21 publications

Alternative Formulations for Optimization-Based Human Gait Planning

Alternative Formulations for Optimization-Based Human Gait Planning

Newly Developed Functionalities for the Virtual Human Santos

Towards a new generation of virtual humans

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