Modeling and optimization of human walking

Abstract

In this paper we show how optimal control techniques can be used to generate natural human walking motions in 3D. Our approach has potential applications in humanoid robotics, biomechanics and computer graphics. It has the advantage that it does not require any previous knowledge about walking motions from experiments. In this study we consider symmetric walking along a straight line, but the same techniques can be used to generate walking motions along curved paths or asymetric motions.We establish a multibody model of the human body with twelve segments including a head, a three-segment trunk, and arms and legs with two segments each. An optimal control problem is formulated that minimizes joint torques head movement, and the impulse on touch-down in a combined criterion. The dynamics of the multi-body system are considered as constraints to the optimal control problem to guarantee physically feasible motions. The optimal control problem is solved using an efficient direct multiple-shooting method. A skeletal animation library is used to present the results of the optimized motion.