Kinematic Analysis for Optimum Manipulability and Trajectory Planning of Human Leg

Abstract

Inverse kinematics and trajectory planning are important for rehabilitation robotics and exoskeleton design. In this paper, a three-link three-dimensional kinematic model of a human leg is defined and its kinematic analysis is performed with the focus of optimizing its manipulability. The biomechanics data is used to obtain the range of motion limit and comfort zone of every joint. The forward kinematics of the leg is used to obtain the workspace of the human leg. Using inverse kinematics, the final joint angles for the desired three-dimensional position are obtained. The inverse kinematics of human leg model is formulated as a constrained optimization problem to get the optimum joint angles under different task constraints. The fifth-degree polynomial function is used to obtain trajectory from initial to final joint angles. Simulations have been performed on the kinematic model of a human leg for workspace evaluation, inverse kinematic solution, and trajectory planning.