Development of human lower extremity kinematic and dynamic models for exoskeleton robot based physical therapy

Abstract

The World Health Organization reports that approximately one billion people are disabled in the world. Exoskeleton robot-based physical therapy is an appealing solution for a large number of disabled people. Mechanical design, modelling, and control of exoskeleton robots require anthropometric data. A majority of anthropometrical data is not readily available from a single source. Furthermore, seven degrees of freedom human lower extremity kinematic and dynamic models are also not available. This paper presents dynamic modelling and simulation of the human lower extremity. The dynamic simulation utilises a computed torque controller (CTC). A sliding mode controller (SMC) is also developed for practical applications. Simulation results show the performance of the controller, joint torque, and power requirements for tracking a specified trajectory. Because of its performance in the presence of simulated disturbances and parameter variations, it is seen that the SMC is an effective choice for controlling a real robot.