ZMP Theory-based gait planning and model-free trajectory tracking control of lower limb carrying exoskeleton system

Abstract

A virtual prototype design and corresponding mathematical model analysis is presented. To obtain a stable and smooth synthesized gait, the zero-moment-point (ZMP) theory and three spline interpolation method have been combined and applied. A novel data-driven model free control strategy, called Time-Delay Estimation based intelligent PID (TDE- iPID) combined with Equivalent Sliding Mode Control (TDE-iPIDESMC), is developed for the trajectory tracking of the planned gait. To demonstrate the effectiveness of the proposed planning gait and controllers, the exoskeleton system is implemented on the co-simulation platform composing of Adams and MATLAB/Simulink. The corresponding cosimulation results show better performances than the compared classical PID and TDE-iPID methods.