Adaptive Fixed-time Acceleration Reconstruction Scheme for Exoskeleton System with Error Constraints

Abstract

Abstract Acceleration acquisition is a key issue in robotic exoskeleton system, which is, however, hard to acquire directly via existing sensing system. To this end, a novel adaptive fixed-time acceleration reconstruction scheme with error constraints is proposed for a class of exoskeleton systems. In this approach, a new barrier Lyapunov function is proposed to address the reconstruction error constraints. Together with exponential-type Lyapunov function, contraction factors concept is put forward to ensure the observation errors are limited within prescribed constraints. Moreover, the convergence time is irrelevant to initial states or external disturbance but only dependent on the chosen parameters. Simulation results demonstrate the performance of fixed-time and guaranteed constraint convergence.