Fixed‐time velocity‐free coordination control for human‐robot systems without any approximation function

Abstract

AbstractIn this paper, the fixed‐time coordination control problem is addressed for a class of uncertain human‐robot systems without velocity information. Specifically, due to the absence of approximation function, the developed control scheme is more practical. Firstly, a new fixed‐time velocity observer is introduced to estimate unmeasured velocities with the homogeneity theory. Then, the performance of the velocity observer in the presence of parametric uncertainties and non‐parametric uncertainties is analyzed seriously. Furthermore, a novel distributed continuous fixed‐time control (DCFTC) scheme is proposed. Compared with the existing velocity‐free controllers, fixed‐time convergence is achieved both for velocity estimation and trajectory tracking. More than that, distributed control is realized by using graph theoretic notions. Finally, numerical simulation results and experiment results demonstrate the efficacy and superior performance of the proposed velocity estimation method and control algorithms.