Fuzzy robust trajectory tracking control of WMRs

Abstract

Using intelligent robust controllers, perfect trajectory tracking of nonholonomic wheeled mobile robots (WMRs) is developed. A feedback linearizable computed torque controller (FLCTC) may be used to make the convergence of a WMR on preplanned trajectories. Owing to the weak performance against exogenous signals, the FLCTC is replaced by a sliding mode controller (SMC) based on a proportional integration derivative (PID) sliding surfaces. The proposed SMC though results in a robust tracking performance against exogenous inputs as well as model uncertainties; the chattering phenomenon originated from the characteristic of the sign function is unavoidable. As a well-known technique, the sign term could be replaced by a saturation kind which could not remove the high range chattering of tracking errors. Therefore, using the expert knowledge and experiences in the field of WMRs, a Mamdani type fuzzy SMC (FSMC) is designed to perfect trajectory tracking without considerable chattering effects. The asymptotic stability of the proposed control systems is investigated based on the Lyapunov's direct method. Furthermore, the superiority of the proposed pure and Fuzzy SMCs to the recent FLCTC is revealed through software simulation results. © 2012 Springer Science+Business Media, LLC.