Command filtered robust backstepping control with an error dynamics based nonlinear disturbance observer for nonlinear systems

A command filtered robust backstepping control (BSC) scheme for a nonlinear system is studied in this paper. To avoid the repeated differentiation of the conventional BSC system, the command filter is introduced and newly defined auxiliary error surface is considered to obtain robustness to uncertainty. Based on this error surface dynamics, a nonlinear disturbance observer is constructed to estimate uncertainty due to perturbation and external disturbance. The stability of the closed-loop system for the designed controller, observer, and compensating signal is proved by the finite-time Lyapunov theorem. The efficacy of the proposed control system was evaluated by simulations of two nonlinear example systems. © ICROS 2020.