Robust adaptive back-stepping control for nonlinear systems with unknown backlash-like hysteresis

In this paper, a robust adaptive control method based on back-stepping approach is presented to deal with adaptive control of a class of nth-order nonlinear systems with unknown backlash-like hysteresis and unknown external disturbance. The backlash-like hysteresis is modelled by a differential equation. The control algorithm can ensure the global stability of the nonlinear closed loop system and the actual output can track the reference output well. Two examples illustrate and verify the performance of the new proposed control scheme. This method may be used in the mechanical actuators, piezo-electric materials, and tendon sheath mechanism system.