Robust control of a class of non-linear cascade systems: a novel sliding mode approach

A novel robust control scheme based on a sliding-mode approach is proposed for a general class of nonlinear uncertain systems with saturation-bounded inputs. By introducing a new sliding variable as a complement to the conventional sliding variable, a useful error measure is defined from which a new sliding-mode controller is developed. This controller can give a closed-loop system with better error responses during the reaching phase and a smaller ultimate error bound when in the boundary layer. Without raising the stability issue, an anti-windup compensator is incorporated into the proposed control scheme to help counteract the input-saturated effect. The nonlinear benchmark problem "RTAC" (Rotational/Translational Actuators) was used as a simulated example to demonstrate the effectiveness of the design