Fractional power rate reaching law for augmented sliding mode performance

Abstract

Abstract High-frequency control switching, chattering, limits the practical application of sliding mode controllers. This paper proposes an enhanced reaching law, viz., Fractional Power Rate Reaching Law (FPRRL), for the design of sliding mode controllers to mitigate the chattering problem. Controller gains are selected to accommodate variations in switching function dynamically to prevent over-actuation near the sliding surface, which is the primary reason for chattering. Chattering mitigation is achieved without compromising other attributes of sliding mode control. Performance enhancements in the attributes, viz., reaching time, robustness, and reduced chattering magnitude have been established through the methodical analysis of the new reaching law. The proposed control strategy is then bench-marked with the state of the art reaching law methods through simulations by considering a twin-rotor MIMO system control problem.