Higher order sliding mode control applications with output redefinition for nonminimum phase missile system

Abstract

In this work higher order sliding mode autopilots are designed for highly maneuverable nonminimum phase missile system. Nonminimum phase nature of tail controlled missiles prevents direct implementation of sliding mode control algorithms. To overcome this difficulty an output redefinition technique is developed. Then higher order sliding mode control algorithms used for autopilot design. Second and third order SMC algorithms are tried on missile system that ideally has relative degree of two. It is showed that parasitic input-output dynamics that have lower relative degree than ideal input-output dynamics have disruptive effect on control performance. Solution is found by increasing of order of the controller and generating control signal as derivative of input. Finally adaptation schemes are applied to control algorithms to reduce chattering and increase convergence rate. Results of numerical simulation runs are given to show the effectiveness of the proposed control applications.