Adaptive Robust Control and Optimal Design for Fuzzy Unmanned Helicopter Tail Reduction

This paper develops an adaptive robust control scheme combined with optimal design for the unmanned helicopter tail reduction (UHTR) system. The dynamical model of the UHTR system with uncertainties is established. The uncertainties are assumed to be bounded and expressed by fuzzy set theory. With this prerequisite, an adaptive robust controller is proposed to drive the system to meet the trajectory requirements approximately. The adaptive law with leakage and dead zone is performance based and flexibly adjustable. By means of Lyapunov stability theorem, the UHTR system is both uniform bounded and uniform ultimate bounded with the proposed controller. The control scheme is deterministic rather than fuzzy if-then rules-based control. Moreover, the fuzzy performance index which contains the steady-state system performance and control cost is presented. In this way, the optimal design problem can be replaced by minimizing the performance index. Overall, the resulting control scheme can guarantee deterministic performance of the UHTR system and minimize the fuzzy performance index simultaneously.