Robust Adaptive Control for Uncertain Input Delay MIMO Nonlinear Non-Minimum Phase System: A Fuzzy Approach

Zhiguo Liu,Yang Guo,Xiaoxiang Hu,Xin Wang

doi:10.1109/access.2020.3018163

Abstract

In this paper, the robust controller design problem of uncertain multi-input multi-output nonlinear non-minimum phase system is discussed. The nonlinear system is suffering from both uncertainty and input delay, so the controller design is difficult. The traditional stable inversion controller is utilized and extended to uncertain case. An integral of past control input is constructed and fuzzy logical system is utilized for approaching the unknown state matrix and input matrix. Then a robust adaptive control strategy is presented. Finally, a numerical simulation on vertical takeoff and landing aircraft is given to show the effectiveness of the proposed method.

Highlights

T HE dynamic characteristic of a practical servo system is often viewed as a linear function, while the real dynamic characteristic is really complex
To reduce the conservative of the designed controller, diffeomorphism coordinate transformation (DCT) based controller design methods are proposed for input delay nonlinear system
Through choosing appropriate DCT, the original nonlinear system is simplified, and lots of controller design strategies, like back-stepping method [23], [34], [35], sliding mode control [32] and adaptive neural network method [18] are proposed for the input delay nonlinear system

Summary

INTRODUCTION

T HE dynamic characteristic of a practical servo system is often viewed as a linear function, while the real dynamic characteristic is really complex. The methods for input delay nonlinear system directly are all based on an assumption that, the nonlinear model can be completely linearization, or its internal dynamics are stable. The output tracking control of non-minimum phase system has been widely studied, and ideal internal dynamics (IID) based controller method is a widely used [10]. Motivated by the reasoning above, control design of uncertain input delay MIMO nonlinear non-minimum phase system is considered here, and a FLS based control design method is discussed. The robust output tracking control for VTOL with both uncertainties and unmodelled disturbance has not been completely solved In this case, an adaptive robust controller design method is considered in this paper, and a numerical simulation is listed to confirm its’ effectiveness. Y1d(r1), y2d(r2), · · · , ym(rm) represents r order differential of the given command, d is the linearization error, A=

Bς Bη

BT Pe

CONCLUSIONS