Fault Tolerant Controller Design for a Faulty UAV Using Fuzzy Modeling Approach

Moshu Qian,Lili Wang,Ke Xiong,Zhongmin Qian

doi:10.1155/2016/5329291

Abstract

We address a fault tolerant control (FTC) issue about an unmanned aerial vehicle (UAV) under possible simultaneous actuator saturation and faults occurrence. Firstly, the Takagi-Sugeno fuzzy models representing nonlinear flight control systems (FCS) for an UAV with unknown disturbances and actuator saturation are established. Then, a normal H-infinity tracking controller is presented using an online estimator, which is introduced to weaken the saturation effect. Based on the normal tracking controller, we propose an adaptive fault tolerant tracking controller (FTTC) to solve actuator loss of effectiveness (LOE) fault problem. Compared with previous work, this approach developed in our research need not rely on any fault diagnosis unit and is easily applied in engineering. Finally, these results in simulation indicate the efficiency of our presented FTC scheme.

Highlights

unmanned aerial vehicle (UAV) is a class of aircraft without a human pilot onboard
A fault tolerant control (FTC) approach based on Mathematical Problems in Engineering an observer is proposed for a T-S fuzzy model with actuator loss of effectiveness faults in [7]; it guarantees the stability of a controlled object in actuator faulty case
We focus on the fault tolerant tracking controller (FTTC) design for nonlinear flight control systems of UAV under unknown disturbances, actuator saturation constraints, and actuator loss of effectiveness (LOE) faults

Summary

Introduction

UAV is a class of aircraft without a human pilot onboard. The flight of an UAV, depending on flight control systems that include actuator, sensor, and so on, is controlled autonomously either by onboard computers or by the remote control of a pilot [1]. Some results about fault accommodation for fuzzy control system have been achieved in recent years, the FTC problem in an actual control system still exists and needs solving; for example, the FTTC design of a Takagi-Sugeno fuzzy system under disturbance, actuator loss of effectiveness (LOE) faults, and saturation simultaneously is a challenging public problem now. We focus on the FTTC design for nonlinear flight control systems of UAV under unknown disturbances, actuator saturation constraints, and actuator LOE faults. (1) Actuator saturation constraints and unknown disturbances represented by T-S fuzzy model are considered; the adaptive approach can guarantee asymptotic tracking control performance of the nonlinear closeloop flight control systems. Simulation results show that our design approach has the favorable fault tolerant capability and robust ability

Problem Formation

Main Results

Illustrative Example

Conclusion