Fuzzy PID Control In Electric Steering Engine For Nonlinear Factor

As an important part of aircraft control system, Steering gear decide the dynamic performance in the process of fly.Nonlinear factors such as friction and backlash is one of the important factors that affect the steering gear system dynamic and static performance. Due to the existence of the backlash, the system may produce reverse error when reversing, what will affect the tracking precision of servo system.But the backlash is a inevitable phenomenon in the mechanical structure, and eliminate the backlash will increase the complexity and difficulty.The purpose of this research is aimed at a certain missile electric steering gear which adopts brushless dc motor, reduce the interference of the backlash in the system to a minimum through control algorithm to a minimum.To improve the control accuracy of the electric steering gear system under the factor, this research mainly do the following:Based on the characteristics of fuzzy control algorithm that is not sensitive to disturbance and have strong robustness, design the fuzzy PID controller based on the theory of fuzzy, complete the position loop to track the implementation of electric steering gear system.At the same time in order to solve the big impact in the system that fuzzy control rules set artificial, introduce the adaptive principle to improve the control accuracy.To test and verify the feasibility of algorithm, set up the simulation model of the steering gear system based on the simulink platform structure, simulate the algorithm and compare with the conventional PID algorithm. Simulation results show that compared with the conventional PID controller, the adaptive fuzzy PID controller have high control precision, fast response, less overshoot, and reduce the influence of nonlinear factors interference.In terms of hardware platform, according to the characteristics of the electric steering gear system, this research choose the DSP as the core of multiple bus control system based on CAN2.0 and SCI, realize the accurate control and data real-time transmission of servo system. In the aspect of control algorithm, to simplify the programming, the method is based on model design which save a lot of design time.Finally, the hardware platform and software environment to complete, go on step and sine tracking test respectively with conventional PID controller and the adaptive fuzzy PID controller in electric steering gear after complete the hardware platform and software environment, to verify the feasibility of the control strategy and the performance of the controller.