Study On EPS Control Strategy Based On H_∞ Robust Control Theory

In this Dissertation, the running mechanism of automotive EPS (Electric Power Steering) system is studied, to reveal that the EPS system control problem is essentially attributable to many control objectives, multiple-input multiple-output (MIMO) robust control problem with a certain amount of non-linear, time-varying non-uncertain systems. With modern robust control theory and technology, the EPS system dynamics state-space model is set up. The robust expression of the control EPS is discussed to give the judgement qualification of robust stability and robust performance. Then, H∞controller of EPS mixed sensitivity is designed. The following characteristics of EPS control system applied by Hm controller is studied by simulation to propose H∞control strategy of EPS road feel intensity. Virtual laboratory of automobile EPS based on Proteus and Keil software is built. Based on the simulation results of EPS driver software and hardware in the virtual laboratory, the composition, overall program, experimental project design and development of key technologies of the automobile EPS test bed and the development of EPS measuring board are studied. Finally self-developed EPS which got good performance on test bed of EPS is installed in test car to conduct a comprehensive performance evaluation of the road vehicle. Research findings applied by practice show that the car EPS based on the Hm controller can effectively find the LMI convex optimization point to provide timely assistance force in time, so self-developed EPS is with intelligence, practicality and reliability.