Analysis On EPS Machitrical Dual Closed-loop Control System

The electric power steering system (EPS) is a combination of mechanical and electrical control system. EPS'control strategy used commonly has two kinds: current PID control and fuzzy control. The current PID control based on the difference between target current and feedback current is a curren closed-loop control system and the fuzzy control is a mechanical closed-loop control system based on the difference between forces of the upper part and the lower part of the steering shaft. Taking the margin of the mechanical and electrical closed-loop control system, this paper, a torque feedback loop for the outer ring, a current feedback loop as the inner loop, designed a dual-loop control system, the output of the fuzzy control determined a target current, and then proceed to current PM control, fast-track the target torque. The simulation shows the dual closed-loop fuzzy PID control is superior to two commonly used control strategies so that electric power steering system has a better tracking ability and stability.