OPTIMIZED CONTROLLER DESIGN FOR A C-EPS ELECTRIC POWER STEERING SYSTEM IN CARS

Abstract

Currently, electric power steering systems are being used very commonly on
modern cars. In this paper, the authors focus on studying the electric power
steering system with a power steering motor mounted on the steering colum
(C-EPS), thereby building a model, setting up the dynamics and express in state-
space reprentation. The authors use the optimal control method LQR to simulate
and evaluate with the input signal being the disturbance from the driver and the
road surface; the control signal is the voltage of the electric power steering motor.
Simulation results in the time domain show that when the electric power steering
system uses the optimal controller LQR, the torque from the driver acting on the
steering wheel is reduced from 20 to 25% compared to the torque acting by using
passive system but it still ensures the car's trajectory. This shows that cars can
change the trajectory more easily and gently when using the electric power
steering system with the optimal controller LQR.