Abstract
A Steer-by-Wire (SBW) system has many merits for a hydraulic-power steering system. The SBW system can reduce fuel costs and improve the steering feel with controlling electric actuators. However, it is difficult to apply the SBW system in a real vehicle directly because of safety and difficulties of updating control gain. In this paper, the Hardware-In-the-Loop-Simulation (HILS) system was developed for the Electronic Control Unit (ECU) to control an SBW system. The HILS system is available for developing control logic before installing the ECU in a real vehicle. Initially, the mathematical modeling of an SBW was made to control motors. The HILS system is composed of a hydraulic actuator for the lateral force of tires in a real vehicle, a linking mechanism that is similar to a real steering system and an ECU controlling two motors. The ECU is composed of a 16 bit micro-controller and a Motor Control Unit (MCU). The main controller, that is, the real-time processor, controls the hydraulic actuator and outputs the state signals of the ECU. The control gain of the SBW motors could be updated directly for improving the steering feel and improving the vehicle maneuverability and stability by the HILS output. The ECU has confirmed its suitability before applying the SBW system to the real vehicle through a number of simulations with the HILS system. By using the HILS system, the control algorithm of the ECU in a hazardous environment could be performed easily without using a real vehicle.