ARTC provides the techniques of developing Electric Power Steering (EPS) system prototype for high loading vehicles. Based on the torque sensor signal, the electronic control unit (ECU) calculates the required assistance torque and controls the assist motor to drive the nut through the belt. The nut then pushes the ball screw and the rack to steer the front wheels. The developed ECU prototype consists of a microcontroller unit (MCU), 48V MOSFET converter, Driver IC, and other components to control a 48V permanent magnet synchronous 3 phase motor (PMSM); the MCU performs the field oriented space vector control algorithm and the speed, loading, return, friction compensation control logics to provide the steering assistance. The ECU has a calibration interface which enables read and write access to variables and memory contents of the MCU at runtime via CAN bus (Controller Area Network).

1. Rated voltage: 48V
2. Rated current: 21A
3. Control frequency: 20kHz
4. Sinusoidal commutation: Field oriented , space vector pulse-width-modulation control
5. Control Logic: Basic assistance, speed, loading, return, friction, damping compensation

The EPS for high loading vehicles can be used in electric vehicles (EV), hybrid vehicles (HEV), internal combustion engine vehicles (ICE) and other automobiles which use rack-and-pinion steering mechanisms.

ARTC has established EPS technologies which include system integration, design and development of electronic control units, system control logic design, steering feel tuning, etc. The establishment can make domestic component manufacturers have capabilities of system integration and master the EPS system technology for higher steering load to improve product competitiveness.