Abstract: Electro-mechanical brake(EMB) system has the advantages of good dynamic property, rapid braking response and more accurate brake, but this system suffers from such problems as needing more sensors, complex control and high failure risk. To solve these problems, this paper introduces a fuzzy control strategy based on the vehicle slip-ratio for the EMB system on the basis of the core of the EMB system control, motor control and one of the important control purposes of the vehicle braking—achieving the optimal vehicle slip-ratio. The proposed control method does not require feedback signals of pressure sensors. The motor stall or not is determined by current mutations in eliminating of brake clearance. After the eliminating of brake clearance, in order to keep the adhesion between the ground and wheels around the maximum, the slip ratio achieved is sent into the fuzzy controller and generates a pulse width modulation signal to control the motor electromagnetic torque to get the optimal slip ratio. The braking process is no longer considered for the accuracy control of brake actuator’s clamping force. Controller, motor and actuator comprises a closed loop system. The reasonable of the fuzzy control strategy based on slip-ratio used in EMB is proved by simulation based on Matlab/Simulink. These made a good foundation for further research.

Key words: Brushless direct current motor, Electro-mechanical brake(EMB), Fuzzy control, Slip-ratio