Abstract: An active braking hierarchical control algorithm was proposed for electric power-assisted braking systems to meet the needs for automobile unified active braking. The control method was divided into three layers: the upper, the middle, and the lower layer control. The upper-layer control proposed a feedforward and feedback closed-loop control method of longitudinal deceleration to convert the vehicle's target deceleration into target pressure; The middle-layer control took the braking system pressure-current model as feedforward and the proportion−integration−differentiation (PID) control based on the target pressure segments as feedback to converse the target pressure into the target current of the electric booster power motor; The lower-layer control realized the accurate follow of the target current of the motor through pulse-width modulation (PWM) of the motor input voltages. The test results show that the maximum error of the active deceleration control is ± 0.3 m/s2 with a deceleration response time being less than 300 ms. Therefore, the control algorithm meets the automobile’s needs for unified active braking.

Key words: electric power-assisted braking system, active braking, hierarchical control, proportion integration differentiation (PID) control