  Integrated electric parking brake (iEPB) is popularizing on passenger cars
due to its easier operation and automatic functions. As a parking brake, EPB
have to act as the secondary brake system in case of hydraulic brake failure.
To guarantee the stability and safety of a car during iEPB braking, the rear
slip ratio has to be controlled accurately within the optimized value to get
the shortest brake distance without undesired loss of control. In this paper, a
sliding-mode controller (SMC) is investigated to achieve rear-wheel anti-lock
brake control, which is robust against uncertainties and disturbance of the
parameters. And a sliding-mode observer (SMO) is present to estimate the load
torque of d.c. motor and calculate the brake torque. The tyre/road friction
coefficient estimator is designed to obtain the optimal rear slip ratio timely.
The simulation model of iEPB system is initially constructed in AMESim and the
vehicle model is built in MATLAB/Simulink, and the complete system is
co-simulated by these two software simultaneously with different road
conditions. Simulation results show that the proposed observer and estimator
are feasible. This study may provide a useful method to realize rear slip ratio
control so that the safety and stability of vehicle could be improved
significantly in specified condition
