Model-Based Pressure Control for an Electro Hydraulic Brake System on RCP Test Environment 2016-01-1954
In this paper a new pressure control method of a modified accumulator-type Electro-hydraulic Braking System (EHB) is proposed. The system is composed of a hydraulic motor pump, an accumulator, an integrated master cylinder, a pedal feel simulator, valves and pipelines. Two pressurizing modes are switched between by-motor and by-accumulator to adapt different pressure boost demands. A differentiator filtering raw sensor signal and calculating pedal speed is designed. By using the pedal feel simulator, the relationship between wheel pressures and brake force is decoupled. The relationships among pedal displacement, pedal force and wheel pressure are calibrated by experiments. A model-based PI controller with predictor is designed to lower the influences caused by delay. Moreover, a self-tuning regulator is introduced to deal with the parameter’s time-varying caused by temperature, brake pads wearing and delay variation. To verify the controller validity, a Rapid Control Prototype (RCP) test environment based on dSPACE is built. Self-designed HCU and pedal feel simulator are installed in test bench. The close loop test results of pressure tracking are plotted and analyzed by contrasting normal PI controller and proposed controller. The conclusion indicates that the proposed controller can reach a balance of rapidity and accuracy, meanwhile the operating time and energy consumption are also reduced.