Abstract:

A novel integrated-electro-hydraulic brake system(I-EHB), composed of electric motor, ball screw pair, secondary master cylinder, pedal simulator, pedal displacement sensor and hydraulic pressure sensor and so on, is presented to fulfill the requirements of automobile brake system. Thanks to time-lag effect and low control precision, influenced by friction nonlinear phenomenon within the hydraulic pressure control system of I-EHB, system model is simplified, the system is analyzed based on the Byrnes-Isidori normalized form method, and a reasonable and effective control algorithm, which based on feedforward-feedback control and friction compensation control algorithm, is used to control the system. Hardware-in-the-loop(HIL) test platform is build up. Experiments are carried out respectively on four conditions(target hydraulic pressure step input of different amplitude, triangle input and sinusoidal input of different frequency and pressure increasing or decreasing step input) to verify the adaptability of this control system. Experimental results show that, the system has a fast response speed and high control precision by using this control algorithm, and the system performance is improved significantly.

Key words: Byrnes-Isidori normalized form, feedforward control, friction compensation, hydraulic pressure control, sliding mode control, integrated-electro-hydraulic brake system