Abstract: A decoupling electro-hydraulic brake system (EHB) with the form of "electric motor + reduction gear" is studied, and a pressure controller of master cylinder considering the critical nonlinear characteristics (friction, PV) is designed to cope with the pressure creeping, deadzone and oscillation. Based on the LuGre model, an adaptive pressure controller is designed to compensate for the friction. Faced with the issues with using the pressure-based closed-loop controller at the operating point of the dead zone of the system, a nonlinear control algorithm based on dead-zone compensation is adopted. Combining the advantages of the above two controllers, a joint controller based on LuGre-model feedforward compensation and dead-zone compensation is developed. The pressure of the master cylinder can be accurately controlled considering the key nonlinear characteristics of the system. The analysis of the time- and frequency-domain characteristics of each closed-loop system is verified via the co-simulations (AMESim&Simulink) and the hardware-in-the-loop tests (HIL). The pressure-tracking dynamic accuracy and response speed using the joint controller is improved by comparison tests.

Key words: pressure control of master cylinder, integrated-electro-hydraulic brake system(IEHB), friction, pressure-volume characteristic(PV), LuGre friction model, dead zone