Hydraulic-pressure-following control of an electronic hydraulic brake system based on a fuzzy proportional and integral controller

Abstract

Significant nonlinearity of electronic hydraulic brake (EHB) systems often leads to complex hydraulic force control responses. This paper designs a motor-driven EHB system and analyzes nonlinear friction induced by the deceleration mechanism. To compensate this friction, a flutter signal is added to the controller input. In addition, this paper designs a fuzzy-PI (Proportional and Integral) controller for the cylinder hydraulic pressure of the EHB system based on the opening and closing characteristics of a solenoid valve. Response curves of cylinder hydraulic pressure are obtained under three different input signals: step, triangular, and sinusoidal. The co-simulation model is established by AMEsim™ and Simulink® ansofts. The study results indicate that the proposed hydraulic-force-following control method of the EHB system can follow different input signals well. A step response test and a sine-wave-following test are carried out, which correspond to the EHB response in the case of driver’s emergency braking and frequent braking, respectively. Stable and rapid pressure build-up is obtained under different step target hydraulic pressures. Therefore, the hydraulic-force-following control method of the EHB system based on a fuzzy-PI controller can satisfy the EHB system accuracy requirements for an electric vehicle, which is a certain valuable for the automobile industry.