Research on Master Cylinder Pressure Control of Electro-Hydraulic Braking System

Addressing the critical challenges of low accuracy, response hysteresis, and insufficient adaptability to complex dynamic tracking conditions in the pressure buildup control strategy of the Electro-Hydraulic Brake system (EHB), this paper proposes a cascaded multi-loop control algorithm based on Active Disturbance Rejection Control (ADRC) and Sliding Mode Control (SMC). Specifically, an ADRC–based integrated position–speed controller is designed to simultaneously analyze the influence of motor speed and piston displacement, thereby mitigating the issue of performance degradation and simplifying the observation of internal system states. Furthermore, the pressure loop utilizes a feedforward-based SMC algorithm tailored to the strong nonlinearity and significant interference characteristics of the hydraulic–mechanical coupling. A joint simulation platform based on Matlab/Simulink and AMESim was established, followed by validation through vehicle tests on a One-box experimental vehicle under step, sinusoidal, and ramp pressure signals. Simulation results indicate that the steady-state pressure error is maintained below 0.1 MPa. Crucially, real vehicle tests demonstrate steady-state errors within ±0.2 MPa (ramp) and ±0.5 MPa (sinusoidal), with maximum dynamic tracking errors kept below 0.8 MPa and 1.2 MPa, respectively. These findings comprehensively verify the advantages of the proposed strategy in terms of response speed, steady-state accuracy, reliability, and robustness.