Adaptative Pressure Estimation and Control Architecture for Integrated Electro-Hydraulic Brake System

Abstract To meet the higher requirements intelligent and electric trend of automobile puts forward for brake-by-wire system, the master cylinder pressure estimation and control is the core technology that need to be researched and improved. Most of the existing research about master cylinder pressure control is based on pressure sensor equipped in it. In this scheme, the failure of pressure sensor will seriously affect the reliability and it is difficult to ensure pressure tracking speed and accuracy at the same time. This article proposes an adaptative pressure estimation and control architecture which is based on estimated pressure instead of pressure sensor for integrated electro-hydraulic brake system. About the master cylinder pressure estimation, we propose an adaptative fusion method which calculates the weights of estimator based on vehicle mode and electro-hydraulic mode according to master cylinder pressure, longitudinal speed and ABS status, the estimated pressure from fusion method finally is used to update the hydraulic mode of integrated electro-hydraulic brake system. According to the updated hydraulic mode, we can derive the final estimated pressure and update the coefficient of the friction mode. In addition, this article proposes an adaptative LQR controller for master cylinder pressure control which uses fuzzy-logic controller to adjust the weights of LQR controller based on target pressure and difference compared with actual pressure. At last, through Mode-in-Loop and Hardware-in-Loop tests, we compare the estimated pressure and actual pressure, pressure tracking results of Piecewise PID controller and that of adaptative LQR controller in ramp, step and sinusoidal response. Based on the analysis of experiment results, we can conclude that the proposed adaptative pressure estimation and control architecture can estimate MC pressure effectively in any scene and ensure the pressure tracking speed and accuracy at the same time.