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

Abstract The current research of master cylinder pressure estimation mainly relies on hydraulic characteristic or vehicle dynamics. But they are not independently applicable to any environment and have their own scope of application. In addition, about the master cylinder pressure control, there are few studies that can simultaneously balance pressure building accuracy, speed, and prevent pressure overshoot and jitter. In this paper, an adaptative fusion method based on electro-hydraulic characteristic and vehicle mode is proposed to estimate the master cylinder pressure. The fusion strategy is mainly based on the prediction performance of two algorithms under different vehicle speeds, pressures, and ABS states. Apart from this, this article also includes real-time prediction of the friction model based on RLS to improve the accuracy of the electro-hydraulic mode. In order to simultaneously balance pressure control accuracy, response speed, and prevent overshoot and jitter, this article proposes an adaptative LQR controller for MC pressure control which uses fuzzy-logic controller to adjust the weights of LQR controller based on target pressure and difference compared with actual pressure. Through mode-in-loop and hardware-in-loop tests in ramp, step and sinusoidal response, the whole estimation and control system is verified based on real hydraulic system and the performance is satisfactory under these scenes. This research proposes an adaptative pressure estimation and control architecture for integrated electro-hydraulic brake system which could eliminate pressure sensors in typical scenarios and ensure the comprehensive performance of pressure control.