Methodologic Assessment of Brake-by-Wire System Modelling with Regard to Accuracy, Model Complexity and Optimization Efforts 2023-01-0666

Brake-by-wire systems are an innovative and important component of modern high-performance and also electrified vehicles. Due to their decoupled architecture, they enable driver-independent vehicle dynamics control (e.g., brake torque blending) and easy integration of assistance functionalities (e.g. Emergency Brake Assist (EBA)). On the other hand, the development of these functions can cause high costs and development effort, and testing can be critical in case of improper gain tuning. Therefore, already in the concept phase, a large part of the testing is shifted to virtual environments and simulations that allow safe and reproducible experiments without damage. Therefore, suitable and reliable models are needed to represent reality as accurately as possible.

This paper deals with the modelling of a purely electrohydraulic brake-by-wire system and a hybrid system with electrohydraulic brakes on the front axle and electromechanical brakes on the rear axle. For comparison, both an experimental approach based on a second-order transfer function and an analytical model are used. These approaches are then evaluated in terms of their accuracy and reliability using real measurements in different dynamic test setups. Finally, it is shown how accurate the approaches are and what advantages can be achieved by using the different methods for system modelling.