An Economical Multilevel Backup Strategy for Electro-Hydraulic Braking System by Integrating Driving and Electronic Parking Brake Systems

The braking system stands as a vital component within a vehicle; its malfunction has the potential to precipitate catastrophic or severe accidents. There are two primary backup strategies: one involves hardware redundancy, and the other is the optimization of software strategies in conjunction with other systems. Redundancy among various actuators of the second strategy not only maximizes the vehicle's inherent capabilities but also results in cost savings. In this article, a multilevel backup strategy that integrates electro-hydraulic braking, driving systems, and electronic parking brake systems is explored. Utilizing a self-developed braking safety control system, a proposal is made for the electronic parking brake to participate in service braking. Additionally, two functional modules, pre-clamping and deceleration following, have been meticulously designed to tackle the challenges of response delay and insufficient control precision that are commonly associated with electronic parking brakes. The effectiveness of the backup strategy was confirmed through real-vehicle testing. The results demonstrate that this multilevel backup strategy can provide a deceleration capacity of at least 4.88 m/s2 in the worst-case scenario, which is twice the requirement set by national standards.