Research On Electrical Braking Technology Of Autonomous Vehicles

The autonomous driving technology of vehicle is being carried out in real world both in civilian fields and military fields, however, the application of unmanned vehicle still needs proof and practice. Autonomous vehicles will be in the stage of co-drive for a long time, that is, driver-control and autonomous system assisting or autonomous system control and driver assisting. Braking system is the most important system of vehicle security. Thus, new requirements for braking system are raised. Aiming to complete the Electrical Braking function for a co-drive system, this dissertation conducts research on some key technologies of Electrical Braking system through functional analysis, theoretical analysis, system design and real world experiments.The dynamics of vehicle platform and the kinetics of hydraulic brake booster and master cylinder during braking are analyzed, given the vehicle dynamics parameters. D-range sliding pedal brake experiments are conducted, and the braking process parameters are obtained.A double circuit electrical hydraulic braking(EHB) system was implemented, in consideration of the structures and features of hydraulic power braking of the four-wheel drive off-road vehicle(DFM). The system can implement electrical brake at the autonomous mode and pedal brake at the manual mode. Meanwhile, the two modes can be switched seamlessly, and the manual mode has a higher priority than the autonomous mode. Components and installation parts for vehicle transformation are selected, the dynamic analysis and feasible verification of the Electrical Hydraulic Braking(EHB) system’s power plant is conducted, and the mechanical structure and oil system transformation of vehicle platform is completed. Interface resources of the controller is listed, and circuit is transformed aimed at the requirements. Meanwhile, the software system is programmed, including pedal brake and electrical brake switching, brake pressure control, remote brake control, fault diagnosis and protection, throttle control, throttle and brake interlock control, serial communication and CAN communication. What’s more, a data acquisition and debugging software based on VB language is devised.Static and real world experiments are carried out to obtain the biasing and response characteristics of the system. On this basis, electrical braking experiments were conducted.Experiment results showed that the EHB system can meet the requirements of autonomous vehicle. In the end, a feedforward and feedback speed control method is proposed in consideration of the calibration data of this dissertation.