Simulation in the Development of the Electronic Wedge Brake 2006-01-0298

The Electronic Wedge Brake (EWB) is a new electromechanical braking system with a high self-reinforcement factor. This results in low power consumption, providing the perfect platform for X-by-Wire technologies. However, the unusual energetic relationships in the mechanics require a different approach to brake design, since the actuator itself can be unstable without proper control software. This fact and several other engineering challenges make simulation indispensable in the design process, from individual components, through larger subsystems, and up to the whole brake system including the vehicle and human driver. The simulation results are not only an important part of the development process, but are also useful tools for explaining the brake to third parties.

An earlier SAE Paper [1] discussed modeling of the brake itself for the purposes of brake control law design. This paper focuses on higher level models, suitable for the development of vehicle level functions including ABS, ESP, traction control, brake force distribution, and brake behavior at low speeds. The various degrees of hardware-in-the-loop testing used in the development process are described. Vehicle simulation results are presented to demonstrate the use of these models in developing such systems. In particular, it is shown that there are significant benefits to be gained from an engineering and demonstration software tool with advanced 3D visualization. This provides the user with both the capability for analytical design and a subjective feel for the impact of the design on vehicle dynamics. In conclusion, the proper simulation tools can significantly improve the development process, making it possible to parallelize work packages, reduce development testing, and cut costs. With novel products such as the wedge brake, they can also have a role to play in explaining the system and improving market acceptance.