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Siemens VDO is currently developing a brake -by-wire solution called the Electronic Wedge Brake (EWB). Earlier prototypes used a two -motor concept inside the brake actuator to drive the wedge. In this paper, a new prototype generation is presented where only one motor is needed. This is more efficient in terms of cost, and actuator weight, and also reduces the complexity of the control strategy. A state -space model is derived for the new actuator and two controller structures are explained. Simulations and experimental results from a roller test bench are shown.

Future driver assistance systems will not only monitor the current traffic situation, but actively assist the driver in emergencies. Autonomous intervention in vehicle dynamics will increasingly help keep the vehicle under control, even in difficult operating situations. A rapid and intelligent braking system is one of the foundations for advancing the next generation of driver assistance systems. Siemens VDO sees its electronic wedge brake (EWB) brake-by-wire technology as the answer to future vehicle chassis safety, weight, reliability, and space requirements. In early 2005, Siemens VDO Automotive AG acquired the innovative company eStop to enter the automotive brake market with the EWB. The EWB is a self-reinforcing electromechanical wedge brake, which operates around the point of maximum self-reinforcement, in order to minimize actuation forces to levels that can be supported by 12V vehicle electrical systems.

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.

The eBrake is a novel self-reinforcing electromechanical wedge brake, which operates around the point of maximum self-reinforcement in order to minimise actuation forces. Beyond this point, the system would be unstable without an electronic controller. It is therefore important to demonstrate that this controller is robust to the range of parameter variations likely to be encountered in practice. The first stage of this process can be conducted on a dynamometer under laboratory conditions, to ensure that problems are addressed before proceeding to vehicle tests. This paper reports testing of the prototype brake on a such a dynamometer. The prototype brake itself is first briefly described, including the main instrumentation used during the tests. This followed by a short section detailing the capabilities of the dynamometer.

The eBrake® is a novel self-reinforcing electromechanical wedge brake[1]. Self reinforcement reduces the actuation forces, resulting in a more efficient and smaller brake, but demands more precise control than a conventional braking system. As a result, mathematical modelling and control law development plays a significant role in the development process. This paper describes the mathematical model of the brake and its validation against the prototype hardware. It is shown that there is a good correspondence between theory and practice, demonstrating both the validity of the model and its potential as a tool in future developments. Both the model and test results illustrate that the potential advantages of this design are realisable in practice.