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Scientists at the Austrian Institute of Technology (AIT), formerly Austrian Research Center, focused on investigating electro mechanical brakes (EMB) for automobiles. Research showed that EMBs can address brake distribution with regenerative and friction braking ("blending") at hybrid and electric cars due to the ability of the EMBs to be actuated as required (and do not automatically produce brake force at pedal activation). The target was to develop an EMB with low actuation force and energy that is simple and reliable, rolls back to disengage when power is off and acts as a parking brake. Several solutions were considered (with and without self-amplification). A pivotal mechanism with very high transmission ratio using eccentricity emerged as a favorable solution. Vienna Engineering (VE) took over and assumed the research during 2010. VE revealed that non-linear behavior facilitated low actuation forces at high braking torque and can use a controlled amount of self-amplification.

With linear actuated brakes the actuation force (or torque) rises linearly from 0 to the full actuation force at full braking. This means that the actuation must be designed for the rare case of full-braking. The parts must be designed for this peak load (e.g. motor, gear) and the transmission ratio is determined by the full-braking actuation torque, which causes the highest transmission ratio and hence determines slow actuation dynamic. Ideally the actuation should make the fastest travel at low normal force and turn to slow movement and high force at the highest pad force. Mathematically the torque transmission ratio should optimally be an exact representation of the actuation characteristics (actuation torque over actuation movement), creating the highest torque-transmission ratio at highest force and the fastest movement at low pad force.

Since more than eight years Vienna Engineering (VE) is working on an electro-mechanical brake (EMB) actuated by eccentrics and a highly non-linear actuation mechanism. The principle allows full braking in approx. 70 milliseconds (including air gap) and only approx. 3 A RMS actuator current at 12 V for classical ABS with oscillations. This EMB reached an elaborated state. Versions for passenger cars, elevators, railway and commercial vehicles (CVs) were derived. Now, as the EMB is going to road tests, it is necessary to fulfill safety requirements closely. What are these safety requirements and how can they be fulfilled? The properties of the overall system, of the mechanics and electronics of the single brake are discussed in this paper. The overall brake system for EMBs needs a truly redundant power supply, a safe control bus and a safe brake pedal. The mechanics of a single brake can be required to release when power is off and it must not get mechanically stuck.