A Renewed Look at Centralized vs. Decentralized Actuation for Braking Systems

Abstract

De-centralized brake actuation – that is, brake systems that incorporate individual actuators at each wheel brake location to both provide the apply energy and the modulation of braking force – is not a new area of study. Typically realized in the form of electro-mechanical brake calipers or drum brakes, or as “single corner” hydraulic actuators, de-centralized actuation in braking systems has already been deployed in production on General Motor EV1 Electric Vehicle (1997) in the form of electric drum brakes and has been studied continually by the automotive industry since then. It is frequently confused with “brake by wire,” and indeed practical implementations of de-centralized actuation are a form of brake by wire technology. However, with millions of vehicles on the road already with “brake by wire” systems - the vast majority of which have centralized brake actuation – the future of “brake by wire” is arguable settled. The question of what is next for braking technology is centered more on study of de-centralized actuation. There is little debate, especially with modern electronics and computing power, on whether de-centralized brake actuation technology can work – the technical feasibility has been largely proven. The frontier of study of this technology is instead “does it make sense,” in other words do the benefits outweigh the initial investments and the risks for high volume production. This question cannot be answered from purely within the confines of the braking system itself, as it has far ranged implications on everything from manufacturing to interior layout, to energy efficiency, and it affects other major systems such as propulsion and electrical. The present work takes a holistic look at the implications, both positive and negative, for brake systems with de-centralized actuation, and make a case for why the time may finally be here for broader implementation.