Design of an experimental platform for an x-by-wire car with four-wheel steering

Abstract — In times of increasing fuel price and environmen-tal consciousness coming to the fore, automotive industry is forced to review its existing concepts of building cars based on combustion engines. In addition to other technologies like hydrogen or fuel cell technologies, electric cars with highly effi-cient battery power supply play a fundamental role. Especially electric cars with wheel hub drive offer great flexibility of car design and approve completely new mobility concepts. Our contribution to this trend is the setup of a new electric X-by-wire car, characterized by four synchronously controlled wheel drives and four steering drives, which is meant to be a development environment for both mechanics respectively electronics and software. As this prototypic construction allows a full vertical rotation of each wheel, new movement abilities result with demanding steering tasks, as far as control itself and safeguarding against failure is concerned. For instance, the car cannot just direct into a curve, the car can also drive sideways or rotate around arbitrary pivot points. This paper presents a prototypic implementation of such an electric car, ready to serve as a basement for innovative mobility concepts for the future. Index Terms — Electric vehicle, in-wheel drive, X-by-wire, prototype, four-wheel steering