The Wheel-Individually Steerable Front Axle of the Research Vehicle SpeedE

Summary The Institute for Automotive Engineering at RWTH Aachen University (ika), is currently developing, constructing, and implementing the research vehicle SpeedE as an open research and innovation platform for research and industry. The research focus of the SpeedE concept, amongst other things, is the innovative front suspension. Not only is the front axle’s steer-by-wire system able to steer each wheel individually, but it is also able to achieve steering angles of up to 90°. The central core of the steering system is made up of two electric motors in combination with harmonic drive reduction gears integrated in the upper control arms of a double wishbone suspension, which is accompanied by a replacement of the outer ball joints of the upper control arm by cardan joints and an elimination of the tie rods. The focus of this article is to present the topology of the front axle and the development methodology used during the design of the front axle. Based on example challenges that had to be overcome by the requirements inherent in the system, the associated solutions implemented for the selection of the position of the steering axle, and the chassis attachment points as well as the orientation of the cardan joint are discussed in this paper.