Integral Steering and drive module

Konzeption und Prototyp eines integralen Lenk- und Antriebsmoduls

The introduction of x-by-wire systems and the associated mechanical separation of actuators and control elements enables the development of very compact chassis modules with its own actuators. The corner module developed at ika and based on an invention of Prof. Eckstein combines drive, steering and brake in a particularly compact unit.

Previous corner modules from other manufacturers still consist of separate actuators for the drive and steering, which means that they not only weigh more but also require a relatively large amount of installation space. In order to optimize the performance, but also the size and weight of such systems, ika has developed a concept in which the actuators are no longer assigned exclusively to one task, but can be used for both the drive and the steering of the wheel.

The two actuators are arranged coaxially to the steering axis and connected to each other in the center of the wheel via a bevel gear. This means that the drive can be realized by the same torque of both actuators in opposite directions and the steering by the same torque in the same direction. In addition, both load cases can be superimposed. The maximum power of both actuators can therefore be divided as required between steering and driving. This allows the size of the actuators to be adapted to the maximum required system power. As the overall system itself is not stable, a suitable design of the complex control system was required, taking all boundary conditions into account.

After a promising simulation study, a 48 V powered prototype for L7e vehicles has been built and put into operation on a chassis test rig. The first results of this steering and drive module confirm the feasibility of the concept and show good  controllability of the overall system.