Objective ride quality evaluation of a multi-link torsion axle for battery electric vehicles

In this work, the ride quality of the novel multi-link torsion axle (MLTA) was experimentally evaluated. The kinematic topology of this suspension concept is designed to maximise the coherent package space in the underbody of small- to medium-sized battery electric vehicles (BEVs) to offer an increased installation space for the traction battery. Because of this suspension design, several compromises concerning longitudinal and vertical behaviour dynamics must be made. This work transfers the relevant kinematic and compliance characteristics on the suspension level to the full-vehicle ride comfort. Therefore, a full vehicle equipped with the novel MLTA as well as a conventional twist-beam axle (TBA) was tested on different uneven roads and single obstacles. As a result, the level of discomfort on the driver and on the chassis was assessed according to the international standards and best practices established in the literature. It was found that in its current state, the vehicle variant with MLTA has a higher level of discomfort in the vertical direction than the variant with TBA. However, the difference is in a tuneable range. Also, it was found that the MTLA offers a significant improvement for longitudinal chassis acceleration when driving over cleat-type obstacles.