Current Research at German Aerospace Center (DLR) on Vehicle Dynamics and Control using Modelica and FMI Technology for Development, Control Design and Testing

Abstract

This talk is separated in three parts as follows. First the ROboMObil – the German Aerospace Center’s (DLR) robotic x-by-wire research platform – system architecture is sketched and details on the central control system inspired by robotics are given. Moreover different controller modules in this hierarchic control scheme, such as the adaptive path planning or the semi-active damper control are outlined and experimental results are shown. In the second part of the talk details on the implementation of Modelica based FMIs on the DLR robotic motion simulator (RMS) are provided. In connection to the ROboMObil controller design it is shown how DLR’s Modelica vehicle dynamics models are used for the controller synthesis as well as in their assessment by means of the FMI/Modelica based static and dynamic hardware in-the-loop (HIL) configuration. In the last part an excerpt of an industrial project in cooperation with Toyota is briefly presented. Applying light-weight construction methods to the design of future vehicles results in weight reduction of both the vehicle body and the chassis. However, the potential for percental reduction of the sprung mass is larger compared to that of the unsprung mass. This has unfavorable consequences on the compromise between ride comfort and road holding. To counteract these effects and recover the state-of-the-art comfort and road holding performance of nowadays`s passenger vehicles, a possible mechanical design solution introducing the wheel carrier splitted into two parts has been investigated. A comprehensive investigation on the influence of such suspension design on the ride comfort and tire/road contact has been done utilizing a Modelica model. Simulation results show that the ride comfort can be improved significantly while there is a negligible influence on the vehicle dynamics.