Driving dynamics control

The integrated chassis control of over-actuated X-by-wire architectures (such as the ROboMObil), in which the steering angle, drive and braking torque of each wheel can be individually specified, is a key research topic at the institute. These architectures offer unique possibilities such as increased manoeuvrability, improved stability and optimised energy efficiency. However, they pose challenges for vehicle dynamics control, such as the interaction of the many actuators to fulfil a motion specification. The motion execution layer in the scalable architecture for controlling vehicle dynamics is being developed with the aim of overcoming these challenges. The main objective of its core function, the vehicle dynamics controller (VDC), is to distribute the control effort across the actuators (manipulated variable distribution) so that the kinematic motion requirement generated by the vehicle application layer is precisely realised. Other requirements such as driving stability and optimised energy efficiency are also met. The VDC uses a quasi-decoupled representation of the vehicle's lateral dynamics in order to be able to control the vehicle's slip angle and yaw rate independently. The transient behaviour was further improved with the help of an inverse vehicle model. In addition, real-time capable, optimisation-based approaches were investigated in which the control variable distribution aims to minimise energy losses and tyre slip. The designed VDC was implemented in the central control unit of the ROboMObil and thoroughly validated in several test campaigns on different road surfaces on vehicle test tracks throughout Germany under critical and non-critical driving manoeuvres. MPC was also investigated in combination with inverse model-based manipulated variable distribution in a separate study. Models with different levels of detail for vehicle dynamics and components form the basis for all activities in the automotive sector. Modelica libraries in the areas of vehicle dynamics, driver models, powertrain and vehicle control have been the focus of development in recent decades. Current contributions include vertical dynamics and detailed stabiliser models, which can be used to simulate driving manoeuvres as well as noise, vibration and load scenarios.