Alfred Pruckner

Optimized Force Allocation -A General Approach to Control and to Investigate the Motion of Over-Actuated Vehicles

Abstract A general approach is introduced to allocate the forces acting on the center of gravity to the four wheels of a vehicle by using an inversion of vehicle dynamics and a non-linear optimization. This makes it possible to compare all useful configurations of actively and passively controlled influencing variables of vehicle dynamics (steering angles, brake/drive torques, wheel loads and camber angles), with and without actuator dynamics and to investigate the impact of actuator failures on vehicle dynamics.

Vehicle Dynamics per Software – Potentials of an Electric Single Wheel Drive

This paper outlines the advantages of drive train architectures which allow free distribution of wheel torques on the rear wheel axle, so-called torque vectoring, with respect to driving dynamics. Electric cars open up new possibilities with regard to vehicle architectures. Utilization of the new degrees of freedom might lead to architectures with rear wheel drive and high rear axle loads. For conventional cars without counteractive measures, e.g. mixed tires, this would inevitably lead to inappropriate driving behavior. It is shown that such boundaries are no longer valid for electric cars with high rear axle load in com-bination with rear wheel drive and torque vectoring.

Steer by Wire

Steer by Wire is an automotive system that electrically transmits a steering command from an operating element (steering wheel) by an ECU to an actuator executing the steering command at the driven wheels. These systems do not have any mechanical connection between steering wheel and driven wheels. To improve handling, the driving state delivers a haptic response to the driver by an active operating element.

Single wheel drives for wheel slip control

Ever-increasing electrification of the drive train offers new possibilities for the power train layouts as well as for vehicle dynamics control. For a single-wheel driven electric vehicle, one should utilize the advantages of the electric engines compared to conventional components. Within this contribution, an optimized arrangement regarding installation space of the drive train with single rear wheel drive was investigated. The electric motors were used for acceleration and deceleration, hence regenerative braking. Often, for brake situations with excessive wheel slip, electric engines are switched off and conventional components as the hydraulic wheel brakes are used to control the wheel speed. A control scheme for a rear-wheel driven electric vehicle with single wheel drives is presented, where only the rear engines and no friction brakes are used for all driving and braking torques. The effectiveness of the proposed control scheme has been proven in real vehicle tests for acceleration as well as for braking situations on low friction coefficient surface (snow).

The consequences of a closed rim design for the brakes of a high-efficiency vehicle

Highly efficient and especially electrified passenger vehicles labor to expand the CO2 reduction or driving range through many measures. One significant factor is the optimization of the aerodynamics. The wheel rim design of a vehicle has a noticeable impact on the drag coefficient (cd) of a passenger vehicle.