Developing Mechatronic Steering Systems

Task

The steering system and its characteristics decisively affect a vehicle's driving behavior and feeling. Haptic feedback plays a vital role here, as it gives the driver vital information about the road and the vehicle. It is only when the overall steering system is integrated into the vehicle that developers can actually experience it. As this subjective impression is very important and the integration process is expensive, another approach is needed.

Challenge

The test system needs to provide haptic feedback and offer a close-to-reality environment simulation for a realistic steering feeling and driving behavior. Its purpose is to give an initial impression at an early stage of product development. The simulation model has to take extra features into account, such as automatic parking and lane-keeping assistants for enhancing comfort and active safety.

Solution

dSPACE combines a HIL steering test bench and a static driving simulator that enables pre-calibration on a virtual experimental vehicle. The test apparatus consists of the real steering system with its actuators, and the driving simulator with a load machine for the steering wheel and accelerator and brake pedals. Both are coupled to the dSPACE Automotive Simulation Models (ASMs) running on a quad-core DS1006 Processor Board. The ASMs are open Simulink models for the real-time simulation of passenger cars, trucks and trailers that simulate the vehicle's vertical, longitudinal and lateral dynamics as a multibody system with 24 degrees of freedom.

Visualization is done with dSPACE MotionDesk using small LCD monitors representing the outside and inside rear-view mirrors. The sensation of driving is further intensified by road and engine noises.

The system is used not only to investigate and adjust steering systems, but also to run driver assistance systems such as lane departure warning systems.