Steering feedback has an important role in good vehicle guidance by the driver.
However, the design of the steering feedback usually happens late in the
development process with prototype vehicles, when significant changes to the
steering system are hardly possible. Hence, a steering system model is developed
for the early stages of vehicle development, which is able to predict the
transmission behavior of a steering system. Therefore, this article verifies
that the steering system can be modeled independently of the tires and axle for
relevant amplitudes of the steering feedback.
The developed steering system model is a two-mass model consisting of an
effective rack mass and a combined steering wheel and steering column inertia.
Both are connected via the spring stiffness of the steering column and a
steering gear ratio. Friction has a very dominant influence on the transmission
behavior of the steering system and is therefore modeled at the column and rack.
Furthermore, a driver and a steering controller model are used to examine
variations of configurations with a fixed and free steering wheel as well as an
active and inactive assist motor. The validation of the model with measurement
data shows good accuracy compared to a more complex state-of-the-art steering
model.
