ISBN 978-3-8439-3350-6

978-3-8439-3350-6, Reihe Ingenieurwissenschaften

Steve Armand Fankem Fankem
Steering Feel Generation in Steer-by-Wire Vehicles and Driving Simulators

270 Seiten, Dissertation Technische Universität Kaiserslautern (2016), Hardcover, A5

Zusammenfassung / Abstract

Unlike vehicles with conventional steering systems (CSSs), steer-by-wire (SbW) vehicles do not have a permanent mechanical linkage between the steering wheel and the vehicle wheels. Instead, the steering angle of the vehicle wheels is supplied by a wheel actuator, whereas a hand wheel actuator (HWA) provides the driver with the steering torque. This work addresses the steering feel generation (SFG) requiring a steering torque computation (STC) and a HWA. The STC computes the desired steering torque which must be felt by the driver, while the HWA realises the desired steering torque. The SFG is also needed in driving simulators (DSs) including a HWA. The objective of this work is to provide the driver with a realistic and highly customisable steering feel.

The first part of the work presents a new modular STC. The authenticity of the STC is shown transparently by comparing objective parameters of both the STC and a present-day, real electric power steering (EPS) system. Moreover, the selection of the tuning parameters and the modular structure of the STC are decisive for an efficient customisability of the steering feel, which can be personalised in a very intuitive manner as demonstrated.

The second part derives specifications for a HWA having a predefined architecture. The steering wheel motion perceived by the driver is influenced by following HWA properties: friction, damping as well as inertia of the mechanical drive, motor torque control, motor cogging torque, motor torque-speed characteristics, time delay and resolution of the position measurement. For these properties, specifications are derived for reproducing the steering feel of a pre-series car equipped with a series EPS system. Analyses are carried out with the help of a numerical simulation, a test bench, the pre-series car and a DS.

The last part deals with the function development for a SbW test vehicle used for the subjective evaluation of the STC. Following components are addressed: a steering torque feedback controller, a steering ratio computation, a rack position feedback controller and a rack force observer. For each component, the work provides performance requirements, highly accurate plant models supporting a model-based design. Moreover, the structure and the parameters of the components, which have been implemented in a rapid control prototyping setup, are presented. The function validation is made by means of experiment results.