Lateral dynamics emulation via a four-wheel steering vehicle

Abstract

In this paper, we examine the lateral dynamics emulation capabilities of an automotive vehicle equipped with four-wheel steering. We first demonstrate that the lateral dynamics of a wide range of vehicles can be emulated, either with little or with no modification on the test vehicle. Then we discuss a sliding mode controller for active front and rear wheel steering, in order to track some given yaw rate and side-slip angle. Analytically, it is shown that the proposed controller is robust to plant parameter variations by±10%, and is invariant to unmeasurable wind disturbance. The performance of the sliding mode controller is evaluated via computer simulations to verify its robustness to vehicle parameter variations and delay in the loop, and its insensitivity to wind disturbance. Finally, the emulation of a bus, a van, and two commercially available passenger vehicles is demonstrated in an advanced nonlinear simulator.

Keywords:

• vehicle emulation
• lateral dynamics control
• four-wheel steering

Acknowledgements

This work was partially funded by the CEmACS Project 004175. The European Union is not responsible for any data appearing in this publication. The authors would like to thank Robert Shorten of the Hamilton Institute for valuable discussions, and the anonymous reviewers whose comments have contributed to the clarity of the presentation.

Notes

1. Nomenclature for parameters in Table 1.

2. For notational convenience, we will denote () by (A, B, E) in the remainder of the paper.

3. The procedure in the sequel can be extended to cover a wider range of parameter variations if needed.

4. This was the amount of delay that was presumed initially in the controller loop on the test vehicle. Later, it was confirmed that the delay in real implementation was negligible.