Effect of handling characteristics on minimum time cornering with torque vectoring

ABSTRACT

In this paper, the effect of both passive and actively-modified vehicle handling characteristics on minimum time manoeuvring for vehicles with 4-wheel torque vectoring (TV) capability is studied. First, a baseline optimal TV strategy is sought, independent of any causal control law. An optimal control problem (OCP) is initially formulated considering 4 independent wheel torque inputs, together with the steering angle rate, as the control variables. Using this formulation, the performance benefit using TV against an electric drive train with a fixed torque distribution, is demonstrated. The sensitivity of TV-controlled manoeuvre time to the passive understeer gradient of the vehicle is then studied. A second formulation of the OCP is introduced where a closed-loop TV controller is incorporated into the system dynamics of the OCP. This formulation allows the effect of actively modifying a vehicle's handling characteristic via TV on its minimum time cornering performance of the vehicle to be assessed. In particular, the effect of the target understeer gradient as the key tuning parameter of the literature-standard steady-state linear single-track model yaw rate reference is analysed.

KEYWORDS:

• Torque vectoring
• vehicle handling
• electric vehicles
• optimal control
• yaw rate reference
• minimum time

Acknowledgements

A.M.D.G.

The authors thank Efstathios Siampis for support with optimal control.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

E. N. Smith http://orcid.org/0000-0003-3954-5684

Notes

1. Aristotle. Physics, 195a.

Additional information

Funding

This work was supported by the Engineering and Physical Sciences Research Council Industrial Cooperative Awards in Science & Technology studentship with sponsor Jaguar Land Rover under Grant [EP/K504324/1].