The Effects of Tire Cornering Stiffness on Vehicle Linear Handling Performance

In this paper, the effects of tire cornering stiffness on vehicle frequency responses have been investigated. The high speed force and moment test data of four different groups of tires were collected. These tires had different constructions and wide ranges of cornering stiffness. The tire nonlinear lateral force and aligning moment were modeled using the Pacejka Magic Formula tire model.

Based on a full nonlinear vehicle model, vehicle linear handling performance was simulated with the above tires during pulse steer and step steer maneuvers. To evaluate the vehicle linear handling performance, the following vehicle dynamic parameters were selected: sideslip angle, yaw rate peak time, phase lags of yaw rate and lateral acceleration, yaw rate gain, yaw damping ratio and natural frequency. The sideslip angle and yaw rate peak time were obtained from the vehicle responses to a step steer input. The other parameters were derived by fitting the frequency response functions of yaw rate and lateral acceleration during a pulse maneuver to a two degrees of freedom linear “bicycle model.”

Two main conclusions have been drawn from this preliminary study: (1) higher tire cornering stiffness results in better vehicle linear handling performance; (2) different methods of evaluation give similar rating of the tires.