Dynamic-deflection tire modeling for low-speed vehicle lateral dynamics

Vehicle lateral dynamics depends heavily on the tire characteristics. Accordingly, a number of tire models were developed to capture the tire behaviors. Among them, the empirical tire models, generally obtained through lab tests, are commonly used in vehicle dynamics and control analyses. However, the empirical models often do not reflect the actual dynamic interactions between tire and vehicle under real operational environments, especially at low vehicle speeds. This paper proposes a dynamic-deflection tire model, which can be incorporated with any conventional vehicle model to accurately predict the resonant mode in the vehicle yaw motion as well as steering lag behavior at low speeds. A snowblower was tested as an example and the data gathered verified the predictions from the improved vehicle lateral model. The simulation results show that these often-ignored characteristics can significantly impact the steering control designs for vehicle lane-keeping maneuvers at low speeds.