Implications for both driver and vehicle of attempting to follow a superelevated road curve are described, and a Prescribed Trajectory Vehicle Model is devised which permits the computation of steer angle and vehicle motions in response to a given horizontal and vertical road alignment. The modeled vehicle has pitch and bounce degrees of freedom, in addition to the usual lateral degrees of freedom in sideslip, yaw, and roll. Equations of motion are derived by Lagrangian methods, with generalized coordinates defining vehicle orientation relative to a moving constraint (road surface). Equations are linearized in generalized coordinates, but there are no restrictions on the roadway input's form. Effects of changing various road geometric parameters are explored in numerical experiments, with reference to the compatibility between the roadway input visible to the driver and the control response required of the driver, and in terms of the transient vehicle motions and body forces experienced by the driver. Possible improvements to the vehicle model, at the expense of a great increase in complexity, include representation of effects normal loads have on tire characteristics, inclusion of steering system dynamics so that steering wheel torque required from the driver can be investigated, improvement in tire modeling to include normal and lateral flexibility, and provision for varying vehicle forward speed. Equations of motion and an equation to calculate steer angle are appended.

  • Supplemental Notes:
    • Also published in HS-026 982U, "The Dynamics of Vehicles on Roads and on Railway Tracks. Proceedings of International Union of Theoretical and Applied Mechanics Symposium, Delft, Netherlands, 1975 August 18-22," 1976 p 60-85. Sponsored by Australian Road Research Board.
  • Corporate Authors:

    International Union of Theoretical and Applied Mechanics

    Chalmers University of Technology, Sweden
    S-412 96 Gothenburg,   Sweden 
  • Authors:
    • Good, M C
  • Publication Date: 1976

Media Info

  • Features: References;
  • Pagination: 26 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00394096
  • Record Type: Publication
  • Source Agency: National Highway Traffic Safety Administration
  • Report/Paper Numbers: HS-026 985U
  • Files: HSL, USDOT
  • Created Date: May 31 1985 12:00AM