SIMULATION STUDY OF MOTORCYCLE STABILITY AT HIGH SPEED

A comprehensive digital computer simulation of a two-wheel vehicle and rider has been developed and is being used to study motorcycle stability and handling. The simulation is based on a nonlinear mathematical model with eight degrees of freedom, including steer and rider lean. Tire side force and aligning torque as nonlinear functions of slip angle, camber angle and vertical load, aerodynamic drag, pitching moment and steering torque, steering damping, and gyroscopic effects of the engine and wheels are modeled as well as fork rake angle, steering trial, and the basic physical characteristicsof the motorcycle frame, steering assembly, and rider. These parameters are input data to the computer simulation which produces output in the form of time histories of the motion variables of the vehicle. The two-wheel vehicle simulation has been validated by comparison with experimental tests using an instrumented vehicle. A combined analytical and experimental research program has been conducted as a coordinated effort by Calspan Corporation and the Harley-Davidson Motor Company, Inc. to study the weave instability phenomenon which can motorcycles at high speeds. "Speedman's wobble", as it has been called, is characterized by coupled steer-roll-yaw motions of the vehicle and has long been recognized by theoretical dynamicists. The influence of several motorcycle characteristics on weave instability have been evaluated in the context of total system performance by simulating the disturbance-response behavior at high speed. /Author/

• Supplemental Notes:
  • Sponsored by the National Motor Vehicle Safety Advisory Council and U.S. DOT. Presented at the International Congress on Automotive Safety (2nd), 16-18 July 1973.
• Corporate Authors:

  Calspan Corporation

  4455 Genesee Street
  Buffalo, NY  United States  14225
• Authors:
  • Roland, R D
• Publication Date: 1973-7

Media Info

• Features: Figures; References; Tables;

Subject/Index Terms

• TRT Terms: Aerodynamics; Handling characteristics; High speed ground transportation; High speed vehicles; Motorcycles; Simulation; Speed; Stability (Mechanics); Steering
• Uncontrolled Terms: Handling
• Subject Areas: Highways; Railroads; Safety and Human Factors;

Filing Info

• Accession Number: 00098858
• Record Type: Publication
• Source Agency: National Safety Council Safety Research Info Serv
• Report/Paper Numbers: No. 73020 Conf Paper
• Files: TRIS
• Created Date: Nov 5 1975 12:00AM