ARTICULATED VEHICLES: STABILITY AND ANALYSIS

The Liapunov stability theory is used to develop a relatively simple method of analyzing articulated vehicles by combining the vehicle dimensions and most other parameters into a single matrix. Analyses are performed to verify the analytical method and to demonstrate the ease of obtaining results without time-consuming computer simulation. Numerical results for three steady-state turns (gentle, moderate, and near maximum) are analyzed and verified with a 12-degree-of-freedom nonlinear time simulation. Turn radius, forward speed, steering angle, under/over steer, and trailing angle are compared; the differences in comparable values are less than 7%. A graph compares the trailing angle of a semitrailer in a loaded vs. unloaded condition. Stable regions of turning radius for steady-state turns are plotted as a function of forward speed for cornering coefficients of 0.5 and 0.2. The analytical stability condition for a trailer is reduced to the form for a linear oscillator. Analytical expressions for damping, natural frequency, and forward velocity for critical damping are developed and verified. An optimal trailer design is developed and analyzed; the results compare favorably to empirical trailer design and subjective evaluations. Appended are a description of the computerized nonlinear time simulation of vehicle dynamics and a listing of the computer code, and three sets of parameters which describe the study vehicles (two truck-semitrailers and a car-trailer).

• Corporate Authors:

  Notre Dame University

  Department of Aerospace and Mechanical Engineering
  Notre Dame, Indiana,   United States  46556
• Authors:
  • Dunbar, L K
• Publication Date: 1979

Media Info

• Features: References;
• Pagination: 96 p.

Subject/Index Terms

• TRT Terms: Analysis; Damping (Physics); Motor vehicles; Simulation; Speed; Stability (Mechanics); Steering; Tractor trailer combinations; Traffic speed; Trailers; Turning radius
• Uncontrolled Terms: Articulated vehicles
• Old TRIS Terms: Analytical method
• Subject Areas: Motor Carriers; Safety and Human Factors;

Filing Info

• Accession Number: 00371499
• Record Type: Publication
• Source Agency: National Highway Traffic Safety Administration
• Report/Paper Numbers: 8002607 Dissertatn, HS-030 600
• Files: HSL, USDOT
• Created Date: Mar 31 1983 12:00AM