Lateral stability analysis of the tractor/full trailer combination vehicle
This paper presents a linear dynamics model of tractor/full trailer with six degrees of freedom, and a series of simulations are performed on obstacle avoidance manoeuvers in which the combination vehicle moves at a constant forward speed. It is found that the ratio of the peak lateral acceleration of the full trailer's center of gravity (CG) to that of the tractor is 2.3, meanwhile, the articulated angle of the trailer is larger than that of the dolly. This phenomena, defined as the ‘rearward amplification ratio’(RWA), leads vehicle to rollover easily. A larger wheelbase of trailer would be useful to improve the lateral stability of the combination vehicle but it is limited by width of the road. Acting a resistive torque on the turntable can be absolutely effective in improving the dynamics stability of the tractor/full trailer combination vehicle but if acted at hitch point it has little improvement.
A theoretical study of the yaw/roll motions of a multiple steering articulated vehicle
Abstract The objective of this paper is to present a theoretical analysis of the yaw/roll motion for an actively multi-axle steering articulated vehicle. The roll instability of articulated vehicles is one of the most serious problems for the vehicle's occupants. Therefore, it is necessary to develop both yaw and roll responses in a more comprehensive model to obtain an accurate result. In this study, a five-degree-of-freedom articulated vehicle with multiple steering mathematical model and the basic analytical results of the yaw/roll performance characteristics are presented. The use of an additional steering axle on the towed unit is shown to increase the directional stability, to reduce the roll angle and to minimize the lateral force during steady turning. Moreover, the effect of roll steer about the lateral force in steady state turning, lane change simulation and the influence of roll steer coefficients and location of the additional steer axle on critical speed are also discussed and illustrated. This study does not address the feasibility of implementing these systems or limiting of the driver using these systems.
An analysis of the directional response characteristics of double tankers (i. e. , two articulated tank-trailers in Tandem)
An analysis of the directional response characteristics of double tankers (i.e., two articulated tank-trailers in Tandem), undertaken as part of a larger study by the University of Michigan, Highway Safety Research Institute for the Michigan State Office of Highway Safety Planning, indicated that the double-trailer gasoline tanker configuration corresponding to that used in Michigan has a lightly damped mode of ''pup-trailer'' (i.e., the second trailer) oscillation that can be unstable at highway speeds when the rear compartment of the pup trailer is loaded and the other compartments of the pup trailer are empty. In addition, the lateral acceleration of the pup-trailer is much larger than that of the tractor of the vehicle train in obstacle-avoidance maneuvers at highway speeds. Modification of the vehicle train by rigidizing the connection to the pup trailer at the pintle hook greatly reduces this tendency. The analysis should provide valuable assistance in deciding among various approaches for developing vehicles of appropriate size and weight to deliver flammable liquids safely and economically.