Multiple Steered Axles for Reducing the Rollover Risks of Heavy Articulated Trucks

This paper presents an analytical study of the performance improvements that can be obtained at both high and low speed using multiple steered axles on heavy articulated trucks. At high speed, rollover usually represents a worst case scenario. Therefore we have chosen to evaluate possible steering designs based on their ability to reduce lateral acceleration of the semitrailer center of gravity. This is in contrast to passenger cars where four-wheel steering has typically been evaluated based on measures that were thought to be related to driver acceptance. This paper also investigates the effects of steering rear tractor axles on the low-speed maneuverability of the vehicle.

Steering algorithms for the rear tractor tires were evaluated using frequency response and simulation of an obstacle avoidance maneuver. Results indicate that at high speeds considerable reductions in trailer lateral acceleration can be obtained during transient maneuvers. At low speeds, steering of the rear axles demonstrated improvements in maneuverability. More work is needed to determine if drivers are able to effectively make use of these improvements indicated by the open loop models, and to evaluate the practicality and cost of implementing these systems.