Steering Characteristics of AWS(All Wheel Steering) System using Virtual Rigid Axles

초록

The bimodal tram is an articulated vehicle with rubber tires. Because the bimodal tram has an extended wheel base and articulated chassis, an AWS (All-Wheel-Steering) system is applied to it to satisfy the required steering performance. There are many methods to control the rear wheels such as front wheel steering angle proportion, steering force feedback, yaw rate feedback and zero side slip angle. The AWS control method using virtual rigid axles is applied to the bimodal tram. The virtual rigid axle is defined as the virtual axle which is not steered at the point where turn center and vehicle body meet perpendicularly. A vehicle with an FWS(front wheel steering) system has a fixed rear axle, whose extended line meets the turn center. In case of an AWS vehicle, the virtual rigid axle is in charge of its role and controls the angles of the rear wheels. In this paper, the steering characteristics of AWS system using virtual rigid axles were analyzed. The simulation and driving test were also performed to evaluate the stability and turning performance of AWS system.