Directional Response of Multi-Articulated Vehicles with Multiple Axles to Steering Input

Directional response and directional stability of vehicle combinations are main research topics in vehicle safety. This paper analyzes the steering sensitivity in lane-change maneuvers of multi-articulated vehicles with multiple axles using simplified mathematical models. It also calculates the frequency response, pole, and zero in the transfer functions of each variable for two types of tractor-double-trailer, a tractor-semitrailer and a truck-full-trailer having multiple axles. The following conclusions are drawn. (1) The steering sensitivity of multi-articulated vehicles with multiple axles in lane-change maneuvers is composed of steering sensitivity in steady-state turns and the parameters of lane-change maneuvers. (2) The effect of the number of trailer axles on the damping ratio of zero is larger than that of the other parameters for multiple axles. (3) A large steering angle is necessary to change running lanes for multi-articulated vehicles with multiple axles that have low steering sensitivity in lane-change maneuvers; therefore, the rise time is short. Moreover, if the vehicle combination has a low damping ratio of oscillatory modes, the settling time is long, and the overshoot and maximum deviation are large.