Stability Analysis of Light Tractor and Semitrailer Combination When Trailer Wheels Are Steered

Several studies have been performed on improving the stability of articulated vehicles through trailer wheel steering, but the principle on which to base the control of such steering has not yet been clarified. The authors propose a method of semitrailer wheel steering control called "Vector Follower Control", and clarify the conditions which must be satisfied to achieve this control. Then, this method is evaluated through a series of simulations. The results indicate that this method is highly effective for improving both the directional stability and the tractor's track followability of the semitrailer. In order to confirm the results of the simulations, the authors conducted the lane change test and track followability test using a scale model (scale#1/8) with controllable wheels.