Abstract: In this paper, automatic control method is described for reversing motion of a tractor-trailer vehicle type mobile robot using optimal control theory. First, reference paths of tractor-trailer vehicle using feed-forward control were generated. Second, the kinematic model about a reference path was linearized. Third, a time-varying linear quadratic regulator (LQR) to path-tracking along the reference path was designed. The experiment was carried out on the asphalt parking area using desired reference paths and path-tracking controller. The experimental results demonstrate that the control method can be successfully used for autonomous tractor-trailer vehicle.