Comparative study of stabilization controls of a forklift vehicle

This paper presents the control designs for an autonomous forklift vehicle that drive the vehicle from an initial configuration to a final one. Three stabilization controls, which are chained-form time-varying control, sigma-transformed discontinuous control, and navigation-variables-based discontinuous control, for a forklift vehicle are compared by simulations. The sigma-transformed and navigation-variables-based discontinuous controls provide fast convergence motions from an initial to a final configuration, while the time-varying-based control provides oscillatory motion and slow convergence. The sigma-transformed discontinuous control has a set of discontinuous points in which, from a practical point of view, the control signals can blow up if a vehicle enters the set. The navigation-variables-based control, which also has a discontinuous point at the final configuration, does not produce blown up control signals since its boundedness nature. Discussion on the implementation of control algorithm is elucidated for the three stabilization controls for the forklift vehicle.