Path following algorithm and experiments for an incomplete symmetry unmanned amphibious platform

摘要

The path following problem of incomplete symmetry unmanned amphibious platform was addressed. Considering the environmental disturbances the mathematical model of unmanned amphibious platform was established, and its control inputs were transformed from force and torque to water gate openings and pedal position. The path following error system, which was obtained after the former model being described in Serret-Frenet coordinate, was separated into two cascade subsystems, i.e., the position following subsystem and the orientation & surge velocity following subsystem. Then the equivalence between the second subsystem and the path following error system was proved on the basis of cascade theory. The globally asymptotically stable controller of orientation & surge velocity following subsystem was established based on backstepping adaptive sliding mode control method. The mathematic simulations and experimental tests were carried out, which illustrated that it was available for the incomplete symmetry unmanned amphibious platform to track the straight-line and circle path robustness under disturbances.