Path-Following Control for an Under-actuated Airship Based on Serret-Frenet Frame

This paper addresses a new planar path-following control design for an under-actuated airship. First, the path-following error dynamics expressed in the Serret-Frenet frame is established and the desired attitude is prescribed carefully for the inner-loop design. Then, the attitude stabilization controller is proposed to achieve the desired attitude commands, and therefore the path-following errors are eliminated. To avoid the involved zero dynamics analysis for the sway velocity, a new velocity tracking control strategy is proposed by aligning the resultant velocity of the surge and the sway velocity tangent to the path. Finally, the simulation results of an under-actuated airship are shown to verify the effectiveness of the proposed method.