Robotic airship trajectory tracking control using a backstepping methodology

This paper considers the design of a novel closed- loop trajectory tracking controller for an underactuated robotic airship having 6 degrees of freedom (DOF) and 3 controls, on forward, yaw and pitch motions using two side thrusters. A backstepping methodology is adopted as a design tool, since it is suitable for the cascaded nature of the vehicle dynamics. It also offers design flexibility and robustness against parametric uncertainties which are often encountered in aerodynamic modeling and air stream disturbances. Indeed, in our simulations we assume a 10% error in all dynamic parameters and yet the controller performs position, orientation, linear and angular velocities tracking successfully. We also impose an additional air stream disturbance and the controller corrects the vehicle's trajectory successfully too.