Adaptive backstepping trajectory tracking controller for a small-scaled helicopter

An adaptive backstepping controller is proposed to achieve the trajectory tracking for a small-scaled helicopter. The helicopter model is first decomposed into a cascade structure between the position and attitude loops with uncertain dynamics. The backstepping technique is introduced to exploit the controller based on the decomposed model and the upper bounds of the unmodeled dynamics are compensated with the hyperbolic tangent function. The controller introduces a dynamic auxiliary system to obviate the singularity during the derivation of the command attitude; and criteria of controller parameters are developed to guarantee the bounded tracking. In addition, command filters are employed to ease complex derivative calculations. The stability analysis proves that the proposed controller realizes the ultimately bounded tracking of the helicopter system. Simulations verify the performance of the proposed controller.