Vision based station keeping and docking for an aerial blimp

This paper describes a method for station keeping and docking of a lighter-than-air vehicle based on visual input. Due to the motion disturbances in the environment (currents), these tasks are important to keep the vehicle stabilized relative to an external reference frame. The main difficulties to achieve station keeping and docking are related to the nonholonomic constraints of the blimp moving in 3D, having a limited number of controllable degrees of freedom. The relative position of the vehicle with respect to a docking station is tracked using vision. A planar surface is chosen as a reference plane which allows visual tracking of an environmental region, based on planar projective transformations. An image-based control law is proposed together with a dynamic model for the vehicle. Experiments and results are described and discussed