Nonlinear pose tracking controller for bar tethered to two aerial vehicles with bounded linear and angular accelerations

摘要

We consider a system composed of a bar tethered to two aerial vehicles, and develop a controller for pose tracking of the bar, i.e., a controller for position and attitude tracking. Our first control step is to provide an input and a state transformations which convert the system vector field into one that highlights the cascaded structure of the problem. We then design a controller for the transformed system by exploring that cascaded structure. There are three main contributions: i) we provide bounds on the linear and angular acceleration of the bar that guarantee well-posedness of the controller, and such bounds can be used when selecting the gains and saturations of bounded controllers for both three dimensional and unit vector double integrators; ii) the proposed control law includes a degree of freedom which can be used to regulate the relative position between the aerial vehicles; and iii) the proposed control law for the throttle guarantees that the cascaded structure of the problem is preserved. Simulations are presented which validate the proposed algorithm.