Autonomous rendezvous using artificial potential function guidance

A novel methodology has been developed for the guidance and control of a maneuvering chase vehicle undergoing terminal rendezvous in the presence of path constraints and multiple obstructions. The method hinges on defining a suitable scalar function which represents an artificial potential field describing the locality of the target vehicle. Using a set of bounded impulses the chase vehicle is guided by the local topology of this potential function. Obstructions and path constraints are introduced by superimposing regions of high potential around these regions. Exact, analytical expressions are then obtained for the required control impulse magnitude, direction and switching times using the second method of Lyapunov. These control impulses ensure that the potential function monotonically decreases so that convergence of the chaser to the target is ensured analytically, without violating the path constraints. Since the components of the potential and control impulses may be represented analytically, the method appears suitable for autonomous, real-time control of complex maneuvers with a minimum of onboard computational power.