Variable structure PID controller for cooperative eye-in-hand/eye-to-hand visual servoing

This paper presents an experiment on the use of a cooperative camera system for robotic tracking of an object moving on a plane. The image of the object is acquired from two cameras, the first one (camera in hand) mounted on the end-effector of a 6 DOF robot arm (Puma 260) and the second one fixed in a certain location (fixed camera). The images are processed by a frame grabber on a standard PC, and the controller has a variable structure, which is capable to change from a PID to PD and vice versa according to the dynamic of the target.