Hybrid vision/position servo control of a robotic manipulator

The authors address a number of issues associated with visual servo control of robotic manipulators. They derive a set of projection equations that are used in the derivation of the Jacobian matrix for resolved-rate visual servo control. A calibration procedure that determines those parameters that appear in the projection equations is presented. Given the projection equations and calibration procedure, a set of equations is derived that can be used to initially position the manipulator at a specified perpendicular distance from the camera such that the tool center of the end effector projects onto a specified pixel on the image plane. A Jacobian matrix that is used to effect hybrid control of the manipulator is derived. Specifically, the two degrees of freedom parallel to the image plane of the camera are controlled using visual feedback, and the remaining degree of freedom is controlled using position feedback provided by the robot joint encoders