Image-based control of satellite-mounted robot manipulators

Robot manipulators have multiple uses and are especially useful when dealing with complex manipulation tasks in unstructured environments. This paper presents a direct image-based controller for performing the guidance of a free-floating robot manipulator. A camera is attached to the end-effector of the manipulator and the robot is attached to a base satellite. The proposed direct image-based control strategy computes the torque to be applied to the joints, and takes into account the system's kinematics and dynamics model. The operation is such that the base is completely free and floating in space with no attitude control, and thus freely reacting to the movements of the robot manipulator attached to it. The main objective is to track a desired trajectory in the image space with respect to an observed object in space. The proposed control strategy optimizes the motor commands with respect to a specified metric. The controller is applied to direct visual control of a four-degree-of-freedom robot manipulator.