Development of a teleoperation system with a new workspace spanning technique

The task of accurate teleoperation of a large workspace industrial manipulator using a small haptic device having a physically limited workspace still a challenge. This task should be handled carefully without disturbing the user perception of continuously teleoperating the manipulator movement in a natural and precise way. This paper presents the development of a master/slave teleoperation system based on a new workspace spanning technique that integrate position control and a modified rate control methods to solve the problem of workspace mapping of two kinematically dissimilar robots. The proposed technique referred to as Positioning with Modified Rate Control is simple yet efficient and overcomes most of the drawbacks of other techniques. It depends on switching between rate control with constant speed for coarse motion and position control for accurate movements. The developed system consists of a phantom premium haptic device as a master and RV-2AJ Mitsubishi robot arm as a slave. Experimental results demonstrate that the operator can easily navigate through the whole workspace of an industrial robot using a small haptic device while achieving accurate positioning. The developed system proved experimentally to have good tracing characteristics in the fine manipulation mode. Besides, a 6 DOF force/torque sensor is attached to the end effector and tested for contact with different stiffness materials.