Smooth Transition from Motion to Force Control in Robotic Manipulation Using Vision

Sensor-based robotic manipulation is becoming more and more popular as it promises increases in productivity, flexibility, and robustness of manipulation. Combining visual and force sensing is currently one of the most promising approaches for sensor-based manipulation, as vision and force are two complementary sensing modalities. One approach for multi-sensor use is the traded control where the robot is at each time controlled using one sensing modality, and the controllers are switched based on sensory input. One of the major problems with such systems is the transition between visual and force controllers. In this paper, we present a smooth transition method from motion to force control. The velocity of the end-effector is controlled by estimating the distance to the target by vision and determining an optimal velocity profile giving rapid approach and minimal force overshoot. Experiments show that the proposed control scheme is superior to earlier approaches