MIT Scientists Develop Cable Manipulation System with Tactile-Reactive Gripper

We, humans, can grasp a cable, know its pose, and follow it end to end with ease, like straightening as USB cable to connect a smartphone to PC for data transfers. For robots though, that’s a monumental undertaking, or at least it used to be as researchers from MIT’s CSAIL have created a robotic gripper that can determine cable pose and follow it to its end.

The cable manipulation system with tactile-reactive gripper’s secret that allows it to pose and handle cable lies in its gripping mechanism, which is outfitted with GelSight vision-based tactile sensors. The sensor is designed using a low-tech solution of sorts, which consists of a block of transparent rubber that’s coated with metallic paint. When the paint-coated rubber is pressed against an object, it conforms to its shape and makes it reflective. On the opposite side of the paint-coated face are a trio of colored lights and a single camera that computer vision algorithms use to pick out minute details of the object the sensor is in contact with.

The cable manipulation system was developed using four modules, including a tactile-reflective gripper equipped with the GelSight sensors, which operates at a 60MHz grip bandwidth control. The second module features tactile perception that estimates in real-time the pose of the cable, the friction force pulling from the gripper. The third offers the cable grip controller, which is operated using a PD controller and a leaky integrator, which modulates the friction force on the cable, as well as providing grip forces that result in imprints that can be used for perception. The fourth module features a cable pose controller that lets the robotic gripper manipulate the cable configuration via an LQR controller.

The scientists state they would like to research other models and controllers, including those that utilize reinforcement learning for increased accuracy and cable-gripper dynamics.