High-Speed Scooping: An Implementation through Stiffness Control and Direct-Drive Actuation

This study presents the technique of robotic high-speed scooping: rapidly picking an object lying on a support surface by making contact with the object's open top face and the bottom face that is hidden in contact with the support surface. Essential to high-speed scooping is thus to make suitable dynamic, impactful interaction happen among the robot, object, and environment under errors and uncertainties. We propose a solution to this challenge based on stiffness control, an approach for indirect force control using the robot that is arranged to behave like a desired mechanical system. An implementation of the solution is then presented using a custom-built two-fingered direct-drive gripper. Our experiments verify that high-speed scooping operation is achievable, with the duration of dynamic interaction less than 0.3 s, and effective to various scooping situations featuring objects durable and fragile.