This paper proposes an algorithm for the scrollic (synchronously closing with rolling constraints) gripper based on active sensing about the displacement of its joints, in order to control the trajectory of objects grasped outside the workspace. The gripper has fingers composed of two cylinders in parallel, the translation and rotation of which are independently driven. This characteristic gives a dynamic decoupled behavior to the gripper, and makes it compliant to open during a close motion, or to rotate against the actuated direction, when forced by the inwards movement of the object. The algorithm presents a high level of tolerance concerning uncertainties about the object's position, weight and shape. The kinematics, design concept and control algorithm of the gripper are discussed in detail.
Dexterous manipulation; active sensing; robot hand; control algortithms
