Determining “grasping” configurations for a spatial continuum manipulator

Unlike a conventional articulated manipulator, where only the gripper manipulates objects, a continuum manipulator, such as a multi-section trunk/tentacle robot, is promising for deft manipulation of a wide range of objects of different shapes and sizes. Given an object, a continuum manipulator tries to grasp it by wrapping around and squeezing it. A main open problem is how to determine if the object can be grasped and if so, the whole-arm wrapping around configurations of the robot to grasp it, which we call grasping configurations. In this paper, we provide a general and complete analysis of grasping configurations of a spatial continuum manipulator consisting of three constant-curvature sections, for any given 3-D object. We formulate conditions for existence of solutions and describe how to determine valid grasping configurations. Our method can extend to general continuum manipulators of n constant-curvature sections (where n ≥ 3).