Grasping and dynamic manipulation by soft finger-tips without object information

By several years, the robotic fingers have been studied using rigid finger-tips to grasp and manipulate an object. Recently, hemispherical soft finger-tips have been used in order to enhance dexterity of the robotic hands where the high friction contact between them, prevents the slipping and improves the grasping stability. In this paper is presented, a new control for grasping and object manipulation under assumption that kinematic parameters of the object and the contact point location between object and finger are unknown. This approach is based on the assumption that the contact must vary depending the rolling contact constraint and taking into account a normal and tangential deformations in the soft finger-tips. A critical role for the establishment of our approach is the distance between center position of the finger-tip and the straight line that crosses the object perpendicularly which should be zero. Simulation results are provided to visualize the stable grasping and some manipulation tasks as the rotation and translation of the object on a pair of soft fingers with three degree of freedom.