Toward interpretation of forces in compliant contact for recognition of grasped object

Autonomous grasping is defined as the ability of the robotic system to grasp and manipulate objects with less interruption from higher level controller. This paper presents a method which can be used toward interpreting the contact force/moment measurements in recognising the shape and attributes of the grasped object using a dexterous mechanical end-effector. In this method, the design of finger-tips and finger segments of the end-effector incorporate force/moment sensing transducers and each finger is covered with visco-elastic material. A method for interpreting the compliant type contacts is presented and is based on a novel approach proposed previously by the author with some experimental results. To recognize the object, a set of pre-grasping and grasping strategies are proposed. The end-effector first approaches the object with wide-open pre-grasp configuration. Then, by sequentially closing each segment starting from the one closest to the palm toward the ones further away until the contact is established and identified. By recording the joint positions, contact locations and the types of contact, a grasp configuration can be modelled. Then, by comparing the current grasp configuration with the stored ones, the grasped object can be identified