Design of Electro-adhesive Gripper for handling of Carbon Fibre sheets

Abstract

With the advent of composite materials, industrial tools for their manufacturing have progressed as well. In handling of cut fabrics involved in composite manufacturing methods, due to the unconstrained nature of the fabric edges, they are susceptible to fraying and disorientation. This can be avoided by use of robotic grippers, that do not use positive locking, or high vacuum pressures. One such gripping method may be electro-adhesion, where localized charge distribution aids in polarizing the fabric which in turn is attracted to the gripper. This paper analyses the ponderomotive pressure developed by such a gripper for a range of values for the number of electrode pairs and the electrode lengths. Optimization of parameters for maximizing the ponderomotive pressure in the constrained contact area of gripper is needed. Two test geometry cases of the picked fabric are considered, to observe the performance of the gripper in picking large sheets, as well as small cut fabrics. The best possible combination of the electrode length and number of electrode pairs is then applied to the test geometry cases. The designed gripper shows a maximum fabric sag of 0.55mm on the geometry cases, which does not contribute to develop a matrix distortion of a large magnitude on the picked fabric object. Such a gripper assembly can be mounted on an articulated robot to pick and place parts of the cut fabric.