A topology optimisation based design of a compliant gripper for grasping objects with irregular shapes

Complex steel structures such as power transmission towers require regular inspection and maintenance during their lifetime. This work is currently completed by teams of human workers who climb the live structures. The exposure of these workers to the risks of climbing and completing work on towers provides motivation for developing a robotic substitute. There are many complex elements of climbing power transmission towers, such as the variation in beam shapes, sizes and orientations. To the best of our knowledge, there is no existing robotic grasping solution that can be directly used in this complex environment. This paper presents a topology optimisation based design of a compliant gripper for grasping objects with irregular shapes such as the beam members found in power transmission towers. The structure of the gripper is obtained through the use of a modified topology optimisation model where stiffness constraints are implemented in the optimisation to increase the strength of the gripper in desired areas. The stiffness constrained topology optimisation produces a novel gripper design which is validated through both simulations and physical testing of the manufactured gripper on a variety of physical objects.