Design, modelling and simulation of soft grippers using new bimorph pneumatic bending actuators

Abstract

Soft compliant grasping is essential in delicate manipulation tasks typically required in manufacturing and/or medical applications to prevent stress concentration at the point of contact. In comparison with their rigid counterparts, the intrinsic compliance of soft grippers offers simpler control and planning of the grasping action, especially where robots are faced with a number of objects varying in shape and size. However, quantitative analysis is rarely utilized in the design and fabrication of soft grippers, due to the fact that significant and complex deformation occurs once the soft gripper is in contact with external objects. In this paper, we demonstrate the design of a soft gripper using our novel bimorph-like pneumatic bending actuators. The gripper was modelled through finite element analysis to reflect its gripping capability during interaction with certain targeted objects. The proposed systematic design and analytical model was validated via experiments. The system's gripping capability was evaluated with objects of different weight and dimension. In addition, compliance testing has proved that the proposed soft gripper is able to grip objects of 60 g from the side, without causing exceeding concentration stress on the targeted object.