Bistable compliant underactuated gripper for the gentle grasp of soft objects

Abstract

This paper presents the design of an underactuated gripper with an embedded bistable mechanism. This gripper is specifically targeted at seizing soft objects while minimizing the deformation of the latter. Decreasing the magnitudes of these deformations is key in many practical applications to reduce potential damages due to excessive contact pressure. For instance, for both food processing and medical applications bruising the manipulated item is usually unacceptable. The gripper presented in this work aims at solving this issue by taking advantage of a recently published new method to accurately model the interactions between a compliant gripper and a deformable object. The method is also extended to include contact with the palm of the gripper. The main advantage of this technique compared to existing traditional approaches such as finite element analyses (FEA) is its computational efficiency which allows its use in demanding optimization algorithms, as will be shown. In the first part of this paper, the overall design of the gripper is proposed and the corresponding model is described. The optimization process is then presented and completed with the experimental testing of a prototype.