Development of a Conveyor-Type Object Release Mechanism for a Parallel Gripper with a Mushroom-Shaped Gecko-Inspired Surface

A surface microstructure that mimics the surface of a gecko's foot can exert a large gripping force with a small contact force. If such a structure is applied to the fingertips of a two-fingered parallel gripper, stable grasping can be achieved independent of the wetting and frictional state of the contact surface. However, the adhesive force of the microstructure is large while releasing the object, which hinders the release of the object. In this study, we developed a release method using a conveyor mechanism that easily peels off in the direction of rotation with a focus on the characteristics of the micro-protrusion structure. This mechanism is driven in conjunction with the gripper's grasping and releasing motions. Our experiments confirmed that the gripper can stably release the object using the proposed mechanism. The proposal in this paper is a mechanism that dynamically changes the adhesive force on a fingertip by mechanically switching the surface state in accordance with the gripper's grasping and releasing states. This idea can be applied to not only surface microstructure such as gecko-inspired surfaces but also adhesive surfaces such as adhesive tape, and provides novel knowledge in the field of robotics as a method of mechanically changing the fingertip adhesive force.