Releasing tool-adhered natural fibrous microscale objects with vacuum system

Abstract

This paper presents a novel method for releasing natural fibrous microscale objects from a microrobotic end-effector. A vacuum system is introduced to help overcome the adhesive force between a microgripper and a fiber, and realize a successful releasing process. Ten releasing tests were done using three humidity values: 25%, 55% and 85%. The test results show that 100% release rate was achieved in humidities of 25% and 85%. In humidity of 55%, the release rate was 90%. One special failure occurred at 55% humidity, in which the fiber was adhered to one of the gripper tips after opening both grippers, and inclined about 35º to the horizontal line. This angle decreased the vacuum effect on the fiber and failed the releasing process. The results suggested that 100% release rate can be achieved by increasing the vacuum force or adding another degree of freedom to the microgrippers, which allows them to rotate in x-z or y-z plane to neutralize the angle between the fiber and the horizontal line.