Releasing tool-adhered natural fibrous microscale objects with vacuum system

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 35° 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.