Meso-scale compliant gripper inspired by caterpillar's proleg

We propose a biomimetic gripper, inspired by a caterpillar's proleg, that can reliably grip dusty and rough terrain. A caterpillar's proleg makes this possible by using a retractor muscle that opens and closes the proleg, and a planta that gives compliance to the proleg. We implement these components with shape memory alloy (SMA) coil actuators and flexure joints. The gripper is fabricated using composite links and flexure joints. This method replaces metal-based joints and links with flexure joints and composite-based rigid links. The composite-based design provides a simple, light weight, and compact structure that enables the gripper to be applied to small-scale robots. Modeling and experiments are used to analyze the gripping force. The results show how the gripping force changes depending on the length of the flexure joint. A prototype was built to demonstrate reliable gripping on a rough-surfaced block using an adaptive mechanism.