A Sarrus-Based Passive Mechanism for Rotorcraft Perching

This work examines a passive perching mechanism that enables a rotorcraft to grip branchlike perches and resist external wind disturbance using only the weight of the rotorcraft to maintain the grip. We provide an analysis of the mechanism's kinematics, present the static force equations that describe how the weight of the rotorcraft is converted into grip force onto a cylindrical perch, and describe how grip forces relate to the ability to reject horizontal disturbance forces. The mechanism is optimized for a single perch size and then for a range of perch sizes. We conclude by constructing a prototype mechanism and demonstrate its use with a remote-controlled (RC) helicopter.