A study into kinematics and dynamics of tail-supported climbing in birds and robotics

This work explores the dynamics of actively using a tail for climbing a vertical surface. In nature, woodpeckers, woodcreepers and treecreepers climb vertical tree trunks suspended by their feet and supported by their tail. Videos of these climbing birds are analysed. In general, the stride is initiated by the body pitching forward while simultaneously moving towards the trunk and accelerating up before lifting off. A 2D planar rigid body model is presented and the trajectory for the minimal cost of transport is determined by solving a constrained nonlinear problem. The limiting factors and driving parameters of this legged locomotion gait are investigated. The locomotion efficiency reduces when the jump height and jump time approach the ballistic limit. This work gives a first step towards understanding the role of tail support in climbing dynamics.