Design and Analyses of a Novel Reconfigurable Logging Branch Mechanism

Abstract

A reconfigurable logging and branch-lopping mechanism has been designed to shorten the production cycle, reduce work intensity, and improve labor survival rate in the logging industry. The mechanism integrating logging and branch-lopping functions can flexibly morph into three con-figurations, namely, series, parallel and mixed, as well as eight structure states to satiate different requirements. Not only does it possess sufficient stiffness to fell large trees but it also offers high flexibility to trim and crop small branches which superior performance has relatively wide engineering application prospects. The kinematics and static stiffness of the mechanism are the key techniques for its engineering application. With the mechanism as the research object, the working principles were analysed and the adjacency matrix of each structure state was presented. The Screw Theory and CGK formula were deployed to calculate the degrees of freedom of some of the structure mechanisms. The kinematics of some of the structure states was analysed and their flexibility matrices were obtained with vector algebra. The static stiffness of two structure states was compared indirectly by contrasting their flexibility matrices before their kinematics was simulated numerically. Engineering application of the mechanism in welding robots, robots that pick up objects, cleaning robots and other fields is demonstrated towards the end of this paper.