DESIGN AND EXPERIMENT OF AN AUTOMATIC GIRDLING DEVICE FOR ECONOMIC TREE TRUNK INSPIRED BY CAM MECHANISM

Abstract

In order to solve the problem of complicated processes, low efficiency and high cost of economic tree trunks girdling, inspired by cam mechanism this study developed a new type of automatic half-ring girdling device, which can automatically complete a series of operations, including the tree trunk profile scanning, girdling trajectory calculating and automatic bark cutting. A pair of laser rangefinders and guide screws were symmetrically arranged on a half-ring rotating rail, which could rotate around the tree trunk, and two chainsaws assembled above the guide screws were controlled to move radially. The laptop was used as upper computer, and a 4-axis motion control card was used as the lower computer, which constituted the control system of precise movement. The programs of the tree trunk profile scanning, the xylem profile curve fitting and the chainsaw centre trajectory calculation were designed in LabVIEW. The scanning tests and girdling experiments were carried out on the different sections of the tree trunks in the laboratory. The feasibility of the automatic girdling device for economic tree trunks was verified with one complete and automatic girdling operation finished by this device, which took 150 seconds, and the error range of automatic girdling was within ±2mm. This device improves the automation degree of girdling operation and provides a support for the development of economic forestry.