Abstract
In spruce forests, to maintain the ecological health and preventing wildfire, a proper spruce-tree pruning is a possible solution. Moreover, pruning activities allow to improve the quality of the timber. In this work, the development of a climbing robot for pruning spruce trees is considered evaluating, in particular, the climbing, sensing and cutting/pruning phases. After a preliminary analysis of the robot requirements, a concept for a climbing robot for spruce-pruning has been developed and a functional design iteratively improved for allowing proper locomotion and stability. The capability of the system to sense the environment and properly recognize the branch position and diameters also under hard environmental conditions is here focused comparing the characteristics of different sensing solutions. A series of experimental tests have been considered to evaluate the sensors in terms of localization accuracy, influence of ambient and incident light, influence of dust and dirt presence. The results will serve as basis for the further development of the robotic system.