Applying fuzzy logic to tree bucking control

In this article, we introduce a fuzzy logic based control system that calibrates the price list controlling the tree bucking of a modern harvester according to the unique conditions of an individual stand prior to harvesting. The system employs a bucking simulator that predicts an output distribution for any price list generated. A fuzzy controller is used to recalculate the price list according to the difference between the demand distribution and the actual output distribution. The tests with perfect knowledge of the stems showed that the control system clearly works efficiently. However, calibrating the price list prior to harvesting seemed to be very sensitive to the precision of the prior information on the trees. The simulations showed that while no gain can be achieved by preharvest inventorying of the stands and fine-tuning the price lists with this imperfect knowledge, the same or even better bucking results can be obtained by the bucking-to-demand process in which the price list is continuously adjusted after each cutting.