A System for Fruit Tree Canopy Characters Measuring Based on CAN-bus

Measuring of fruit tree canopy parameters were required for site-specific management of fruit orchard such as estimation of fruit yield, variable rate application of fertilizer and pesticides precisely on each tree. For riding the effect cased by tractor deviation in driving path between two rows of trees and uneven ground, measuring was designed based on CAN bus, combined robot navigation technology, including AHRS and DGPS-RTK, with the measuring of fruit tree canopy characters, and used C8051F040 micro controller as node ECU. The hardware circuit was introduced in detail, the forming of CAN transmission information frame and software were also analyzed. Experiment with litchi trees in orchard using four ultrasonic sensors showed that system was stable, having highly repeatability (R²=0.9341, RMSE=1.22m³) and accuracy (R²=0.8972, RMSE=1.766m³) of canopy volume measuring.