Pruning branches of apple trees is a labor-intensive task. Pruning robots can save manpower and reduce costs. A full map of the apple orchard with collision-free paths, which is navigation planning, is essential. To improve the navigation efficiency of the apple tree pruning robot, an improved RRT-Connect algorithm was proposed. Firstly, to address the disadvantage of randomness in the expansion of the RRT-Connect algorithm, a goal-biased strategy was introduced. Secondly, to shorten the path length, the mechanism of the nearest node selection was optimized. Finally, the path was optimized where path redundancy nodes were removed, and Bezier curves were used to deal with path sharp nodes to further reduce the path length and improve the path smoothness. The experimental results of apple orchard navigation show that the improved algorithm proposed in this paper can cover the whole apple orchard, and the path length is 32% shorter than that of the RRT-Connect algorithm. The overall navigation time is 35% shorter than that of the RRT-Connect algorithm. This shows that the improved algorithm has better adaptability and planning efficiency in the apple orchard environment. This will contribute to the automation of orchard operations and provide valuable references for future research on orchard path planning.

In South China, the tropical weather and climate result in severe sugarcane lodging problems which greatly hinders sugarcane mechanical harvesting. The main function of the crop divider is to lift lodged canes and facilitate base-cut cane feeding. In this study, a series of field tests were conducted on crop dividers of Liugong 4GQ-180 sugarcane chopper harvester. The tests were designed to identify the relationships of the performance index (maximum lifting height of sugarcane) and the main influencing factors (machine forward speed, rotational speed of inside scrolls, and ground clearance of crop divider toes). The single factor test was conducted to determine optimum range of these test factors: the forward speed (FS) was 2.0-4.0 km/h, the rotational speed of inside scrolls (RS) was 100-140 r/min, and the toe ground clearance (GC) was 0-5 cm. The orthogonal test (three factors and three levels) was carried out to determine the optimal combination of operating parameters: FS was 2.0 km/h, RS was 115 r/min, and GC was 0 cm. In addition, the range analysis of orthogonal test results revealed that the order of each test factor affecting crop divider performance was RS, FS, GC. This study was expected to provide valuable references for the optimal operation of sugarcane harvester crop dividers. Keywords: sugarcane chopper harvester, parameter optimization, machine forward speed, rotational speed of scrolls, ground clearance, maximum lifting height, field test, evaluation, crop divider DOI: 10.25165/j.ijabe.20211401.5621 Citation: Bai J, Ma S C, Wang F L, Xing H N, Ma J Z, Hu J W. Field test and evaluation on crop dividers of sugarcane chopper harvester. Int J Agric & Biol Eng, 2021; 14(1): 118–122.