基于激光雷达的农业机器人导航控制研究

Navigation of an Agricultural Robot Based on Laser Radar

以农业机器人为平台,利用激光雷达研究农业机器人在有行株距的果树与有行无株距的树木行中,特别是一侧存在行缺失情况下的导航性能。根据激光雷达获得的树行信息,机器人控制系统进行导航路径计算,确定机器人的横向偏差与方向偏角。利用模糊控制算法实现机器人的导航控制。在无株距且一侧存在4 m距离缺失的冬青树行间及在有行株距且一侧存在6.2 m距离缺失的梨树行间,分别进行3次重复的导航性能试验。试验结果表明,在整个试验距离内冬青树行距与梨树行距都不均等的试验条件下,在冬青树间的最大横向偏差为17.5 cm,在梨树间的最大横向偏差为28 cm。在一侧冬青树出现缺失时对机器人的导航性能影响较小,而在一侧梨树缺失时对机器人的导航性能影响较大。根据横向偏差的统计值与机器人行驶轨迹,表明控制算法能够控制机器人沿着中心线行驶。

The navigation performance was studied for an agricultural robot based on laser radar between the crop rows with intra-row spacing and without intra-row spacing, especially in the absence of one-side crop row. According to the crop information from the laser radar, the different navigation methods were developed to calculate navigation path and thus to determine the lateral error and heading angle error for the different type of the crop rows. Then the fuzzy logic control was used to control the robot to travel along the calculated navigation path. Tests were conducted in three replications respectively while the robot traveled between the evergreen tree rows with a missing distance of 4 m in one side and the pear tree rows with a missing distance of 6.2 m in one side. Results showed that, the robot traveled successfully, with the maximum navigation errors of 17.5 cm and 28 cm for the evergreen tree tests and the pear tree tests respectively, when the inter-row spacing of the evergreen trees and the pear trees were not fixed in the respective test distance. Meanwhile, the missing distance in one side for the evergreen trees had no significant effect on the traveling of the robot, but it seemed to have an effect for the missing distance of the pear trees. According to the statistic data of the tests and the robot trajectories, it was shown that the control algorithm had ability to make the robot travel along the centerline of the crop rows.