果园作业机器人的自主行间导航系统研究

Autonomous inter-line navigation system for orchard robots

关键词:  果园行  自主导航  激光雷达  果园作业机器人

Key words:  orchard row  autonomous navigation  lidar  orchard operation robot

摘要:

【目的】挂载多种农机具的果园作业机器人能减少果园劳动力投入、降低水果生产 成本并提高果园生产效率，其中自主导航系统是果园作业机器人应用研究的重点和难点。 【方法】文章针对果园作业机器人GPS导航过程中定位信号易受树叶遮挡及多路径效应干扰 等问题，以果园作业机器人初始位置为原点建立世界坐标系，采用拓展卡尔曼滤波算法对 通过三维激光雷达结合RANSAC算法获取的果园行直线进行优化，设计结合差速模型和纯 跟踪算法的果园自主行间导航算法，并以该算法为基础开发果园作业机器人自主行间导航系 统，驱动果园作业机器人沿树行中心行驶并完成自主调头进入下一行的工作。【结果】 （1）根 据现代化矮化密植果园的环境，果园自主行间导航算法能根据两侧果树行的三维点云，自主 生成稳定的导航位置；（2）果园作业机器人能够沿果园行中心位置匀速行驶，并能够实时根 据果园行的变化来修正自身的位姿。当速度在0.4 m/s时候，机器人运动的横向平均偏差为 0.1 m，航向平均偏差为1.04°；（3）基于果园行宽相等的条件，果园作业机器人能够在行尾 自主调头进入下一行，之后沿行内中心位置继续行驶。【结论】该文果园自主行间导航系统 设计合理，算法稳定性高，导航精度高，不受驾驶路况的影响，能够满足现代化矮化密植果 园作业的自主行驶需求。

Abstract:

［ Purpose］There are a large number of tasks that are repeated and labor intensive in the production process of the orchard. Nowadays，the labor cost of orchard is rising rapidly and the quantity is gradually decreasing. In order to reduce the labor input of the orchard and the cost of fruit production，the orchard operation robot is used to assist the production operation by mounting a variety of agricultural machinery and autonomous navigation，which is an important production choice with low-cost and high-efficiency. ［Method］The basis of orchard operation robot is the ability to navigate autonomously in the orchard. Given the positioning signal is easily interfered by leaf occlusion or multi-path effect during the process of GPS-based navigation，this reserch builds the world coordinate system whose origin is the initial position of the orchard robot before entering the fruit tree row. Then it combines the 3D Lidar data with the RANSAC algorithm to obtain the orchard line and record it in the world coordinate system. Next，the EKF algorithm is used to obtain a more robust orchard line. Finally，the differential model of the orchard operation robot is combined with the pure tracking algorithm to drive the orchard operation robot along the center of the row at a speed of 0.4 m/s，and it can turn to the next row and continue to work. ［Result］ （1）According to the environment of modern dwarf dense orchard，the algorithm in the article can independently generate stable navigation position according to the three-dimensional point cloud of fruit trees on both sides；（ 2）Orchard operation robot can drive along the center of orchard and is able to correct its pose in real time based on changes in the orchard rows. When the speed is 0.4 m/s，the lateral average deviation of the robot motion is 0.1 m，and the average heading deviation is 1.04°；（ 3）Based on the condition that the orchard row width is equal，the orchard operation robot can automatically turn to the next row at the end of the current row. Then continue driving along the center of the row. ［Conclusion］The autonomous navigation system of the orchard operation robot in the article is reasonable in design，moreover，it has high stability in algorithm，high accuracy in navigation，and is not affected by driving road conditions，which can meet the autonomous driving demand of dwarf dense planting orchard operation.