基于北斗导航的大蒜无人播种机设计与试验

Design and Testing of Unmanned Garlic Seeder Based on Beidou Navigation

摘要:

针对大蒜播种过程中单粒正头播种合格率低、人工驾驶易疲劳、播后整齐度差等问题,设计了一种基于北斗高精度导航的履带式大蒜无人播种机。整机系统由驱动底盘、勺链式取种装置、三级调向正头装置、离合插播装置及控制系统构成,通过北斗RTK/INS融合定位技术实现厘米级路径跟踪,结合端点坐标自标定与全局路径规划算法完成无人化自主作业。为提高播种精度,取种装置采用弧形腔体勺链结构,确保单粒取种率;正头装置采用内壁曲面逐级变化的三级料斗构成,蒜种经“平铺–倾斜–直立”调整后,以鳞芽朝上的直立状态落入插播鸭嘴;为实现导航与播种的高效协同,设计了气缸离合机构,基于实时位姿反馈,控制插播装置启停与压实轮升降,确保转弯调头时播种作业及时中断与恢复。为验证样机性能,进行了田间试验,结果表明,播种机在0.1 m/s的典型播种速度下直线行走50 m时,导航绝对偏移量最大值、最小值分别为32.1、0.44 mm,平均值为11.8 mm;转弯调头作业路径最大、最小绝对偏差分别为40.5、13.5 mm,平均绝对偏差为25.4 mm;平均正芽率、漏播率及重播率分别为95.7%、1.7%、2.2%,满足大田规模化种植的技术需求。

Abstract:

Aiming at the problems of low qualified rate of single seed head seeding, fatigue of manual driving and poor uniformity after sowing in garlic sowing process, a crawler-type garlic unmanned seeder based on Beidou high-precision navigation was designed. The whole machine system consisted of a driving chassis, a spoon chain seed taking device, a three-level direction adjustment head device, a clutch insertion device and a control system. The centimeter-level path tracking was realized through Beidou RTK/INS fusion positioning technology, and the unmanned autonomous operation was completed by combining the endpoint coordinate self-calibration and global path planning algorithm. In order to improve the sowing accuracy, the seed taking device adopted an arc cavity spoon chain structure to ensure the single seed taking rate; the head device adopted a three-level hopper with a step-by-step change of the inner wall surface. After the garlic seeds were adjusted from “flat – tilted – upright”, they fell into the insertion duckbill in an upright state with the phosphorus bud facing up; in order to achieve efficient coordination of navigation and sowing, a cylinder clutch mechanism was designed. Based on real-time posture feedback, the start and stop of the insertion device and the lifting and lowering of the compaction wheel were controlled to ensure timely interruption and resumption of sowing operations when turning. In order to verify the performance of the prototype, field tests were carried out. The results showed that when the seeder walked in a straight line for 50 m at a typical sowing speed of 0.1 m/s, the maximum and minimum values of the navigation absolute offset were 32.1 mm and 0.44 mm, respectively, and the average was 11.8 mm; the maximum and minimum absolute deviations of the turning operation path were 40.5 mm and 13.5 mm, respectively, and the average absolute deviation was 25.4 mm; the average positive bud rate, missed sowing rate and reseeding rate were 95.7%, 1.7% and 2.2%, respectively, which met the technical requirements for large-scale field planting.