基于RTK测速的油菜直播机随速可控可调排种控制系统研究

Variable-rate Seeding Control System Based on RTK Speed Measurement for Rapeseed Direct Seeder

摘要:

针对油菜精量直播机连续作业过程中设定作业速度条件下，作业速度波动导致排种量与目标播量不一致的问题，设计了一种基于“RTK测速+落种检测+电机实时调控”的油菜精量直播机随速可控可调排种控制系统，确定了影响调速性能的关键参数，构建了步进电机调速模型；运用GNSSToolKitLite上位机开展ZED-F9P GNSS模块静态速度漂移试验，得到该模块静态速度漂移量服从均值为0.054 m/s、方差为0.029 m2/s2的正态分布。利用自动数粒仪与JPZS-16型排种性能试验台进行试验，得到正负气压组合式排种器转速为5~60 r/min时，落料计数器播种量检测值与实际值平均绝对误差小于10%；通过台架试验确定了不同排种器调速模型，得到不同排种器最佳工作转速、电机转速与目标播量的函数关系。不同排种器随速控制适应性台架试验结果表明：当作业速度为3~12 km/h时，系统搭载高速机械离心式与油麦兼用气送式排种器总排量稳定性变异系数小于1.21%。田间试验结果表明：当作业速度为5~12 km/h时，本系统搭载高速机械离心式与窝眼轮式排种器总排量稳定性变异系数小于9.7%，满足随速播种要求，可为油菜精量播种控制系统结构改进提供参考。

Abstract:

A precision rapeseed seeder with continuous operation often faces the problem of inconsistent sowing quantity with the target seeding rate due to fluctuations in operating speed. To address this issue, a control system for precise rapeseed seeder, based on “RTK speed measurement + seed drop detection + real-time motor control,” was designed. Key parameters affecting the speed control performance were analyzed, and a stepper motor speed control model was established. Static speed drift tests were conducted by using the ZED-F9P GNSS module with the GNSSToolKitLite software. The analysis determined that the static speed drift of the module followed a normal distribution with a mean of 0.054 m/s and a variance of 0.029 m2/s2. The performance tests with an automatic seed particle counter and the JPZS-16 seeding performance test bench determined that the average absolute error between the seeding quantity detection value of the positive and negative pressure seeders and the actual value was less than 10% when the rotation speed was ranged from 5 r/min to 60 r/min. The speed control models for different seeders were determined through bench tests, and the functional relationship between the optimal operating speed range of different seeders and the motor speed with the target seeding rate was analyzed. The adaptability bench tests for different seeders demonstrated that when the operating speed was ranged from 3 km/h to 12 km/h, the total displacement coefficient of variation for the system equipped with a high-speed mechanical centrifugal seeder and a combined air-assisted seeder for rapeseed and wheat was less than 1.21%. Field tests showed that when the operating speed was ranged from 5 km/h to 12 km/h, the total displacement coefficient of variation for the system equipped with a high-speed mechanical centrifugal seeder and a furrow press wheel seeder was less than 9.7%, meeting the requirements of variable-rate seeding. This system can serve as a reference for improving the structure of precision rapeseed seeding control systems.