基于双闭环PID模糊算法的玉米精量排种控制系统设计

黄淮海麦玉轮作区秸秆全量还田模式下,小麦秸秆韧性好、粉碎还田效果差以及土壤较为黏重,传统被动式地轮驱动易秸秆缠绕、拥堵及黏土量较大,播种作业易断条。为有效解决这些问题,该文以勺轮式玉米排种器为研究对象,设计一种主动式玉米电控精量排种系统。该系统作业时,通过USART HMI四线制触控串口屏人机界面向控制器输入理论期望株距,由GPS测速传感器采集机具作业速度,结合旋转编码器实时采集排种器作业转速,基于双闭环模糊算法对PID参数进行自整定,得到排种器目标转速,通过控制器调节相应PWM占空比,以实现通过机具作业速度实时控制电机转速,实现精密排种。台架试验结果表明:理论排种转速6~54 r/min时,实际转速的变异系数均小于10.0%,实际转速在理论转速附近波动范围小,符合控制要求;在设定株距值下,车速为3~5 km/h时,株距合格指数94.0%,漏播指数3.0%;车速为6~8 km/h时,株距合格指数≥90.0%,漏播指数≤4.5%。田间验证结果表明该玉米排种控制系统作业时,株距合格指数≥87.75%,平均值为90.89%,漏播指数均小于4%,平均值为2.54%,与市场上常见的勺轮式玉米排种器相比合格指数提高2.12个百分点、漏播指数降低4.32个百分点,播种性能良好,满足玉米农艺种植要求。该文研究的玉米电控精量排种系统可有效提高排种质量并可为研制高速精量主动排种控制系统提供参考。

Design of control system of maize precision seeding based on double closed loop PID fuzzy algorithm

Abstract: Under the full amount of straw returning mode for wheat-maize rotation cropping areas in Huang-Huai-Hai Plain of China, not only the wheat straw mulch in the field is large, but also it has good toughness, and the effect of straw grinding is poor. In addition, the soil is more viscous. When the field operation is driven by the traditional wheel drive, it is easy to have straw winding and congestion, which is easy to break when seeding. At present, the corn seeder mainly adopts the ground wheel driving seeder and pneumatic seeder, and the land wheel driving seeder is transmitted by the earth wheel, driving the seed row shaft to rotate and arrange seeds, When the field soil viscosity and straw coverage are large, the driving part can not work normally. Pneumatic corn planter is mostly used in large farms, which are more expensive and not suitable for domestic use. In order to reduce the rate of missed seeding and improve the precision of maize sowing, it is necessary to develop a reliable and active corn precision seed metering control system. To solve these problems effectively, this paper takes a common spoon-wheel corn seeding device in the market as the research object, and a kind of active electronic control corn seeding meter system is designed. This electronic control system consists of control box, touch display interface, rotary encoder, GPS speed sensor, brushless DC motor, driver and commutator reducer. When the system works, the USART HMI four-wire touch serial port man-machine interface is used to input the theoretical expectation of the controller to the controller, using the GPS speed sensor to collect the working speed of the machine, in combination with rotary encoder, and the operation speed of the feeder is collected in real time. To ensure the quality of work and improve the ability to resist interference, based on the double closed-loop fuzzy algorithm, the PID parameters are self-adjusted to get the target speed of seed metering device. The corresponding PWM duty cycle of the controller is adjusted to achieve the real-time control of the motor speed through machine operation speed and achieve precise seed metering. The results of bench test showed that the variation coefficient of the actual rotational speed was less than 10.0% when the theoretical rotation speed was 6 ~ 54 r/min, and the actual rotational speed was small in the vicinity of the theoretical rotational speed, which met the control requirements. When the speed was 3 ~ 5 km/h under the set spacing value, the plant distance qualified index was > 94.0%, and the leakage index was < 3.0%. When the vehicle speed was 6 ~ 8 km/h, the plant distance was greater than 90.0%, and the seeding index was less than 4.5%. Field validation results showed: under the full amount of straw returning mode for wheat-maize rotation cropping areas in Huang-Huai-Hai Plain, when the maize row control system was in operation, the qualified index was greater than 87.75%, and the average was 90.89%, and the seeding index was less than 4%, with an average value of 2.54%. In comparison with the common spoon-wheel corn seeding device in the market, the qualified index was increased by 2.12 percentage points, and the seeding index was decreased by 4.32 percentage points, and the seeding performance was good, which met the requirements of corn agronomic planting. Under the full amount of straw returning mode for wheat-maize rotation cropping areas in Huang-Huai-Hai Plain of China, not only the wheat straw mulch in the field is large, but also it has good toughness, and the effect of straw grinding is poor, and in addition, the soil is more viscous. In this paper, the research of electronic control system for seed meters for maize planting can effectively improve the quality of the row and provide a reference for the development of high speed actuator control system.