Design and Performance Analysis of Monitoring System for Seed Metering and Fertilization of Precision Seeder Based on Photoelectric Sensor

In order to realize accurate monitoring of wheat sowing and fertilization process and ensure efficient and reliable sowing operation, an integrated monitoring system of wheat sowing and fertilization based on variable-distance photoelectric sensor is designed. The monitoring system includes the hardware circuit of STM32F103 lower computer and the human-machine interface of the upper computer touch screen. The hardware circuit of the lower computer is composed of OH-1021 photoelectric sensor, signal shaping and amplifying circuit, encoder speed acquisition module, communication module, central processor, and peripheral circuits. The information of seed fertilizer flow and seed fertilizer shaft rotation is obtained through the reflective photoelectric sensor and rotary encoder respectively to judge the running state of sowing. The information is transmitted to the human-machine interface of the upper computer touch screen of MCGS by means of Modbus communication protocol. In the experimental species, the single seed monitoring accuracy of the monitoring system reaches 98.6%. Compared with the test results of the performance test bench of the seed metering device, the monitoring error of the monitoring system is less than 0.3%, the monitoring error of the replay rate is less than 0.6%, and the monitoring accuracy of the seeding amount is greater than 94%. The simulation results of the seed metering monitoring circuit of the lower computer show that the detection distance of the amplifier circuit to the photoelectric sensor of the seed tube changes by [4 mm, 7 mm]. The communication test results of the upper and lower computers show that the accuracy of data transmission reaches 100%, the monitoring system shows that the accuracy of fault detection exceeds 90%, and the response time of lacking, blocking, and leaking is less than 0.3 s. The monitoring system realizes high-precision monitoring of wheat seed metering and fertilization, which is helpful to improve the quality of wheat planting.