基于压电冲击法的水稻穴直播监测系统设计与试验

为精准实时监测水稻穴直播机播种状态,提高监测稳定性,以弹射式耳勺型水稻穴直播排种器为研究载体,采用PVDF压电薄膜为传感元件,以ATmega328P MCU控制器为核心,基于压电冲击法设计了水稻穴直播监测系统。通过分析种群投种轨迹,设计了可辅助监测且导种成穴的导种管,确定了PVDF压电薄膜传感器的安装部位。结合排种器多粒穴播作业特点,确定了4种作业故障监测算法。设计了系统硬件电路,开发了蓝牙无线串口传输APP,实现了上、下位机无线通信。台架测试表明:在不同工况下系统灵敏度均在90. 83%及以上,可实现对信号的有效采集。由田间试验得到系统的重播监测精度、漏播监测精度及有效监测精度的平均值的最小值分别为81. 79%、80. 42%和97. 67%,且系统在机具发生重播或漏播时可进行声光报警。该监测系统满足水稻穴直播监测要求,有助于提高水稻穴直播作业质量。

Design and Experiment of Monitoring System for Rice Hill-direct-seeding Based on Piezoelectric Impact Method

In order to accurately monitor the sowing state of rice hill-direct-seeding machine in real time and improve stability, taking rebound dipper rice hill-direct-seeding metering device as research carrier, PVDF piezoelectric film as sensing element, ATmega328P MCU as control core, a monitoring system for rice hill-direct-seeding based on piezoelectric impact method was designed. Based on analysis of seed throwing trajectory of rice seeds, seed-conducting tube which could be used to assist monitoring and indenting seed-conducting was designed, and the installation position of PVDF piezoelectric film sensor was determined. The control algorithm to four kinds of seeding faults was determined with characteristics of multi-seed hill-direct-seeding. The whole hardware circuit of system was designed and Bluetooth wireless serial transparent transmission APP was developed, so that wireless communication between the host computer and the slave computer could be realized. The results of bench test showed that the sensitivity of system can reach more than 90.83% under different working conditions, so the system can realize the effective capture of signal. The field performance experiment results showed that acousto-optic alarm operation can be done when fault was happened. Counting reseeding hill amount and miss seeding hill amount were shown on Bluetooth wireless serial transparent transmission APP, which were contrast with actual reseeding hill amount and miss seeding hill amount counted by manpower, and the minimum mean values of reseeding monitoring accuracy, miss seeding monitoring rate and effective monitoring rate of system were 81.79%, 80.42% and 97.67%, respectively, which can meet the monitoring requirement of rice hill-direct-seeding and enhance the operation quality of rice hill-direct-seeding.