黄东岩,朱龙图,贾洪雷,于婷婷.基于压电薄膜的免耕播种机播种深度控制系统[J].农业机械学报,2015,46(4):1-8.
Huang Dongyan,Zhu Longtu,Jia Honglei,Yu Tingting.Automatic Control System of Seeding Depth Based on Piezoelectric Film for No-till Planter[J].Transactions of the Chinese Society for Agricultural Machinery,2015,46(4):1-8.
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基于压电薄膜的免耕播种机播种深度控制系统   [下载全文]
Automatic Control System of Seeding Depth Based on Piezoelectric Film for No-till Planter   [Download Pdf][in English]
投稿时间:2014-12-27  
DOI:10.6041/j.issn.1000-1298.2015.04.001
中文关键词:  免耕播种机  播种深度  自动控制  压电薄膜  单片机
基金项目:“十二五”国家科技支撑计划资助项目(2014BAD06B03)和吉林省科技发展计划资助项目(20130206007NY)
作者单位
黄东岩 吉林大学
吉林农业大学 
朱龙图 吉林农业大学 
贾洪雷 吉林大学 
于婷婷 吉林农业大学 
中文摘要:为使免耕播种机在秸秆覆盖地作业时自动保证播种深度的一致性和稳定性,设计了一种主动作用式播种深度自动控制系统。采用聚偏二氟乙烯(Polyvinylidence fluoride,PVDF)压电薄膜传感器将免耕播种机限深轮的胎面形变量转换为电压信号,信号处理电路对传感器产生的信号放大滤波,提取信号峰值,系统根据峰值信号实时监测播种单体对地表的压力,控制信号形成电路在压力不足时发出控制信号,控制安装在播种机机架与播种单体四连杆间的空气弹簧产生推力,使播种单体能够产生对地表的压力,从而保证播种深度的一致性。试验结果表明,所设计的主动作用式播种深度自动控制系统能够精确控制开沟深度,仿形性能可靠,作业速度为5~8km/h时,播深合格率达到90%,作业速度大于8km/h时,播深合格率明显高于被动作用式播种深度控制装置。
Huang Dongyan  Zhu Longtu  Jia Honglei  Yu Tingting
Jilin University;Jilin Agricultural University,Jilin Agricultural University,Jilin University and Jilin Agricultural University
Key Words:No-till planter  Seeding depth  Automatic control  Piezoelectric film  Chip microprocessor
Abstract:Conservation tillage effectively protects the environment. A no-till planter can seed on the straw mulching farmlands, and it is the most important machine in conservation tillage. In order to make sure the consistency of sowing depth, an active seeding depth control system was designed for a no-till planter. The system was consisted of piezoelectric film sensor, a signal processing circuit, a control signal generating circuit and a pneumatic drive system. When planting with a conventional row crop planter which had a plurality of row units mounted on a toolbar, it was necessary to provide a sufficient down force on each row unit to ensure that the seed trench opener was fully penetrated into the soil. Proper down force was also essential to provide proper amount of soil compaction in the side walls of the seed trench. Seeding depth primarily depended on the down force on each row unit. In order to make adjustments to the down force in real time, it was needed to measure the magnitude of the down force on an ongoing basis. The piezoelectric film sensors were used for measuring the deformation of depth limit wheel, the down force of the row unit was monitored in real time according to the deformation of the limit wheel. The piezoelectric film generated charge during rotating of the wheel. The sensor changed the charge into a voltage signal. The voltage signal was processed by low-pass filter and preamplifier circuit in order to eliminate the noise and amplifiy the filter, and then the peak-holding circuit gained the peak voltage value which was sampled by A/D conversion and sent to control signal generating circuit by the wireless transmitter. Wireless receiver received the digital signal which was compared with the present value stored in the microcontroller, if the received signal was less than the present value, the difference between the received signal and the present value formed the control signal. The pneumatic drive system was consisted of air compressors, tank, filters, electric-gas proportional valve and air spring. To provide the necessary down force, an air spring was assembled at the linkage which was mounted in the row unit to the toolbar. Compressed air was generated by the air compressor and stored in the tank, and then the compressed air was filtered to filter out dust and impurities. Pure compressed air was fed to the electric-gas proportional valve; the output of electric gas proportional valve was connected to the air spring. The output gas pressure of the electric gas proportional valve was controlled by control signal, the air spring can generate corresponding down force on the unit row. A field experiment was conducted to verify the performance of the seeding depth automatic control system, and the result showed that the seeding depth control system can provide accurate ditching depth and reliable performance of profiling. When the speed of the planter was over 8km/h, the qualified sowing depth rate of the active seeding depth control system was much better than that of the passive control system.

Transactions of the Chinese Society for Agriculture Machinery (CSAM), in charged of China Association for Science and Technology (CAST), sponsored by CSAM and Chinese Academy of Agricultural Mechanization Science(CAAMS), started publication in 1957. It is the earliest interdisciplinary journal in Chinese which combines agricultural and engineering. It always closely grasps the development direction of agriculture engineering disciplines and the published papers represent the highest academic level of agriculture engineering in China. Currently, nearly 8,000 papers have been already published. There are around 3,000 papers contributed to the journal each year, but only around 600 of them will be accepted. Transactions of CSAM focuses on a wide range of agricultural machinery, irrigation, electronics, robotics, agro-products engineering, biological energy, agricultural structures and environment and more. Subjects in Transactions of the CSAM have been embodied by many internationally well-known index systems, such as: EI Compendex, CA, CSA, etc.

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