播种机气动式下压力控制系统设计与试验
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摘要
为保证播种机适宜的压实力和稳定的播种深度,提高种子出苗品质,促进后期生长发育,针对现有下压力测量方式灵敏度低、且缺少快速有效精准控制模型的问题,提出一种基于气囊压力和仿形四连杆倾角的播种下压力控制方法。采用一阶低通滤波的轴销传感器下压力监测方式,设计了气动式下压力监控系统,包括气压驱动装置、倾角传感器、数据采集控制卡及上位机控制软件等,轴销传感器和倾角传感器分别实时测量限深轮对地下压力和仿形四连杆倾角,并反馈给上位机,经过模型计算后控制数据采集控制卡发送信号调节气压驱动装置,保证限深轮对地下压力在设定范围内。室内建模和响应测试结果表明,在不同气囊压力和四连杆倾角设置下,建立的播种下压力控制模型校正决定系数为0. 974 3,均方根误差为49. 41 N,试验验证模型预测均方根误差为39. 51 N,对播种下压力具有较好的控制准确性;在0. 1～0. 6 MPa压力设定下,气囊充气阶跃响应平均超调量3. 83%,平均稳态误差0. 005 2 MPa,平均调节时间0. 42 s,满足作业需求。田间播种深度控制性能试验结果表明,在6～10 km/h作业速度范围内,气动式下压力控制系统对播种深度具有稳定可靠的控制性能,系统播种深度合格率不小于98. 91%,特别是在10 km/h高速作业时,播种深度标准差为3. 46 mm,变异系数为6. 97%,显著优于被动弹簧式下压力调节方式。
An adequate and consistent depth positioning of seeds is vital for uniform crop germination to achieve the optimum yield of agricultural crops. However,the downforce variations from the row units will affect the stability of sowing depth because of the irregular and inconsistent soil resistance of the seedbed.Therefore,controlling the seeding downforce to compensate for changes in soil resistance can improve seeding quality. At present,most of the downforce control methods are driven by hydraulic pressure,which requires a high level for the tractor hydraulic system. In addition,previous studies have found that the existing downforce detection methods have problems of low sensitivity and lack of fast and precise control model,which can not achieve real-time accurate downforce control. To solve the problems,a new downforce control method based on the air-spring pressure and the four-link angle was proposed,and a corresponding pneumatic downforce control system was designed. The system consisted of pneumatic driving device,tilt sensor for profiling mechanism,pressure sensor for air-spring,downforce sensor for gauge-wheel,date acquisition and control module,and an upper computer. The pneumatic driving device,which mainly included air-spring,electric-gas proportional valve,air pump,gas tank and oil separation filter,was used to provide the necessary downforce on the profiling mechanism to ensure the optimum and consistency of sowing depth. The downforce sensor and tilt sensor were applied to generate downforce and the four-link angle signals in real time. After first-order low-pass filtering and model calculation by the upper computer,these actual downforce was displayed on the interface programmed by LabVIEW and the control signals were sent to the electrical-gas proportional valve through the date acquisition and control module based on RS485 communication. A modeling experiment was conducted to establish the relationship between the sensor values and the actual downforce under different air-spring pressures and four-link angles. Regression analysis showed that the model fitted the best,being 0. 974 3 in adjusted determination coefficient( R(Adj)~2_) and 49. 41 N in root mean square error( RMSE). The verification test showed that the predicted root mean square error( PRMSE) was 39. 51 N,which showed that the model had better control accuracy for downforce. Further,an air-spring response test and a field test were carried out respectively to test system control performance. The results showed that the airspring inflation step response average overshoot was 3. 83%, the average steady state error was 0. 005 2 MPa,and the average adjustment time was 0. 42 s when the pressure was set in the range of0. 1 ～ 0. 6 MPa. The field tests indicated that the system had stable and reliable control performance for sowing depth in the speed range of 6 ～ 10 km/h. Within the industry standard error range of 10 mm,the qualified rate of sowing depth of the system was not less than 98. 91%. Especially when the speed of the planter was over 10 km/h,the standard deviation( SD) of sowing depth was 3. 46 mm and the coefficient of variation( CV) was 6. 97%,which was significantly better than the passive downforce control system with the SD of 6. 70 mm and the CV of 13. 07% respectively.
An adequate and consistent depth positioning of seeds is vital for uniform crop germination to achieve the optimum yield of agricultural crops. However,the downforce variations from the row units will affect the stability of sowing depth because of the irregular and inconsistent soil resistance of the seedbed.Therefore,controlling the seeding downforce to compensate for changes in soil resistance can improve seeding quality. At present,most of the downforce control methods are driven by hydraulic pressure,which requires a high level for the tractor hydraulic system. In addition,previous studies have found that the existing downforce detection methods have problems of low sensitivity and lack of fast and precise control model,which can not achieve real-time accurate downforce control. To solve the problems,a new downforce control method based on the air-spring pressure and the four-link angle was proposed,and a corresponding pneumatic downforce control system was designed. The system consisted of pneumatic driving device,tilt sensor for profiling mechanism,pressure sensor for air-spring,downforce sensor for gauge-wheel,date acquisition and control module,and an upper computer. The pneumatic driving device,which mainly included air-spring,electric-gas proportional valve,air pump,gas tank and oil separation filter,was used to provide the necessary downforce on the profiling mechanism to ensure the optimum and consistency of sowing depth. The downforce sensor and tilt sensor were applied to generate downforce and the four-link angle signals in real time. After first-order low-pass filtering and model calculation by the upper computer,these actual downforce was displayed on the interface programmed by LabVIEW and the control signals were sent to the electrical-gas proportional valve through the date acquisition and control module based on RS485 communication. A modeling experiment was conducted to establish the relationship between the sensor values and the actual downforce under different air-spring pressures and four-link angles. Regression analysis showed that the model fitted the best,being 0. 974 3 in adjusted determination coefficient( R(Adj)~2_) and 49. 41 N in root mean square error( RMSE). The verification test showed that the predicted root mean square error( PRMSE) was 39. 51 N,which showed that the model had better control accuracy for downforce. Further,an air-spring response test and a field test were carried out respectively to test system control performance. The results showed that the airspring inflation step response average overshoot was 3. 83%, the average steady state error was 0. 005 2 MPa,and the average adjustment time was 0. 42 s when the pressure was set in the range of0. 1 ～ 0. 6 MPa. The field tests indicated that the system had stable and reliable control performance for sowing depth in the speed range of 6 ～ 10 km/h. Within the industry standard error range of 10 mm,the qualified rate of sowing depth of the system was not less than 98. 91%. Especially when the speed of the planter was over 10 km/h,the standard deviation( SD) of sowing depth was 3. 46 mm and the coefficient of variation( CV) was 6. 97%,which was significantly better than the passive downforce control system with the SD of 6. 70 mm and the CV of 13. 07% respectively.
引文
[1]杨丽,颜丙新,张东兴,等.玉米精密播种技术研究进展[J/OL].农业机械学报,2016,47(11):38-48.YANG Li,YAN Bingxin,ZHANG Dongxing,et al. Research progress on precision planting technology of maize[J/OL].Transactions of the Chinese Society for Agricultural Machinery,2016,47(11):38-48. http:∥www. j-csam. org/jcsam/ch/reader/view_abstract. aspx? flag=1&file_no=20161106&journal_id=jcsam. DOI:10. 6041/j. issn. 1000-1298. 2016. 11.006.(in Chinese)
[2] GUPTA S C,SWAN J B,SCHNEIDER E C. Planting depth and tillage interactions on corn emergence[J]. Soil Science Society of America Journal,1988,52(4):1122-1127.
[3] BERTI M T,JOHNSON B L,HENSON R A. Seeding depth and soil packing affect pure live seed emergence of cuphea[J].Industrial Crops&Products,2008,27(3):272-278.
[4]张瑞.一年两熟地区麦茬地玉米免耕播种播深控制机构的研究[D].北京:中国农业大学,2016.ZHANG Rui. Study on precision depth-control mechanism of corn no-till planter in double-cropping area[D]. Beijing:China Agricultural University,2016.(in Chinese)
[5]曹慧英,史建国,朱昆仑,等.播种深度对夏玉米冠层结构及光合特性的影响[J].玉米科学,2016,24(1):102-109.CAO Huiying,SHI Jianguo,ZHU Kunlun,et al. Effects of sowing depth on canopy structure and photosynthetic characteristics of summer maize[J]. Journal of Maize Sciences,2016,24(1):102-109.(in Chinese)
[6]曹慧英,王丁波,史建国,等.播种深度对夏玉米幼苗性状和根系特性的影响[J].应用生态学报,2015,26(8):2397-2404.CAO Huiying,WANG Dingbo,SHI Jianguo,et al. Effects of sowing depth on seedling traits and root characteristics of summer maize[J]. Chinese Journal of Applied Ecology,2015,26(8):2397-2404.(in Chinese)
[7] SáNCHEZ-GIRóN V,RAMíREZ J J,LITAGO J J,et al. Effect of soil compaction and water content on the resulting forces acting on three seed drill furrow openers[J]. Soil&Tillage Research,2005,81(1):25-37.
[8] VOORHEES W B,EVANS S D,WARNES D D. Effect of preplant wheel traffic on soil compaction,water use,and growth of spring wheat[J]. Soil Science Society of America,1985,49(1):215-220.
[9] HANNA H M,STEWARD B L,ALDINGER L. Soil loading effects of planter depth-gauge wheels on early corn growth[J].Applied Engineering in Agriculture,2010,26(4):551-556.
[10] BOSHOFF B V D. Automatic depth control for seed planter based on soil conductance sensing[D]. Raleigh:North Carolina State University,1970.
[11] JR J E M. Interactive planter depth control and pneumatic downpressure system[J]. Transactions of the ASAE,1988,31(1):14-18.
[12]苑严伟,白慧娟,方宪法,等.玉米播种与测控技术研究进展[J/OL].农业机械学报,2018,49(9):1-18.YUAN Yanwei,BAI Huijuan,FANG Xianfa,et al. Research progress on maize seeding and its measurement and control technology[J/OL]. Transactions of the Chinese Society for Agricultural Machinery,2018,49(9):1-18. http:∥www. jcsam. org/jcsam/ch/reader/view_abstract. aspx? flag=1&file_no=20180901&journal_id=jcsam. DOI:10. 6041/j. issn.1000-1298. 2018. 09. 001.(in Chinese)
[13]牛金亮,林静,邢作常,等.免耕播种机液压式加载仿形深度控制系统设计[J].农机化研究,2013,35(12):101-104.NIU Jinliang,LIN Jing,XING Zuochang,et al. Design on sowing depth control system loaded by hydraulic pressure for no-till planter[J]. Journal of Agricultural Mechanization Research,2013,35(12):101-104.(in Chinese)
[14]赵金辉,刘立晶,杨学军,等.播种机开沟深度控制系统的设计与室内试验[J].农业工程学报,2015,31(6):35-41.ZHAO Jinhui,LIU Lijing,YANG Xuejun,et al. Design and laboratory test of control system for depth of furrow opening[J].Transactions of the CSAE,2015,31(6):35-41.(in Chinese)
[15]陈蒋,王淼森,赵明,等.玉米播种机电液播深调节装置运动仿真与优化[J].农机化研究,2017,39(10):128-132.CHEN Jiang,WANG Miaosen,ZHAO Ming,et al. Motion simulation and optimization design of electro-hydraulic sowing depth adjusting device for corn seeder[J]. Journal of Agricultural Mechanization Research,2017,39(10):128-132.(in Chinese)
[16] NIELSEN S K,MUNKHOLM L J,LAMANDéM,et al. Seed drill instrumentation for spatial coulter depth measurements[J]. Computers and Electronics in Agriculture,2017,141:207-214.
[17] NIELSEN S K,MUNKHOLM L J,LAMANDéM,et al. Seed drill depth control system for precision seeding[J]. Computers and Electronics in Agriculture,2018,144:174-180.
[18]李玉环,孟鹏祥,耿端阳,等.玉米播种深度智能调控系统研究[J/OL].农业机械学报,2016,47(增刊):62-68.LI Yuhuan,MENG Pengxiang,GENG Duanyang,et al. Intelligent system for adjusting and controlling corn seeding depth[J/OL]. Transactions of the Chinese Society for Agricultural Machinery,2016,47(Supp.):62-68. http:∥www. j-csam. org/jcsam/ch/reader/view_abstract. aspx? flag=1&file_no=2016s010&journal_id=jcsam. DOI:10. 6041/j. issn. 1000-1298.2016. S0. 010.(in Chinese)
[19]黄东岩,朱龙图,贾洪雷,等.基于压电薄膜的免耕播种机播种深度控制系统[J/OL].农业机械学报,2015,46(4):1-8.HUANG Dongyan,ZHU Longtu,JIA Honglei,et al. Automatic control system of seeding depth based on piezoelectric film for no-till planter[J/OL]. Transactions of the Chinese Society for Agricultural Machinery,2015,46(4):1-8. http:∥www. jcsam. org/jcsam/ch/reader/view_abstract. aspx? flag=1&file_no=20150401&journal_id=jcsam. DOI:10. 6041/j. issn.1000-1298. 2015. 04. 001.(in Chinese)
[20]闫荆,朱龙图,于婷婷,等.免耕播种机播种深度实时监测系统[J].农机化研究,2016,38(9):214-218.YAN Jing,ZHU Longtu,YU Tingting,et al. Seeding depth real-time monitoring system for a no-till planter[J]. Journal of Agricultural Mechanization Research,2016,38(9):214-218.(in Chinese)
[21]付卫强,董建军,梅鹤波,等.玉米播种单体下压力控制系统设计与试验[J/OL].农业机械学报,2018,49(6):68-77.FU Weiqiang,DONG Jianjun,MEI Hebo,et al. Design and test of maize seeding unit downforce control system[J/OL].Transactions of the Chinese Society for Agricultural Machinery,2018,49(6):68-77. http:∥www. j-csam. org/jcsam/ch/reader/view_abstract. aspx? flag=1&file_no=20180608&journal_id=jcsam. DOI:10. 6041/j. issn. 1000-1298. 2018. 06.008.(in Chinese)
[22] Precision Planting Inc. Delta Force operators guide-gen3[EB/OL].(2018-03-01)[2018-10-28]. https:∥cloud.precisionplanting. com/pubs/? view=1xA3Q9ceKbJjmJBKNJVinwQaeXw3Q3Fbn.
[23] PONCET A M,FULTON J P,MCDONALD T P,et al. Effect of heterogeneous field conditions on corn seeding depth accuracy and uniformity[J]. Applied Engineering in Agriculture,2018,34(5):819-830.
[24]付卫强,董建军,丛岳,等.基于玉米播深控制的农田地形模拟系统设计与试验[J/OL].农业机械学报,2017,48(增刊):58-65.FU Weiqiang,DONG Jianjun,CONG Yue,et al. Design and test of farmland-terrain simulation system for corn sowing depth control[J/OL]. Transactions of the Chinese Society for Agricultural Machinery,2017,48(Supp.):58-65. http:∥www. jcsam. org/jcsam/ch/reader/view_abstract. aspx? flag=1&file_no=2017s010&journal_id=jcsam. DOI:10. 6041/j. issn.1000-1298. 2017. S0. 010.(in Chinese)
[2] GUPTA S C,SWAN J B,SCHNEIDER E C. Planting depth and tillage interactions on corn emergence[J]. Soil Science Society of America Journal,1988,52(4):1122-1127.
[3] BERTI M T,JOHNSON B L,HENSON R A. Seeding depth and soil packing affect pure live seed emergence of cuphea[J].Industrial Crops&Products,2008,27(3):272-278.
[4]张瑞.一年两熟地区麦茬地玉米免耕播种播深控制机构的研究[D].北京:中国农业大学,2016.ZHANG Rui. Study on precision depth-control mechanism of corn no-till planter in double-cropping area[D]. Beijing:China Agricultural University,2016.(in Chinese)
[5]曹慧英,史建国,朱昆仑,等.播种深度对夏玉米冠层结构及光合特性的影响[J].玉米科学,2016,24(1):102-109.CAO Huiying,SHI Jianguo,ZHU Kunlun,et al. Effects of sowing depth on canopy structure and photosynthetic characteristics of summer maize[J]. Journal of Maize Sciences,2016,24(1):102-109.(in Chinese)
[6]曹慧英,王丁波,史建国,等.播种深度对夏玉米幼苗性状和根系特性的影响[J].应用生态学报,2015,26(8):2397-2404.CAO Huiying,WANG Dingbo,SHI Jianguo,et al. Effects of sowing depth on seedling traits and root characteristics of summer maize[J]. Chinese Journal of Applied Ecology,2015,26(8):2397-2404.(in Chinese)
[7] SáNCHEZ-GIRóN V,RAMíREZ J J,LITAGO J J,et al. Effect of soil compaction and water content on the resulting forces acting on three seed drill furrow openers[J]. Soil&Tillage Research,2005,81(1):25-37.
[8] VOORHEES W B,EVANS S D,WARNES D D. Effect of preplant wheel traffic on soil compaction,water use,and growth of spring wheat[J]. Soil Science Society of America,1985,49(1):215-220.
[9] HANNA H M,STEWARD B L,ALDINGER L. Soil loading effects of planter depth-gauge wheels on early corn growth[J].Applied Engineering in Agriculture,2010,26(4):551-556.
[10] BOSHOFF B V D. Automatic depth control for seed planter based on soil conductance sensing[D]. Raleigh:North Carolina State University,1970.
[11] JR J E M. Interactive planter depth control and pneumatic downpressure system[J]. Transactions of the ASAE,1988,31(1):14-18.
[12]苑严伟,白慧娟,方宪法,等.玉米播种与测控技术研究进展[J/OL].农业机械学报,2018,49(9):1-18.YUAN Yanwei,BAI Huijuan,FANG Xianfa,et al. Research progress on maize seeding and its measurement and control technology[J/OL]. Transactions of the Chinese Society for Agricultural Machinery,2018,49(9):1-18. http:∥www. jcsam. org/jcsam/ch/reader/view_abstract. aspx? flag=1&file_no=20180901&journal_id=jcsam. DOI:10. 6041/j. issn.1000-1298. 2018. 09. 001.(in Chinese)
[13]牛金亮,林静,邢作常,等.免耕播种机液压式加载仿形深度控制系统设计[J].农机化研究,2013,35(12):101-104.NIU Jinliang,LIN Jing,XING Zuochang,et al. Design on sowing depth control system loaded by hydraulic pressure for no-till planter[J]. Journal of Agricultural Mechanization Research,2013,35(12):101-104.(in Chinese)
[14]赵金辉,刘立晶,杨学军,等.播种机开沟深度控制系统的设计与室内试验[J].农业工程学报,2015,31(6):35-41.ZHAO Jinhui,LIU Lijing,YANG Xuejun,et al. Design and laboratory test of control system for depth of furrow opening[J].Transactions of the CSAE,2015,31(6):35-41.(in Chinese)
[15]陈蒋,王淼森,赵明,等.玉米播种机电液播深调节装置运动仿真与优化[J].农机化研究,2017,39(10):128-132.CHEN Jiang,WANG Miaosen,ZHAO Ming,et al. Motion simulation and optimization design of electro-hydraulic sowing depth adjusting device for corn seeder[J]. Journal of Agricultural Mechanization Research,2017,39(10):128-132.(in Chinese)
[16] NIELSEN S K,MUNKHOLM L J,LAMANDéM,et al. Seed drill instrumentation for spatial coulter depth measurements[J]. Computers and Electronics in Agriculture,2017,141:207-214.
[17] NIELSEN S K,MUNKHOLM L J,LAMANDéM,et al. Seed drill depth control system for precision seeding[J]. Computers and Electronics in Agriculture,2018,144:174-180.
[18]李玉环,孟鹏祥,耿端阳,等.玉米播种深度智能调控系统研究[J/OL].农业机械学报,2016,47(增刊):62-68.LI Yuhuan,MENG Pengxiang,GENG Duanyang,et al. Intelligent system for adjusting and controlling corn seeding depth[J/OL]. Transactions of the Chinese Society for Agricultural Machinery,2016,47(Supp.):62-68. http:∥www. j-csam. org/jcsam/ch/reader/view_abstract. aspx? flag=1&file_no=2016s010&journal_id=jcsam. DOI:10. 6041/j. issn. 1000-1298.2016. S0. 010.(in Chinese)
[19]黄东岩,朱龙图,贾洪雷,等.基于压电薄膜的免耕播种机播种深度控制系统[J/OL].农业机械学报,2015,46(4):1-8.HUANG Dongyan,ZHU Longtu,JIA Honglei,et al. Automatic control system of seeding depth based on piezoelectric film for no-till planter[J/OL]. Transactions of the Chinese Society for Agricultural Machinery,2015,46(4):1-8. http:∥www. jcsam. org/jcsam/ch/reader/view_abstract. aspx? flag=1&file_no=20150401&journal_id=jcsam. DOI:10. 6041/j. issn.1000-1298. 2015. 04. 001.(in Chinese)
[20]闫荆,朱龙图,于婷婷,等.免耕播种机播种深度实时监测系统[J].农机化研究,2016,38(9):214-218.YAN Jing,ZHU Longtu,YU Tingting,et al. Seeding depth real-time monitoring system for a no-till planter[J]. Journal of Agricultural Mechanization Research,2016,38(9):214-218.(in Chinese)
[21]付卫强,董建军,梅鹤波,等.玉米播种单体下压力控制系统设计与试验[J/OL].农业机械学报,2018,49(6):68-77.FU Weiqiang,DONG Jianjun,MEI Hebo,et al. Design and test of maize seeding unit downforce control system[J/OL].Transactions of the Chinese Society for Agricultural Machinery,2018,49(6):68-77. http:∥www. j-csam. org/jcsam/ch/reader/view_abstract. aspx? flag=1&file_no=20180608&journal_id=jcsam. DOI:10. 6041/j. issn. 1000-1298. 2018. 06.008.(in Chinese)
[22] Precision Planting Inc. Delta Force operators guide-gen3[EB/OL].(2018-03-01)[2018-10-28]. https:∥cloud.precisionplanting. com/pubs/? view=1xA3Q9ceKbJjmJBKNJVinwQaeXw3Q3Fbn.
[23] PONCET A M,FULTON J P,MCDONALD T P,et al. Effect of heterogeneous field conditions on corn seeding depth accuracy and uniformity[J]. Applied Engineering in Agriculture,2018,34(5):819-830.
[24]付卫强,董建军,丛岳,等.基于玉米播深控制的农田地形模拟系统设计与试验[J/OL].农业机械学报,2017,48(增刊):58-65.FU Weiqiang,DONG Jianjun,CONG Yue,et al. Design and test of farmland-terrain simulation system for corn sowing depth control[J/OL]. Transactions of the Chinese Society for Agricultural Machinery,2017,48(Supp.):58-65. http:∥www. jcsam. org/jcsam/ch/reader/view_abstract. aspx? flag=1&file_no=2017s010&journal_id=jcsam. DOI:10. 6041/j. issn.1000-1298. 2017. S0. 010.(in Chinese)