玉米免耕播种机精确播种关键技术研究

发布时间：2018-07-24 16:31

【摘要】：我国东北黑土区是世界三大黑土区之一,黑土的自然肥力高,适合农业生产,是我国最重要的粮食生产基地。传统农业生产以精耕细作模式为主,农机具多次进地作业,对土壤扰动频繁;耕地每年有近7个月的时间处于裸露休闲状态,风蚀水蚀现象严重;过量施用农药和化肥导致土壤板结。因此,预防东北黑土区水土流失,提高土壤肥力对保障国家粮食安全,改善生态环境,以及实现农业可持续发展具有重要意义。保护性耕作技术具有蓄水保墒、节本增效、提高土壤有机质含量、减少土壤风蚀水蚀等优点,经过多年的研究和发展已在全世界范围内大面积推广应用。保护性耕作技术的核心环节是作物残茬覆盖和免耕播种作业,精密排种器作为免耕播种机的关键部件,其在免耕播种作业时性能的优劣决定着保护性耕作的效果。与普通播种机相比,免耕播种机的作业环境更恶劣,地表不平度和作物秸秆、残茬都会引起播种机振动,尤其在高速精密播种时,振动对精密排种器的影响更加显著。因此,本文重点研究秸秆覆盖条件下播种机振动对排种器工作性能的影响规律,进而设计相应的减振工作部件减小免耕播种机振动,提高播种质量。(1)通过对比试验,测试指夹式排种器在链传动和电机驱动两种情况下,所受到的振动情况,并比较两者的播种合格指数、重播指数和漏播指数。通过土槽测试的方法得出播种单体作业时的振动特性,包括振动加速度和频率。根据试验数据,设计了一种振动测试试验台,可模拟免耕播种机田间作业工况,并对振动条件下指夹式排种器的作业性能和影响因素进行了台架试验。试验结果表明,排种器振动频率与振动幅值均对播种合格指数与漏播指数有显著影响,排种器振动频率对播种合格指数的影响较排种器振动幅值对播种合格指数影响显著;排种器振动频率对播种漏播指数的影响较排种器振动幅值对播种漏播指数的影响显著。台架试验可为后续减振装置设计提供参考。(2)提出一种免耕播种机播种单体减振自动控制方法,并设计播种单体减振自动控制系统。应用PVDF压电薄膜制作免耕播种机限深轮胎面形变传感器,实时监测播种单体的对地压力,间接计算出开沟器的实际开沟深度,当与目标深度不一致时,系统通过控制空气弹簧增加或减小播种单体对地压力,达到减小振动、控制播深、提高播种质量的目标。田间试验结果表明,播种单体减振自动控制系统在播种机作业速度为5~8 km/h时,播深合格率达到91%以上,其中在作业速度为7 km/h时播深合格率最高;振动加速度平均减小30%以上,其中在作业速度为7 km/h时减小幅度最大;振动频率平均减小24%以上,其中在作业速度为6 km/h时减小幅度最大;振幅平均减小30%以上,其中在作业速度为7 km/h时减小幅度最大。可以看出,在高速作业时播种单体减振自动控制系统的性能明显优于被动式仿形机构。(3)设计一种免耕播种机秸秆切割防堵装置,采取主被动结合的切割方式和组合刀片式结构,每个防堵装置在3个平面内安装切割刀具。其中两侧的刀具采取被动旋转作业,位于中间的刀具采取主动旋转作业,作业时可对秸秆(根茬)进行有支撑切割作业,提高切断率、降低功耗。田间试验结果表明:各影响因子对秸秆(根茬)切断率的显著性顺序从大到小依次为主动刀盘转速、刀片回转半径、机具前进速度;对单把刀片功率消耗的显著性顺序从大到小依次为主动刀盘转速、机具前进速度、刀片回转半径。在保证秸秆(根茬)切断率为95%以上的前提下,由Design-Expert软件预测出秸秆(根茬)切断率与单把刀片功率消耗的最佳因素组合为前进速度2.1 m/s、主动刀盘转速120 r/min、刀片回转半径200mm。根据最佳参数进行验证试验,结果表明由最佳工作参数组合得到的秸秆(根茬)切断率平均值为95.3%,单把刀片功率消耗平均值为145.2 W。(4)研制一种免耕播种机远程播种性能监测系统,包括播种监视子系统、排种检测子系统、GPS定位子系统和远程服务器等四部分。以GPS接收器作为漏播、重播位置采集器,GPRS DTU模块作为远程传输工具,STM32单片机为核心处理器、PVDF压电传感器为监测元件。该系统能够实时准确地监测播种机的各项性能指标,并将播种质量信息数据的远程传输,远程服务器程序实现数据接收、存储、查询、统计、分析、处理和报警等功能。田间试验结果表明,远程播种性能监测系统性能稳定、可靠,能够有效地监测播种机的播种质量,对播种量检测精度为97.4%,漏播检测精度为96.1%,重播检测精度为95.9%,并且实现了播种质量信息位置的精确定位。(5)对2BMZ-4型宽窄行免耕播种机进行改进设计,并进行整机田间试验,考察免耕播种机播种单体减振自动控制系统、秸秆切割防堵装置和远程播种监测系统的实际工作效果。试验结果表明,2BMZ-4型宽窄行免耕播种机具有较好的作业性能。上述工作为玉米免耕播种机精确播种关键技术的研究提供了技术参考,具有实际应用价值。
[Abstract]:The black soil area of Northeast China is one of the three largest black soil areas in the world. The natural fertility of the black soil is high and is suitable for agricultural production. It is the most important grain production base in our country. The traditional agricultural production is mainly based on the intensive farming model, the agricultural machinery is working many times and the soil is disturbed frequently, and the arable land has nearly 7 months in the nude leisure state and wind erosion. Water erosion is serious; excessive application of pesticide and chemical fertilizer leads to soil slate. Therefore, it is of great significance to prevent soil erosion in the northeast black soil area and improve soil fertility to ensure national food safety, improve the ecological environment, and realize the sustainable development of agriculture. The core of conservation tillage technology is crop residue covering and no tillage sowing, and precision seed metering device is the key component of no tillage planter, and its performance in no tillage sowing operation is determined by the content of soil erosion and water erosion for many years. The effect of protective tillage. Compared with the ordinary seeder, the working environment of the no tillage planter is worse, the surface roughness and the crop straw, the stubble will cause the vibration of the planter, especially in the high speed precision sowing, the influence of vibration on the precision seeder is more obvious. Therefore, this paper focuses on the vibration of the planter under straw mulching. In order to reduce the vibration of no tillage planter and improve the sowing quality, the corresponding damping working parts are designed to improve the sowing quality. (1) through the contrast test, the vibration conditions of the finger pinch type seed metering device under the two conditions of chain drive and motor drive are tested, and the sowing index, the replay index and the leakage index are compared with those of the two. The vibration characteristics, including vibration acceleration and frequency, were obtained by the method of soil trough testing, including vibration acceleration and frequency. Based on the test data, a vibration test rig was designed to simulate the working conditions of no tillage planter in the field, and a bench test was carried out on the work performance and influence factors of the finger pinch seeder under vibration conditions. The results show that both the vibration frequency and the amplitude of the seed metering device have significant influence on the sowing index and the leakage index. The vibration frequency of the seed metering device has a significant influence on the sowing index and the vibration amplitude of the seed metering device on the sowing index. The vibration frequency of the seed seeder has a better effect on sowing index than the sowing device vibration amplitude. The influence of the leakage index is significant. The bench test can provide reference for the design of subsequent vibration damping device. (2) an automatic control method of the sowing monomer for no tillage seeder is proposed, and the automatic control system of the sowing monomer is designed. The PVDF piezoelectric film is used to make the deep wheel tread deformation sensor of the no tillage planter to monitor the sowing monomer in real time. For the ground pressure, the actual opening depth of the trench is calculated indirectly. When the target depth is not consistent with the target depth, the system can increase or reduce the ground pressure by controlling the air spring to reduce the vibration, control the sowing depth and improve the sowing quality. The field test results show that the automatic control system of the sowing monomer vibration damping is done in the sowing machine. When the speed is 5~8 km/h, the qualified rate of sowing depth is above 91%, of which the sowing depth is the highest when the operation speed is 7 km/h, and the vibration acceleration is reduced by more than 30%, of which the maximum decrease of the vibration frequency is 7 km/h, and the vibration frequency decreases more than 24%, of which the maximum amplitude decreases when the working speed is 6 km/h; the amplitude decreases averagely. It is more than 30% small, which reduces the maximum amplitude when the operation speed is 7 km/h. It can be seen that the performance of the automatic control system of the sowing monomer in the high speed operation is obviously superior to the passive copying mechanism. (3) a non tillage seeder straw cutting and blocking device is designed, the cutting mode of the main passive combination and the combined blade structure are adopted. The cutters in 3 planes are installed in the anti blocking device. The cutting tool on both sides takes the passive rotation operation, the tool in the middle takes the active rotation operation, and the straw (root stubble) can be cut and cut during the operation to improve the cutting rate and reduce the power consumption. The field test results show that the cutting rate of the straw (root) by the influence factors is obvious. The order from large to small is the rotational speed of the active cutter, the radius of the blade and the speed of the machine. The significant order of the power consumption of the single blade from large to small is the rotating speed of the active cutter, the speed of the machine tool and the radius of the blade, and the Design-Expert software is predicted by the Design-Expert software on the premise that the cutting rate of the straw is above the cutting rate of more than 95%. The best combination of the cutting rate of straw (root stubble) and the power consumption of single blade was 2.1 m/s, 120 r/min of the rotating speed of the active cutter, and the rotary radius 200mm. of the blade was tested according to the optimum parameters. The results showed that the average cutting rate of straw (root stubble) was 95.3%, and the power consumption of the blade was consumed by the combination of the best working parameters. The average value is 145.2 W. (4) to develop a remote seeding performance monitoring system for no tillage seeder, including seeding monitoring subsystem, seed metering subsystem, GPS positioning subsystem and remote server and other four parts. The GPS receiver is used as a leak, replay location collector, GPRS DTU block as a remote transmission tool and STM32 MCU as the core processing. The PVDF piezoelectric sensor is a monitoring element. The system can monitor the performance index of the seeder in real time and accurately, and transmit the data of the sowing quality information, the remote server program realizes the functions of data receiving, storage, inquiry, statistics, analysis, processing and alarm. The field test results show that the remote seeding performance monitoring system is used. The system has a stable and reliable performance. It can effectively monitor the sowing quality of the seeder. The precision of the sowing quantity is 97.4%, the leakage detection precision is 96.1%, the precision of the replay detection is 95.9%, and the accurate location of the sowing quality information is realized. (5) the improved design of the 2BMZ-4 type wide narrow row non tillage seeder is carried out and the field experiment is carried out. The experimental results show that the 2BMZ-4 type wide narrow row no tillage seeder has good working performance. The above work provides the technical reference for the research of the key technology for the precision seeding of the maize no tillage seeder. The examination is of practical application value.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S223.2

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