温室钵苗移栽机的优化设计及移栽过程力学分析

发布时间：2018-05-30 12:12

本文选题：钵苗移栽机 + 末端执行器　；参考：《浙江大学》2017年博士论文

【摘要】：工厂化育苗技术因具有生产效率高、成本低、可连续生产等诸多优点,已在我国得到了普遍推广和应用。随着育苗技术的发展,温室自动化移栽设备的需求也越来越大。针对国内温室钵苗移栽装备作业效率低和可靠性差的问题,以浙江大学原有移栽设备为基础,本文首先进行了补苗移栽策略的改进、苗盘分送装置的设计、机械间苗装置的设计、末端执行器的优化设计及测试等研究,从硬件系统方面提高移栽系统的可靠性和效率,接着基于设计的末端执行器搭建实时测力系统,分析基质含水率、基质体积配比、单孔基质量等育苗农艺参数对移栽作业过程中拉拔力和夹紧力的影响,探讨夹紧力和拉拔力与移栽效果之间的关系,为末端执行器的安装调试提供理论指导,进一步提高移栽作业的可靠性,最后采用蚁群算法对末端执行器补苗移栽作业的路径进行规划,通过缩短补苗路径,在不增加硬件成本的前提下进一步提高移栽作业的效率。主要研究内容和结论如下:(1)提出了新的补苗策略,并且设计了一套苗盘分送装置及控制系统,可以根据穴盘内缺苗数的多少对穴盘进行归类,减少了补苗作业的工作量,提高了补苗作业的效率。设计了一种穴盘机械分隔装置及控制系统,装置的列分隔组件的核心为一组卷曲布帘,解决了原有装置伤苗的问题,增加了设备的可靠性。(2)设计了一种单气缸驱动的插拔夹取式末端执行器,不仅保证了钵苗的主动分离,还可以在气缸的一个推程内连续完成插入并夹紧育苗基质的动作。根据指针尖点的运动轨迹,基于编写的VB程序对末端执行器的关键结构尺寸进行了综合确定。移栽测试结果显示:设计的末端执行器对不同育苗农艺条件下Q72穴盘中黄瓜苗的移栽成功率达到100%,基质块的平均损伤率为17%,且损伤程度均较小;对Q72穴盘中番茄、辣椒钵苗的移栽成功率同样达到100%,基质块的严重损伤率分别为2.5%和4.5%;对Q128穴盘中黄瓜苗的移栽成功率也达到100%,基质块的损伤率为23.8%。该末端执行器对育苗农艺、作物品种和穴盘规格都具有较强的适应性,且在保证钵苗基质块完整性方面具有较大的突破。与原有第三代末端执行器相比,该末端执行器的可靠性和效率均有较大提高。(3)基于设计的末端执行器搭建了一套实时测力系统,其核心部件为两个高精度、快速响应的力学传感器,可实时测量移栽过程中的拉拔力和夹紧力。通过力学分析和几何关系分别建立了拉拔力和夹紧力的计算方式,并采用万能试验机对传感器进行了标定。为验证该实时测力系统的有效性,进行了移栽试验并分析夹紧力和拉拔力随育苗基质含水率的变化。试验共得到6个梯度的含水率,且结果表明,拉拔力随含水率的降低先增大后降低,夹紧力随含水率的降低而增大。含水率76%左右时,同试验组内拉拔力的标准偏差较小;含水率74%左右时,同试验组内夹紧力的标准偏差较小。(4)通过三因素三水平的全面交互试验研究3个主要农艺育苗参数(基质含水率、基质体积配比和单孔基质量)对移栽作业过程中夹紧力和拉拔力的影响,并探讨了夹紧力、拉拔力与移栽效果之间的关系。试验中共有9盘钵苗,每盘钵苗被分为3个区域,每个区域为1个试验组,一共27组。每个试验组随机选取10株钵苗进行重复移栽试验。采用多因素方差分析法研究了 3个主要农艺育苗参数对夹紧力和拉拔力影响的显著性。对夹紧力的分析表明,基质含水率、基质体积配比和单孔基质量对夹紧力的影响均十分显著(P0.05),且影响的显著性依次为:基质含水率单孔基质量基质体积配比。3个育苗参数两两之间的交互作用以及3个参数之间的交互作用对夹紧力的影响均十分显著(P0.05)。其中,基质含水率与基质体积配比、基质含水率与单孔基质量之间的交互作用最为显著。对拉拔力的分析表明,基质含水率、基质体积配比和单孔基质量对拉拔力的影响均十分显著(P0.05),且影响的显著性依次为:单孔基质量基质含水率基质体积配比。只有基质体积配比与单孔基质量之间的交互作用对拉拔力有显著影响(P0.05),其余参数之间的交互作用均不显著。进一步分析表明,基质含水率在82.5%-78.5%范围内逐渐下降时,夹紧力和拉拔力的均值呈线性增长。基质体积配比为7:2:1水平时,夹紧力的均值最大;基质体积配比为6:2:2水平时,拉拔力的均值最大。夹紧力均值随着单孔基质量的增加先增大后减小,拉拔力均值随着单孔基质量的增加而增大,但是增大的趋势变缓。结合移栽效果分析发现,移栽效果的好坏并不直接与夹紧力或者拉拔力相关。进一步分析夹紧力与拉拔力的和、差、乘积、比值,发现移栽效果与夹紧力和拉拔力的比值之间存在一定的关系。当夹紧力与拉拔力的比值在5.99～8.67的范围内时,移栽效果相比会更好。该试验结果可以为末端执行器的设计、安装和调节提供指导,提高末端执行器移栽的可靠性和效率。(5)基于蚁群算法实现了末端执行器补苗移栽作业的路径规划。根据输出路径的长度,通过交互试验确定算法的关键参数取值,遗传算法中取pc=0.8、pm = 0.3,蚁群算法中取α=1,β=20,ρ=0.]。与遗传算法相比,蚁群算法输出结果的收敛速度较慢,且波动较大,但蚁群算法第一次迭代运行后的输出结果要远远优于遗传算法。对10种随机的穴盘状态进行路径规划,遗传算法和蚁群算法的平均运行时间分别为0.32 s和0.94 s。相比于传统的CSM(Common Sequence Method,固定顺序扫描法)方法,遗传算法和蚁群算法都可以显著缩短补苗路径的长度。然而遗传算法由于算法本身的局限性,不能处理只有]个空穴的情况。通常情况下,蚁群算法输出结果的标准差要小于遗传算法。待补穴盘中空穴数量和供苗穴盘中健康钵苗的数量之和(p+q)对遗传算法和蚁群算法优化效果的相对优劣影响显著,其和越大,蚁群算法的优势越明显。使用20×10穴盘进行优化效果对比,蚁群算法完成40个空穴的补苗路径比遗传算法的路径短6000.9 mm(33.2%),比传统的CSM方法短13058.4mm(51.9%)。整体比较发现,蚁群算法更适合用于末端执行器补苗移栽作业的路径规划,可在不增加硬件成本的条件下进一步提高设备的作业效率。
[Abstract]:Because of the advantages of high production efficiency, low cost and continuous production, the plant cultivation technology has been widely popularized and applied in China. With the development of the seedling raising technology, the demand for the automatic transplanting equipment of greenhouse is becoming more and more large. The problem of low efficiency and poor reliability of the domestic greenhouse seedling transplanting equipment is Zhejiang big. On the basis of the original transplanting equipment, this paper first carried out the improvement of the strategy of replanting and transplanting, the design of the seedling plate distribution device, the design of the mechanical thinning device, the optimization design and testing of the end effector, and the improvement of the reliability and efficiency of the transplanting system from the hardware system, and then built the real-time measurement based on the designed terminal actuator. The relationship between the clamping force and the pulling force and the effect of the transplanting is discussed. The relationship between the clamping force and the pulling force and the effect of the transplanting is discussed, and the theoretical guidance for the installation and debugging of the terminal actuator is provided, and the reliability of the transplanting operation is further improved. An ant colony algorithm is used to plan the path of the transplant operation of the end effector. By shortening the route of the supplement, the efficiency of the transplanting operation is further improved without increasing the cost of hardware. The main contents and conclusions are as follows: (1) a new strategy is put forward, and a set of seedling disk distribution device and control system are designed. In order to classify the hole disc according to the number of the holes in the hole, it reduces the workload of the remedial work and improves the efficiency of the remedial work. A device and control system are designed. The core of the column dividing component is a set of curled cloth curtains, which solves the problem of the original plant injury and increases the reliability of the equipment. 2) a single cylinder driven plug and fetching end actuator is designed, which not only ensures the active separation of the bowl seedlings, but also can continuously insert and clamp the nursery matrix in a push range of the cylinder. Based on the moving trajectory of the pointer point, the key structure size of the terminal executor is synthesized based on the written VB program. The results of transplanting test showed that the successful rate of transplant success of the designed end actuators to the cucumber seedlings of Q72 acupoints under different cultivation conditions was 100%, the average damage rate of the matrix block was 17%, and the damage degree was small; the successful rate of transplant success of Tomato in Q72 and the serious damage rate of the matrix block was respectively 100%. For 2.5% and 4.5%, the successful rate of transplant success of Cucumber Seedlings in Q128 is 100%. The damage rate of matrix block is 23.8%., the end actuator has strong adaptability to seedling farming, crop variety and point plate specification, and it has a great breakthrough in guaranteeing the integrity of the matrix block. Compared with the original third generation end actuator, The reliability and efficiency of the terminal actuator have been greatly improved. (3) a set of real-time force measuring system is set up based on the design - based terminal actuator. The core component is two high precision and fast response mechanical sensors, which can measure the pulling force and clamping force in the transplanting process in real time. Through the mechanical analysis and the geometric relationship, the pulling force is established respectively. In order to verify the effectiveness of the real time force measuring system, a transplanting test was carried out and the change of the water content of the clamping force and drawing force with the seedling matrix was analyzed to verify the effectiveness of the real time force measuring system. The test results showed that 6 gradient water content was obtained in the test, and the results showed that the drawing force increased with the decrease of water content first. When the water content is about 76%, the standard deviation of drawing force in the test group is smaller when the water content is about 76%. When the water content is about 74%, the standard deviation of the clamping force is smaller in the test group. (4) through the comprehensive interactive test of three factors and three levels, the parameters of the 3 main agronomic seedlings (matrix water content, matrix body) are studied. The influence of product ratio and single hole base mass on the clamping force and pulling force in the process of transplanting, and the relationship between the clamping force, drawing force and the effect of transplanting are discussed. There are 9 plates of bowl seedlings in the experiment. Each bowl is divided into 3 regions, each area is 1 test groups and a total of 27 groups. 10 seedlings of each test group are randomly selected to repeat the shift. The effects of 3 main agronomic parameters on the clamping force and pulling force are studied by the multi factor variance analysis. The analysis of the clamping force shows that the influence of matrix water content, matrix volume ratio and single hole base mass on the clamping force is very significant (P0.05), and the significance of the influence is the matrix water content single hole in turn. The interaction between the base mass matrix volume ratio.3 breeding parameters 22 and the interaction between the 3 parameters and the interaction effect on the clamping force are all very significant (P0.05). Among them, the interaction between matrix water content and matrix volume, the interaction between the matrix water content and the single pore base mass is the most significant. The analysis of drawing force shows that matrix The effect of water content, matrix volume ratio and single hole base mass on drawing force is very significant (P0.05), and the significant effect is the matrix volume ratio of the mass matrix of single hole base mass. Only the interaction between the matrix volume ratio and the mass of single pore base has significant influence on drawing force (P0.05), and the interaction between the other parameters is made. It is not significant for use. Further analysis shows that the mean of clamping force and drawing force increases linearly when the matrix moisture content decreases gradually within the range of 82.5%-78.5%. When the matrix volume ratio is 7:2:1, the mean of the clamping force is the largest. When the matrix volume ratio is 6:2:2 level, the mean of drawing force is the largest. The mean of clamping force is with the base mass of the single hole. The increase first increases and then decreases, and the Rabari mean increases with the increase of the mass of the single hole base, but the increasing trend slows down. It is found that the effect of transplanting is not directly related to the clamping force or drawing force. Further analysis of the effect of the clamping force and drawing force, the difference, the product and the ratio, and the discovery of the effect of transplanting and the clamping force There is a certain relationship between the ratio of pulling force and the drawing force. When the ratio of the clamping force to drawing force is within the range of 5.99 ~ 8.67, the effect of transplanting is better. The result of the experiment can provide guidance for the design, installation and adjustment of the end actuators, and improve the reliability and efficiency of the transplanting of the end effector. (5) the end of the experiment is based on the ant colony algorithm. According to the length of the output path, according to the length of the output path, the key parameters of the algorithm are determined by the interactive experiment. Pc=0.8, PM = 0.3 in the genetic algorithm are taken. The ant colony algorithm takes the alpha =1, beta =20, and P =0.]. as the genetic algorithm, and the ant colony algorithm has a slower convergence rate and a larger fluctuation, but the ant colony algorithm is the first one. The output results after one iteration are far superior to the genetic algorithm. The path planning of 10 random cavern States is carried out. The average running time of the genetic algorithm and the ant colony algorithm is 0.32 s and 0.94 S., respectively, compared to the traditional CSM (Common Sequence Method, fixed sequence scanning) method, and the genetic algorithm and the ant colony algorithm are all obvious. However, due to the limitations of the algorithm itself, the genetic algorithm can not handle only a hole. In general, the standard deviation of the output results of the ant colony algorithm is less than that of the genetic algorithm. The number of holes in the pending hole and the sum of the health bowl seedlings in the supply of the hole discs (p+q) are the genetic algorithm and the ant colony algorithm The relative advantages and disadvantages of the optimization effect are significant, the more obvious it is, the more obvious the advantage of the ant colony algorithm is. Using the 20 x 10 hole disk to make the optimization effect comparison, the ant colony algorithm completes the 40 hole filling path shorter than the genetic algorithm's path is 6000.9 mm (33.2%), and is shorter than the traditional CSM method (51.9%). The overall comparison shows that the ant colony algorithm is more suitable for use. The path planning of the end effector seedling transplant operation can further improve the operation efficiency of the equipment without increasing the cost of hardware.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S223.9

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