Design and Experimental Research on Seedling Pick-Up Mechanism of Planetary Gear Train with Combined Non-circular Gear Transmission

Currently, transplanting mechanisms for dryland plug seedlings in China are mainly semiautomatic and have low efficiency. The rotary seedling pick-up mechanism with a planetary gear train for non-uniform intermittent transmission, and a concave and convex locking arc device, has a large rigid impact. To solve these problems, according to the design requirements for a dryland plug seedling transplanting mechanism, a rotary seedling pick-up mechanism of a planetary gear train with combined non-circular gear transmission of incomplete eccentric circular and noncircular gears was proposed. This has the characteristics of two-times greater fluctuation of the transmission ratio in a cycle, and can achieve a non-uniform continuous drive. Through analysis of the working principle of the seedling pick-up mechanism, its kinematics model was established. The human–computer interaction optimization method and self-developed computer-aided analysis and optimization software were used to obtain a set of parameters that satisfy the operation requirements of the seedling pick-up mechanism. According to the optimized parameters, the structure of the seedling pick-up mechanism was designed, a virtual prototype of the mechanism was created, and a physical prototype was manufactured. A virtual motion simulation of the mechanism was performed, high-speed photographic kinematics tests were conducted, and the kinematic properties of the physical prototype were investigated, whereby the correctness of the theoretical model and the optimized design of the mechanism were verified. Further, laboratory seedling pick-up tests were conducted. The success ratio of seedling pick-up was 93.8% when the seedling pick-up efficiency of the mechanism was 60 plants per minute per row, indicating that the mechanism has a high efficiency and success ratio for seedling pick-up and can be applied to a dryland plug seedling transplanter.

Design of Vegetable Pot Seedling Pick‑up Mechanism with Planetary Gear Train

It has been challenging to design seedling pick-up mechanism based on given key points and trajectories,because it involves dimensional synthesis and rod length optimization.In this paper,the dimensional synthesis of seedling pickup mechanism with planetary gear train was studied based on the data of given key points and the trajectory of the endpoint of seedling pick-up mechanism.Given the positions and orientations requirements of the five key points,the study first conducted a dimensional synthesis of the linkage size and center of rotation.The next steps were to select a reasonable solution and optimize the data values based on the ideal seedling trajectory.The link motion was driven by the planetary gear train of the two-stage gear.Four pitch curves of noncircular gears were obtained by calculating and distributing the transmission ratio according to the data.For the pitch curve with two convex points,the tooth profile design method of incomplete noncircular gear was applied.The seedling pick-up mechanism was tested by a virtual prototype and a physical prototype designed with the obtained parameter values.The results were consistent with the theoretical design requirements,confirming that the mechanism meets the expected requirements for picking seedlings up.This paper presents a new design method of vegetable pot seedling pick-up mechanism for an automatic vegetable transplanter.

Reverse design and tests of vegetable plug seedling pick-up mechanism of planetary gear train with non-circular gears

In the previous research,the seedling pick-up mechanism of the planetary gear train with incomplete eccentric circular gear and non-circular gears for vegetable plug seedlings still has two shortcomings.One is that not enough seedling pick-up depth leads to a low success ratio of seedling pick-up at high rotation speeds,the other is that the smaller seedling pushing angle results in poor seedling pushing effect.Therefore,the reverse design of the seedling pick-up mechanism based on its motion trajectory was carried out.The local trajectory of seedling pick-up and seedling pushing sections was adjusted to obtain the theoretical motion trajectory of the seedling pick-up mechanism.The cubic non-uniform B-spline curve was used to fit the adjusted trajectory.A novel seedling pick-up mechanism of the planetary gear train with non-circular gears was proposed,including three combined non-circular gears,four non-circular gears,one planetary carrier,and two seedling pick-up arms.The reverse design model of the mechanism was established.The analysis and design software of the mechanism was developed to obtain the mechanism parameters meeting design requirements.The virtual prototype of the mechanism was established and its physical prototype was manufactured.Through the virtual motion simulation and high-speed photographic kinematics bench tests of the mechanism,the kinematic model and results of reverse design of the mechanism were verified,with the kinematic performances of the mechanism prototype studied.The seedling pick-up tests of the mechanism were conducted in the laboratory.The success ratios of seedling pick-up were 94.2%,95.6% and 90.2% while the seedling pick-up efficiencies of the mechanism were 60,80 and 100 plants per minute per row,respectively.Besides,the seedling pushing effect was improved mush because of the greater seedling pushing angle.The seedling pick-up mechanism through revise design is of high value to be applied in the practical vegetable plug seedling transplanters.

Design and tests of a rotary plug seedling pick-up mechanism for vegetable automatic transplanter

The rotary plug seedling pick-up mechanism for vegetable automatic transplanter is the technical bottleneck to improve the mechanization level of vegetable planting in China.In order to solve the problems of rotary seedling pick-up mechanism proposed in previous study,such as low success ratio of seedling pick-up at high speed,and interference between the seedling bowl and the end of the other seedling pick-up arm,a novel kind of rotary seedling pick-up mechanism of planetary gear train with combined type gears of incomplete denatured-eccentric-circular and non-circular gears was proposed.Through kinematic analysis of the seedling pick-up mechanism,the kinematics model was established.The computer-aided analysis and optimization software with human-computer interaction method was developed to realize parameters optimization of the seedling pick-up mechanism.Three-dimensional parametric design system of seedling pick-up mechanisms with combined non-circular gear transmission was developed for mechanism virtual simulation to verify the correctness of theoretical model and design results of the mechanism.The physical prototype of the mechanism was manufactured,and high-speed camera kinematics tests of the mechanism were conducted in the laboratory to study its kinematic characteristics.Laboratory seedling pick-up tests were carried out.The mechanism has the success ratio of seedling pick-up 96.3%without interference during seedling transporting when the rotation speed of the mechanism is 50 r/min and the seedling transplanting efficiency is 100 plants/min per row,showing that the novel mechanism has better working performance than the original one and could be applied in vegetable plug seedling transplanter.

Development of single row automatic transplanting device for potted vegetable seedlings

In China,low degree of automation seriously affects the working efficiency and quality in vegetable transplanting.As one of the most important vegetables in China even in the world,tomato was taken as the research object in this study.An automatic single-row transplanting device was designed,based on the statistical analysis of the physical and mechanical properties of tomato seedlings of a typical variety.Based on the technology of mechatronics,the device integrated the functions of transporting seedling tray,automatic seedling extraction and mechanical planting.The kinematics orthogonality solution combined with the dynamic sequence solution method was used to optimize and analyze the kinematic parameters of the automatic seeding mechanism,and the“sickle”trajectory was obtained.According to the position and movement requirement for taking and dropping seedling,the mechanical conditions and the working parameters of key execution parts were obtained by using analytic drawing method to analyze the mechanical condition of seedling collecting mechanism.The transplanting experiment was conducted at room temperature of 25°C,and the age and moisture content of the seedlings were 40 d and 55%,respectively.The results showed that the highest success rate was 92.59%,and the lowest rate of leakage was 23.13%,when the transplanting frequency was 60 plants/min.The lowest success rate was 77.78%,and the highest rate of leakage was 38.75%,when transplanting frequency was 120 plants/min.When the transplanting frequency is between 60-90 plants/min,the device can meet the requirement of high speed transplanting for potted vegetable seedling.

辣椒穴盘苗自动取投苗装置设计与试验

针对现有的半自动辣椒移栽机效率低、劳动强度大的问题,设计一种自动取投苗装置。该装置由夹苗部件、平移机构、垂直移动机构、控制系统和穴盘架等组成。控制系统驱动平移机构和垂直移动机构运动,分别带动夹苗部件和穴盘使其产生联动,实现夹苗部件依次从穴孔中将辣椒苗拔出,然后移动到导苗管上方投苗,完成整个取投苗过程。用72孔穴盘育苗,选取55天苗龄的辣椒穴盘苗为研究对象,对5盘共360株辣椒穴盘苗,以15株/min的移栽速度,进行取投苗试验,试验结果得到:取苗成功率为96.39%,投苗成功率为98.27%,茎叶损伤率为7.79%,满足辣椒穴盘苗移栽的农艺要求,该研究可为自动化移栽机的设计提供参考。

基于DE-SVM的穴盘苗自动取苗机构故障诊断方法

为解决穴盘苗取苗机构早期机械故障识别困难的问题,提高故障诊断的准确率,提出一种基于DE-SVM的穴盘自动苗取苗机构故障诊断方法。首先,采用经验模态分解(Empirical Mode Decomposition,EMD)、变分模态分解(Variational Mode Decomposition,VMD)等预处理方法挖掘潜藏在取苗机构原始振动信号中的故障信息;其次,分别从原始振动信号和预处理信号中提取时域统计特征,再运用距离评估(Distance Evaluation,DE)技术获得表征取苗机构故障的敏感时域统计特征,构建特征向量序列;最后,结合支持向量机(Support Vector Machine,SVM)分类算法对取苗机构运行状况进行识别。室内试验结果表明:此方法可有效区分取苗机构滑道故障、凸轮故障、弹簧故障和正常状况等4种工况,具有运算复杂度低、识别准确率高的优点,可为自动移栽取苗机构工况监测提供一种参考。

茄果类蔬菜自动移栽机夹取式取苗机构的研究进展

茄果类蔬菜种植规模大,育苗移栽环节劳动强度大、效率低。为提高茄果类蔬菜移栽质量和效率,自动移栽机应运而生。夹取式取苗机构是茄果类蔬菜自动移栽机的关键部件,该部件的性能将直接影响移栽钵苗的质量。综述了夹取式(夹茎式和夹钵式两类)取苗机构的研究现状,在总结和分析夹茎式和夹钵式取苗机构的优缺点和工作原理的基础上,分析了制约夹取式取苗机构和茄果类自动移栽机发展的原因,并从提高农机与农艺融合程度;提高控制系统精度,增强对取苗机构材质的相关研究;提高移栽机的自动化、智能化和一体化程度等方面提出了该领域未来的研发重点。

水稻有序抛秧机自动续盘系统的设计与关键结构优化

水稻有序抛秧机续盘作业主要依赖于人工,存在劳动强度较大、人工成本高等问题。基于2ZPY-13A水稻有序抛秧机平台,采用二自由度直角坐标系机械手作为关键执行部件,设计了一种自动续盘系统。运用SolidWorks建立了整体的三维模型,使用Simulation插件对机械手的关键部件取盘架进行了静应力分析和优化,优化后变形量降低54.8%,应力降低40.4%,有效提高了取盘架的作业稳定性和力学性能。

辣椒穴盘苗自动取苗机构运动学分析与试验

针对新疆半自动移栽机人工取苗效率低、强度大、漏苗率及伤苗率高的问题,该文设计了一种辣椒穴盘苗自动取苗机构。分析了该机构的组成及工作原理,建立了其运动学模型,研究了取苗轨迹形成的机理,在确定优化目标的基础上,基于VB开发了取苗机构辅助分析软件,结合Adams运动仿真软件,通过人机交互分析其主要结构参数变化对取苗针端点运动轨迹的影响,优化取苗针端点运动轨迹,获得一组满足辣椒穴盘苗移栽农艺要求的自动取苗机构参数。虚拟样机运动仿真结果表明优化参数可以满足辣椒穴盘苗取苗工作轨迹要求;设计制作了自动取苗试验台,并利用高速摄影技术对取苗机构运动特性进行试验分析,试验结果表明取苗针实际运动轨迹与理论分析结果一致,取苗试验结果如下:取苗成功率为98.6%,基质损伤率为4.2%,投苗成功率为94.2%,满足机械自动取苗的工作要求,验证了取苗机构设计的准确性与合理性。该研究可为辣椒、番茄等作物全自动移栽机自动取苗机构的研发提供参考。

水稻秧盘育秧精密播种流水线软硬秧盘自动叠放装置

设计了一种能实现水稻秧盘育秧精密播种流水线硬、软秧盘自动叠放的装置,有效地提高了流水线的生产率,并减轻了劳动强度。该装置以可编程控制器PLC为控制核心,由接近开关检测待叠秧盘,控制秧盘升降机构实现秧盘升降的自动叠放,采用土壤防漏机构的气动移动盖板来防止秧盘内的土壤在叠盘过程中发生侧漏而使种子外露。为检测自动叠盘装置的工作性能,以叠盘成功率及种子外露率为指标,以秧盘升降机构的升降速度、盖板方式和生产率为影响因素,设计了三因素三水平正交试验。试验结果表明,升降速度对叠盘成功率影响较大,盖板方式和升降速度对种子外露率影响较大;当升降速度为0.15 m/s、采用气动移动盖板和生产率为600~800盘/h时,硬、软秧盘的叠盘成功率分别为100%与99%~100%;硬、软秧盘的种子外露率最大分别为0.28%与0.60%,试验指标满足水稻秧盘育秧精密播种流水线育秧技术使用要求。

蔬菜钵苗旋转式取苗机构动力学分析与试验

针对一种应用于蔬菜钵苗全自动移栽机的旋转式取苗机构——偏心齿轮-非圆齿轮行星系取苗机构,建立机构的动力学模型,采用动力学方程组序列求解法进行求解,得到机构在一个工作周期内链条、太阳轮轴心、中间轮轴心、行星轮轴心、太阳轮与中间轮啮合点、中间轮与行星轮啮合点等处的受力随行星架转角变化的规律。设计了机构的物理样机,开展机构动力学试验,测试得到机构物理样机在4种不同工作转速下的动力学特性,同时验证了机构动力学模型的正确性。

蔬菜自动移栽机对置秧盘交替自动取投苗机构研究

针对现有蔬菜自动移栽机茎秆夹持式和钵体顶出式取苗方式的缺点,基于顶出-夹取结合式取苗方式,设计了一种适用于对称布置可弯曲秧盘的交替式取投苗机构。阐述了该机构工作原理、关键点运动轨迹和结构组成。分析了关键因素对秧苗夹持点运动轨迹的影响方式并优选了取值:驱动曲柄转速10 r/min,取投苗摇杆长度为309 mm,驱动气缸伸出速度25 mm/s, 0.8 s内完成拔苗,伸出时刻为提前0.4 s。该参数组合下秧苗夹持点在拔苗阶段最大横向位移9.6 mm,累计横向位移0 mm,理论提升高度44 mm,满足取投苗作业理论要求。以苗龄45 d的辣椒秧苗为作业对象,进行了栽植频率70~120株/(min·行)的取投苗性能试验,试验结果表明,该交替取投苗机构在栽植频率100株/(min·行)时可实现取苗成功率93%,投苗成功率95%,总体成功率88%,满足取投苗作业要求,验证了该取投苗机构的可行性。

全自动滑道式旱地钵苗移栽机构设计与试验

针对目前移栽机构取苗速度快导致钵苗易损伤和栽植器在栽植过程中水平方向与地面存在相对运动导致钵苗栽植直立度低等问题,设计了一种全自动滑道式旱地钵苗移栽机构,该机构通过滑道控制栽植臂实现取苗、送苗、栽植和复位功能,使取苗和栽植运动轨迹和运动速度达到最优状态。通过对移栽机构的理论分析,建立运动学模型。基于VB开发了计算机辅助优化设计软件,优化出一组满足理想移栽轨迹要求的机构参数,根据此参数对移栽机构进行整体设计,完成三维建模。应用ADAMS软件对移栽机构进行运动学仿真分析,验证了设计的合理性。在物理样机上利用高速摄像系统进行了轨迹验证试验,通过对比可知理论轨迹、仿真轨迹与样机工作轨迹基本一致,验证了机构设计的正确性。在栽植频率为62株/min工况下进行了机构性能试验,结果表明平均取苗成功率为95%、秧苗平均栽植直立度为82°、秧苗平均直立度合格率为93.4%,满足钵苗移栽要求。

甘草移栽机的设计与运动分析

栽植机械是甘草育苗移栽技术应用、推广的瓶颈,结合甘草移栽的农艺要求,本文设计出一种平移式甘草移栽机,该机采用自动分苗机构和自动移栽机构,可解决分苗、栽苗的难题,并对其工作过程进行了运动分析,确定了自动移栽机构的主动轮和两个从动轮的最佳位置关系,优化了结构参数。

穴盘苗自动移栽机苗盘输送装置的设计研究

针对国内大田移栽中多数采用半自动移栽,主要由人工完成投苗工作及机械完成栽植工作,存在劳动强度大、效率低、移栽质量差等问题,对自动移栽机的苗盘输送装置进行了设计与研究。同时,设计了横向和纵向进给控制机构,确定了关键部件应该满足的技术参数,并进行了三维实体建模分析,验证设计的合理性。结果表明,该装置可满足移栽机苗盘自动输送的要求。

穴盘苗自动移栽机苗盘回收机构设计与试验

为实现穴盘苗移栽全自动化，在自制的穴盘苗自动移栽机上设计了苗盘自动回收机构。该机构主要由输送带、托举凸轮、限位块和集盘架组成。取苗完成后的苗盘以一定的倾角下落至输送带上，再输送至集盘架下方，由托举凸轮托举苗盘至集盘架内的限位块上，以完成自动回收。苗盘的下落倾角β、托举凸轮的轮廓半径R和转速n是实现苗盘自动回收的主要影响因素。单因素试验结果表明，苗盘下落倾角β为55°-65°，托举凸轮的轮廓半径R为120～160mm，托举凸轮转速为30～120r／min，可实现苗盘自动回收。多因素正交试验结果表明，苗盘的下落倾角β为60°，托举凸轮轮廓半径R为140mm，凸轮转速n为30r／min，是实现苗盘的自动回收较佳组合。

穴盘苗温室多末端移栽机运动定位装置设计与试验

为了提高穴盘苗温室移栽机械的自动化程度和移栽效率,对温室穴盘苗多末端移栽机运动定位装置进行了设计。基于多末端执行器联合作业的要求,对其分散装置进行力学分析计算,以实现多个末端执行器等间距移动。对系统进行移位检测试验,检测移栽过程中位置精度,结果表明:128穴盘、4孔花盆自动取苗移位平均值分别为32.291 1、206.324 6mm;通过单样本t检验发现,在0.05显著性水平下,实测取苗移位间隔与设计的穴孔间隔无显著性差异,验证了所设计自动取苗移位装置的可靠性。

顶夹组合式全自动移栽机的设计研究

针对目前穴盘苗向大田移栽,人工移栽成本高、移栽周期长、成熟期不一致、不利于机械化收获等问题,对新疆生产建设兵团大面积种植的辣椒穴盘苗物料特性进行测试。根据种植的辣椒苗物料特性,设计了一种顶夹组合式穴盘苗全自动移栽机。文中主要介绍了全自动移栽机的取苗、运苗和投苗的过程,全自动移栽机的组成和工作原理及其关键部件的设计。所设计的全自动移栽机对新疆棉花、番茄和辣椒等大面积种植的经济作物机械式移栽有良好的推动作用,大大减少了农业对劳动力的需求,增加农民的经济收入,对新疆的农业经济发展具有十分重要的意义。

小型穴盘苗全自动移栽机取苗机构的设计与试验

针对国内低矮温室蔬菜大棚的尺寸限制问题,设计一种小型全自动移栽机,为提高取投苗成功率,减少穴盘苗损伤,重点对取苗机构进行了设计.该取苗机构使用气动加刹车线柔性变距机构实现变距投苗功能,与直动往复式分苗机构配套使用,可以实现静态投苗、静态接苗,提高取投苗成功率,避免出现挂苗现象,并通过试验对取投苗效果进行了检验.试验发现:针对须根类幼苗,当栽植频率为40株·min^(-1)·行^(-1)时,黄瓜苗的取苗成功率为99.31%,投苗成功率为99.31%,综合取投苗成功率达到98.61%,当栽植频率为60株·min^(-1)·行^(-1)时,黄瓜苗的取苗成功率为98.61%,投苗成功率为99.29%,综合取投苗成功率达到97.22%;针对直根类幼苗,当栽植频率为60株·min^(-1)·行^(-1)时,辣椒苗的取苗成功率为97.92%,投苗成功率为99.29%,综合取投苗成功率达到95.83%.试验结果表明,该机构满足蔬菜穴盘苗取投苗要求,且适用于不同品种蔬菜钵苗的取投苗.