顶出托举式钵苗脱盘装置设计与试验

针对现有自动取苗装置作业过程中出现苗体受损、钵体开裂、基质损失率高等问题,该研究设计了一种适应活动苗盘的托举式钵苗脱盘装置。设计了具有纵向、横向及竖直方向定位功能的苗盘三维定位机构和具有苗盘开启与钵苗托举功能的开启-托举机构,并设计了脱盘装置的PLC控制系统。为验证钵苗脱盘装置的作业效果,选取托举速度、端面类型及基质含水率为试验因素,以钵苗在托举台端面上的位置合格率和脱盘过程中钵体基质损失率为评价指标,以16穴活动苗盘模型培育的35 d苗龄油菜钵苗为对象,采用L9(34)正交表设计试验方案进行台架试验。试验结果表明,各因素对钵苗位置合格率和钵苗基质损失率影响的主次顺序依次为托举台端面类型、托举速度、基质含水率;试验获得影响因素的最优组合为托举速度32 mm/s、托举台端面为橡胶面、基质含水率55%。基于优选参数组合进行重复性验证试验,结果表明,钵苗脱盘后托举台端面上的位置合格率为100%,基质损失率为1.56%,满足实际作业需要。该研究可为钵苗自动移栽机取苗机构的研发提供参考。

Design and test of eject lifting type pot seedling detaching device

Aiming at the problems of seedlings injury, seedling pot cracking and high matrix loss rate in the operation process of automatic seedling device, a eject lifting type device for pot seedling detaching from movable tray was designed. The device was mainly composed of seedling tray conveyor, tray positioning mechanism, opening and lifting mechanism and control system. According to the structure of the movable tray, a three-dimensional positioning mechanism composed of half Y shaped positioning bars, guidance positioning wheels and positioning plates was designed to position the tray from longitudinal, transverse and vertical directions, so as to ensure that movable tray could be accurately positioned in operating area. According to the characteristics that the pot hole of movable tray could be opened, an opening and lifting mechanism consisting of short push plate, long push plate and lifting platform was designed. Short push plate and long push plate were sequentially opened by longitudinal side plate and lateral side plate which were used for movable tray positioning so as to separate seedling pot from pot hole. At the same time, after the separation, lifting platform lifted seedling pot which started to slide along the wall of pot hole from bottom and lifted it to the designed height for subsequent operations. The control system of device for seedling detaching from movable tray was designed. PLC controlled the operation of each driving motor according to the outputs signals of the movement sequence of each mechanism, so that each mechanism could coordinate in order to realize the automatic detaching of seedling pot from movable tray. In order to verify the operation effects of the device for seedling detaching from movable tray, bench experiments were carried out. Seedling pot lifting speed, type of the end face of lifting platform and moisture content of matrix of seedling pot were used as experimental factors. The qualified rate of position of seedling pot on the end face of the lifting platform and the loss rate of seedling pot matrix in process of seedling pot detaching from movable tray were taken as the evaluation indexes. Rapeseed seedlings of 35-day-old which were cultured in a 16-hole movable tray were used as the object. An experimental scheme of L9 (34) orthogonal table was used for the bench experiments to study the influence of various factors on the evaluation indexes. Through the range analysis and variance analysis of experimental data, the influence order of each factor on the evaluation indexes were obtained, which were material type of end face of lifting platform, seedling pot lifting speed and moisture content of matrix of seedling pot. At the same time, the optimal parameter combination of the experimental factors was obtained in the experiments: the lifting speed was 32 mm/s, the material of the end face of lifting platform was rubber, and the moisture content of the matrix was 55%. Verification experiments with optimal parameter combination were carried out and the results showed the qualified rate of positions of seedling pot on the end face of the lifting platform was 100% and the loss rate of seedling pot matrix was 1.56%, which indicated that the device for seedling pot detaching from movable tray met the requirement of actual operations. The study provides important theoretical basis and reference for the design and further study on seeding automatic pick-up and transplanting mechanism.