Design And Experiment Of New Seedling-fed Device For High-speed Rice Transplanter

Mechanization of rice pot seedling and pot-blanket seedling transplanting can output ofrice per unit area, and rice cropping index in a specific area, while shortening the rice plantingperiod. Seedling-fed device is one of the key work components of a rice high-speed transplanter,functioning in conveying seedlings accurately and stably for rice transplanting mechanism sothat it is able to pick up seedlings one by one pot. At present, there are few studies both inChina and abroad for seedling-fed device for pot seedling or pot-blanket seedling. And existingdevices, with complex structures, are generally of low work efficiency and precision.In this paper, two seedling-fed devices were designed for rice pot seedling and pot-blanketseedling respectively. And this work is based on the request of high-speed rice transplanter forimproving the accuracy and stability of the devices. The contents of research and experimentare as follows:1) The common seedling-fed devices of rice planting machines in the world werereviewed. Firstly, their working theories were studied. Secondly, their advantages anddisadvantages were analyzed. Finally, based on the review, specific requirements were raisedfor designing rice pot seedling and pot-blanket seedling-fed devices.2) First of all, a vertical seedling-fed device was designed with four-bar linkage andratchet mechanism, and this eliminated cumulative errors which existed originally when usingone-way bearing. Secondly, by substituting double-sided timing belt for the single-sided, theslip of seedlings on the conveying belt was avoided. What is more, a fixed-connected and anelastic resisting locking mechanism were designed. The former fixes the position that riceseedling to seedling box in the process of non-vertical seedling-fed, and the latter solve theproblem of overswing on completion of vertical seedling-fed.3) A kinematics model of rice pot-blanket seedling device was established. ThenMATLAB was used to work out the necessary parameters, three-dimensional modeling andvirtual simulation. Based on this, an experimental prototype was constructed and experimentedrigorously. The testing results indicated that the deviation of one-pass vertical feeding is lessthan2mm when the transplanting machine is working at efficiency of250times/min. Theexperiment also showed that there is no accumulative error after repeated feeding, that the seedling is fixed on the conveying belt stably, and that transplanting mechanism can pick upseedlings one by one pot.4) A new vertical seedling-fed device and a new lateral seedling-fed device were designedfor rice pot seedling transplanting mechanism. The former can lock in advance, whichguarantees that vertical seedling-fed is accurate and stable; the latter realizes moving boxperiodically and non-uniformly, which diminishes the moving distance of seedling box in theprocess of picking up seedlings.5) A kinematics model of the new vertical seedling-fed device was figured and a set ofoptimized designing parameters are obtained with optimized analysis software. Cammechanism was also designed correspondingly to eliminate the shock and vibration in verticalseedling-fed. In addition, Joint Modeling and Simulation Environment (JMASE) were carriedout for vertical and lateral feeding device.6) A test bed was developed to examine the kinematics characteristics of the seedlingbox’s lateral motion of the new seedling-fed device, and test the stability and accuracy invertical seedling. The experiment showed that the lateral seedling-fed device is qualified, thedeviation of one-pass vertical feeding is less than2mm in high speed working condition, andthat there is no accumulative error or miss out after repeated feeding.7) A complete seedling-fed device for pot seedling was developed, which laysfoundations in researching and developing riding type trans-planter.