Research On Wide-narrow Distance Transplanting Mechanism With The Requirement Of Spatial Traiectoarv And Attitude

The technology of rice wide-narrow distance transplanting is based on domestic riceplanting requirements presented by agronomic experts. It is guaranteed by the premise of thenumber of seedlings planted, through wide row planting with narrow row spacing to increaseventilation, lighting, so as to prevent the disease, lodging, increase production (increase rate ofmore than4%), assure the rice quality. As the traditional transplanter can only form the planetransplanting trajectory and can’t be achieved wide-narrow distance planting, and the existingwide and narrow transplanter do not match the equipment of raising rice seedlings, so theexisting wide and narrow machine failed to get promotion. Still it is relied on manual pull widerow and narrow row line in the paddy field and planting, seriously affect the majority of farmers’production enthusiasm, restrict the development of organic rice production.The difference between wide-narrow distance transplanter and traditional equal row spacingtransplanter is the core components "Transplanting Mechanism". Equal row spacingtransplanting mechanism can form a planar trajectory. Seedling planting row spacing is the samewith the distance between seedling doors (e.g.30cm). The wide and narrow distancetransplanting mechanisms achieve non-equidistant planting rows in traditional seedling door. Itsplanting trajectory requires spatial characteristics. Due to the absence of wide and narrowplanting patterns and corresponding wide-narrow distance transplanter, so it can’t through theway of absorbing, digesting and improving to develop wide-narrow distance transplantingmechanism. Therefore, to carry out innovative design and theoretical studies of the wide-narrowdistance transplanting mechanism with spatial transplanting trajectory has important applicationvalue for the development of wide-narrow distance transplanter. In this dissertation, thekinematic and dynamic characteristics of the wide-narrow distance transplanting mechanismwith spatial planetary gear train were studied by the way of theoretical analysis and experimentalverification as well as the mechanism parameters and dynamic performance. Finally, a quicklydesign platform for wide-narrow distance transplanting mechanism was established. The mainresearch contents and results are as follows:(1)The home and abroad transplanting mechanism working principles that have planartrajectory and spatial trajectory were studied and the problems of application of planetary gearstrains in the wide-narrow distance transplanting mechanism were analyzed. The forward andreverse design methods for different types of the transplanting mechanism with spatial planetarygear trains were expounded. The design method of the spatial transmission gear tooth profile andnumerical model of the noncircular bevel gear tooth profile on spherical surface was studied.After developing the calculation program, the rapid design of noncircular bevel gear wasrealized.(2) The advantages and disadvantages about the different spatial planetary gear train mechanism used in the design of the wide-narrow distance transplanting mechanism based on theshape property of planting trajectory (e.g. have small side offset in grasping seedling and smallhole) were analyzed. Then a conclusion was made that the staggered axis and the intersectantaxis compound planetary gear train mechanism and two-stage intersectant axes planetary geartrain mechanism have the potential to achieve spatial kidney-shaped trajectories and spatialdolphin-shaped trajectories that have the character of small side offset and plant holerespectively.(3) A wide-narrow distance transplanting mechanism with staggered helix gear andnoncircular bevel gear planetary gear train applied in high-speed wide-narrow distancetransplanter was put forward. The kinematic model was established and the mechanismkinematics characteristic was analyzed. After giving the9optimization goals about wide-narrowdistance transplanting mechanism, the functional relationship between optimization objectivesand mechanism parameters were expressed. Optimization program was compiled by usingMatlab software, and a set of parameters required to meet planting was obtained.(4) Physical prototype of wide-narrow transplanting mechanism was manufactured. Basedon transplanter currency test-bed, the shape of trajectory, velocity and attitude of seedling pawwas tested by using high-speed digital camera. After developing a wide-narrow distancetransplanting test-bed which is used on rotary trial soil bin, a series of tests were carried out withno seedling and seedling and the planting hole, line spacing, row spacing, upright degree,damaged seedling, laid seedling was measured. All of the inspected results agree with therequirements of planting seedling, which give a convincing proof to verify the theoretical modeland design method of the transplanting mechanism.(5) The dynamic analysis of wide-narrow distance transplanting mechanism with staggeredhelix gear and noncircular bevel gear train was made as well as its dynamics model. Thedynamic performance was optimized by appending counterweight on the panting arm and thedynamic test bench which is used to verify the dynamics performance was improved. The testingresults conduct that appending counterweight on the planting arm is a valid method to improvethe dynamic performance of transplanting mechanism.