面向特定轨迹与姿态要求的轮系式移栽机构构型综合与设计方法研究

Aiming at the problem of the transplanting mechanism with gear trains is unable to realize rice pot seedling wide-narrow row & zigzag transplanting (RWZT) by dimensions optimization to further improve its trajectory and attitude, an automatic synthesis method of epicyclic gear trains with transplanting functions is studied in term of kinematic trains graph, and then a non-monotonic RWZT mechanism with spatial large-ring and straight-clip trajectory is proposed. 1) The structural conditions of gear trains which fit the kinematic properties of transplanting are analyzed. The isomorphic identification method of initial assignment, indefinite and fixed reassignment, and adjacency value analysis is proposed, and the automatic synthesis of gear trains and their atlas are achieved. 2) The high amplitude, multi fluctuation and positive & reversion rotation characteristics of the input and output transmission law of gear trains are studied, and the classification of mechanisms is done according to their performance ability on trajectory and attitude. A model for solving spatial gear trains with a given trajectory is set up, and the inverse structural synthesis of RWZT mechanism is realized. 3) The heuristic optimization method which can control the optimization process is proposed, and the optimal dimension and attitude of the mechanism is obtained. A digital design platform is established, the prototype and its testing is made. Eventually, the universal design theory and method are established, laying a theoretical foundation for development of new RWZT machine, playing an important role in promoting the sustainable development of our rice transplanter industry.

针对现在轮系式移栽机构无法通过尺度优化进一步改善其轨迹和姿态以满足水稻钵苗宽窄行Z字形移栽的问题。本项目拟以图论和组合优化理论为基础，开展适合移栽用的周转轮系自动综合方法研究，提出空间大环扣、直夹式非单调周转轮系钵苗宽窄行Z字形移栽机构。1）分析符合移栽运动特性的轮系结构条件，提出并研究初始赋值、定值与不定值动态赋值和邻接值分析的同构判别方法，实现轮系运动链构型自动综合并建立适合移栽的轮系图谱；2）研究轮系输入输出传动规律的高幅值、多波动与正反转特性，实现轮系在轨迹和姿态表现能力评价与分级，建立基于给定轨迹的空间轮系机构求解模型，实现钵苗宽窄行Z字形移栽机构逆向综合；3）提出并研究优化过程可控的启发式参数优化方法，实现机构的姿态和尺度优化，建立快速设计平台、试制样机并测试移栽性能。最终，形成一套适用于轮系式移栽机构设计的普适性理论与方法，对促进我国移栽机行业可持续发展具有迫切的现实意义。

针对现在轮系式移栽机构无法通过尺度优化进一步改善其轨迹和姿态以满足水稻钵苗宽窄行Z字形移栽等具有复杂移栽轨迹和姿态要求的机构设计问题。项目以图论和组合优化理论为基础，从运动链胚图出发，开展了运动链单色图、双色图、行星轮系图的自动综合理论研究。建立了面向种植农艺服役环境的移栽用行星轮系机构的筛选准则，实现了具有移栽运动特征的行星轮系机构构型创新，建立了移栽机构设计的行星轮系构型库。结合移栽机构所需的传动比高幅值、多波动和机构局部输出正反转特性，引入不等速传动规律推导了非圆齿轮节曲线凸性判定公式，给出了非圆齿轮行星轮系机构描述移栽轨迹能力的定性判别条件。研究了基于预期运动轨迹和特定农艺作业姿态要求的不同行星轮系机构尺度综合，完成了中心解析域内行星轮系机构信息参数图求解，建立了含若干位置姿态的轨迹、总传动比、非圆齿轮圆度性之间的联系。建立了基于运动映射法、几何约束法的轮系机构主体参数求解模型，并基于消元法、多面体同伦延拓实现参数求解。研究了移栽机构农艺要求与机构优化分离模型，建立了以移栽轨迹形状可控点位置坐标为设计变量，移栽机构干涉等为约束条件，非圆齿轮节曲线凸性指标为优化目标的优化模型，实现了移栽机构优化目标和参数降维。研制了用于水稻钵苗移栽试验的取苗试验台和直线运动土槽试验台，设计了夹苗/夹钵式用于钵苗宽窄行Z字形移栽、钵苗宽窄行移栽、钵苗移栽等多种不同作业要求的移栽机构，并开展了物理样机加工、轨迹姿态测试、取苗移栽试验等。本项目研究建立了一套适用于行星轮系式移栽机构构型创新、尺度综合、研制试验的理论和方法，研究成果对种植机械中育苗移栽装备的研发具有积极意义。