摘要
Delta并联机构具有速度快、运动精度高、灵活性强等特点,非常适合穴盘育苗过程中的移钵作业及补苗需要。基于三自由度Delta并联机构和气动取苗爪,设计了一种高速钵苗移栽机器人。通过建立Delta并联机构的单支链约束方程,求解出钵苗移栽机器人的可达工作空间;为使其可达工作空间尽可能接近设计工作空间,以机构雅可比矩阵条件数作为惩罚条件,建立起兼顾钵苗移栽机器人整机尺寸与运动学性能的尺度综合目标函数,并应用遗传算法得到机构最优尺寸参数。根据盘到盘钵苗移栽的运动要求,对移栽轨迹进行规划并选取五次多项式作为移栽动平台的运动规律函数。基于机构尺度综合和轨迹规划设计物理样机,并进行盘到盘的钵苗移栽和健壮苗补苗性能试验,结果表明:随着移栽动平台携苗运动最大加速度的提高,钵土破碎率逐渐加大,钵苗移栽合格率逐渐降低,在最大加速度amax为30 m/s2时,钵苗移栽合格率可达95.5%,移栽速率可达2 149株/h,在此加速度下进行健壮苗补苗试验,补苗合格率可达92%,证明了将Delta并联机构用于钵苗移栽机器人的可行性,以及尺度综合和轨迹规划的合理性。
Delta parallel mechanism is effective in speed, kinematic accuracy and flexibility, which is appropriate for the plug seedling transplanting and healthy plug seedling filling, thus a high-speed plug seeding transplanting robot was designed by using Delta parallel mechanism with a pneumatic manipulator. The reachable workspace of the plug seedling transplanting robot was obtained by building the single chain constraint equations of the Delta parallel mechanism; taking the condition number of Jacobian matrix as the penality condition, a dimensional synthesis target function was built considering the size and kinematic performances of the plug seeding transplanting robot for the purpose of making the reachable workspace close to the needing workspace, then the dimensional synthesis for the plug seedling transplanting robot was obtained by using the genetic algorithm. In accordance with the motion demand of plug seedling translating robot, trajectory planning was carried out and quintic polynomial motion law was taken as the principle of operation for the moving platform. Based on the mechanism dimensions and trajectory planning, a physical prototype was built and transplanting experiment was carried out. The experiment results showed that the success rate of plug seedling transplanting was decreased when the transplanting acceleration was increased, the success rate of plug seeding transplanting was up to 95.5% , the success rate of plug seeding filling was up to 92% , transplanting rate can reach 2 149 plants per hour when the transplanting acceleration was 30 m/s^2, which demonstrated the practicability and rationality of the dimensional synthesis and trajectory planning when the Delta parallel mechanism was used in plug seedling transplanting.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2017年第5期28-35,共8页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金项目(51475216)
"十二五"国家科技支撑计划项目(2013BAD08B03)
江苏省科技支撑计划(农业)项目(BE2014373)
江苏省农业科技自主创新资金项目(CX(15)1033-5)
江苏高校优势学科建设工程项目(苏政办发[2014]37号)
关键词
钵苗移栽
并联机构
尺度综合
轨迹规划
性能试验
plug transplanting
parallel mechanism
dimensional synthesis
trajectory planning
performance test
