基于Delta并联机构的移栽补苗机器人设计研究

发布时间：2018-04-24 07:40

本文选题：钵苗移栽 + 尺度综合　；参考：《江苏大学》2017年硕士论文

【摘要】：在现代温室的穴盘育苗生产中,常常需要将穴盘苗从密度较高的育苗穴盘移栽到密度较低的育苗穴盘或对需要补苗的穴孔进行补苗作业。然而在我国现阶段的育苗温室中,钵苗的移钵和补苗作业仍以人工作业为主,人工移钵或补苗的工作方式不仅人工成本较高,而且效率和质量较低,不符合现代农业机械化、集约化的发展要求。因此,急需一种自动化移栽补苗装备与其配套。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。为此,本文基于三自由度Delta并联机构和气动取苗爪,设计了一种移栽补苗机器人。主要研究内容如下:1)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;根据钵苗移栽机器人盘到盘移栽、补苗的作业要求,确定出钵苗移栽机器人的设计工作空间;基于其设计工作空间,对钵苗移栽机器人进行尺度综合,为使钵苗移栽机器人可达工作空间尽可能接近设计工作空间,并保证其在设计工作空间内具有良好的运动学性能,建立起兼顾钵苗移栽机器人工作空间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。2)为提高移栽补苗机器人的移栽效率和质量,对按行移栽和按列移栽两种移栽方案进行优选,确定按列移栽的移栽方案;基于移栽补苗机器人盘到盘移栽、补苗的工作方式,对其移栽和补苗轨迹进行规划,并选取5次多项式规律作为移栽、补苗轨迹的控制函数。基于移栽补苗机器人运动学逆解和轨迹规划,通过等时插补、运动学逆解和速度拟合,将移栽补苗机器人末端执行器的移栽或补苗轨迹转换为Delta并联机构三主动臂的转动规律;对移栽补苗机器人的移栽和补苗作业流程进行设计,实现移栽补苗机器人在工作区域内以按规划的移栽路径完成移栽、补苗作业。3)基于移栽补苗机器人尺度综合与轨迹规划,建立移栽补苗机器人虚拟样机模型,选取移栽补苗机器人工作空间中两条最远轨迹,进行虚拟样机仿真;仿真得出移栽动平台的速度、加速度曲线,其变化规律符合移栽、补苗作业的运动要求,验证了轨迹规划的合理性;同时,仿真还得出移栽补苗机器人三主动臂的角速度、角加速度、转矩的变化曲线,为移栽补苗机器人三主动臂电机的选型提供理论基础。4)基于尺度综合、轨迹规划和虚拟样机仿真,研制物理样机,进行穴盘到穴盘的钵苗移栽和补苗性能试验,结果得出:随着移栽动平台携苗运动最大加速度的增大,钵土破碎率逐渐增大,钵苗移栽合格率逐渐降低,在最大加速度amax为30m/s2时,钵苗移栽合格率可达95%,移栽速率可达2149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、轨迹规划和仿真分析的合理性。
[Abstract]:In the modern greenhouse, it is often necessary to transplant the seedlings from the higher density to the lower density or to make up the holes needed to supplement the seedlings. However, in the greenhouse of seedling raising in our country at the present stage, the work of moving bowl and repairing seedling is still dominated by manual work. The work mode of moving bowl or supplement seedling is not only high labor cost, but also low efficiency and quality, which does not accord with modern agricultural mechanization. Intensive development requirements. Therefore, it is urgent that a kind of automatic transplanting seedling repair equipment and its matching. Delta parallel mechanism have the characteristics of fast speed, high kinematic precision and strong flexibility, which are very suitable for the transplanting bowl operation and the need of seedling mending in the seedling raising process of hole plate. In this paper, a transplanting seeding robot is designed based on a 3-DOF Delta parallel mechanism and pneumatic claw. The main research contents are as follows: (1) by establishing the single branch chain constraint equation of the Delta parallel mechanism, the reachable workspace of the potted seedling transplanting robot is solved. The design workspace of the potted seedling transplanting robot is determined. Based on the design workspace, the scale synthesis of the bowl seedling transplanting robot is carried out, so that the workspace of the bowl seedling transplanting robot can be as close as possible to the design workspace. It is guaranteed that the robot has good kinematic performance in the design workspace, and a scale integrated objective function is established which takes into account both the workspace and kinematics performance of the transplanting robot. In order to improve the transplanting efficiency and quality of transplanting and seedling filling robot, two transplanting schemes were selected according to row transplanting and row transplanting, and the transplanting scheme according to row was determined. Based on the working mode of transplanting and repairing seedlings, the transplanting and seeding trajectory of transplanting and filling seedling robot is planned, and the law of 5th degree polynomial is selected as the control function of transplanting and repairing seedling track. Based on the kinematics inverse solution and trajectory planning of transplanting and seeding robot, through isochronous interpolation, kinematics inverse solution and velocity fitting, the transplanting or seeding trajectory of the end effector of transplanting and seeding robot is transformed into the rotational rule of three active arms of Delta parallel mechanism. This paper designs the transplanting and seeding operation flow of transplanting and seeding robot, realizes the transplanting of transplanting and seeding robot in the working area according to the planned transplanting path, and seedling mending operation .3) based on the scale synthesis and trajectory planning of transplanting and seeding robot. Establish the virtual prototype model of transplanting and seedling filling robot, select two furthest tracks in the workspace of transplanting seeding robot, carry on virtual prototype simulation, and get the velocity and acceleration curve of transplanting moving platform, its changing law accords with transplanting. The kinematic requirements of the seeding operation verify the rationality of the trajectory planning. At the same time, the angular velocity, angular acceleration and torque curves of the three active arms of the transplanting seeding robot are obtained by simulation. Based on scale synthesis, trajectory planning and virtual prototype simulation, a physical prototype was developed for transplanting seedling robot with three active arm motors. The results showed that with the increase of the maximum acceleration of seedling carrying on the transplanting platform, the rate of soil fragmentation gradually increased, and the qualified rate of transplanting was decreased gradually, when the maximum acceleration amax was 30m/s2, The qualified rate of transplanting seedling in bowl can reach 95%, and the rate of transplanting can reach 2149 / h. Under this acceleration, the test of robust seedling filling is carried out, and the qualified rate of seedling replacement can reach 92%. It is proved that the feasibility and scale synthesis of using Delta parallel mechanism in transplanting robot of potted seedling is proved. The rationality of trajectory planning and simulation analysis.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S223.9

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