具有全周运动的抓取机器人的设计与研究

发布时间：2018-02-27 12:08

本文关键词： 全周运动并联机构运动学分析尺寸优化样机实验　出处：《北京交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：抓取机器人作为机器人机构在工业机器人领域的重要应用之一,有着广阔的发展潜力和无可限量的应用前景。串联式抓取机器人因为工作空间较大,起步较早所以其理论相对完善,控制系统较为简单等优点,在抓取机器人市场占据着主流位置,然而串联式机器人由于其结构特点,存在着刚度较差、精度较差,存在累积误差和末端件惯性较大等缺点;目前市场上应用于抓取操作的并联机器人的构型主要以Delta机构和Par4机构为基础,然而相比于串联式结构,此类并联机器人存在着工作空间小,末端动平台姿态转角小等缺点,这些缺点在很大程度上限制了其在抓取领域的应用。针对上述问题,本次研究的目的是采用并联机构,设计一种具有全周运动的抓取机器人,使其手爪能够实现无限制的转动。本文应拥有无限转动能力的并联抓取机器人的市场需求,设计了一种拥有两个移动,一个转动的平面三自由度的并联抓取机器人。首先,本文结合机器人机构学的运动学分析理论,建立了抓取机器人的数学模型,在此基础上,基于螺旋理论对其自由度进行了求解,对其进行了运动学反解、正解的计算和速度分析;基于得到的运动学反解运用二维搜点法绘制了抓取机器人的在平面内的位置工作空间,并分析了抓取机器人不同的杆长参数变化时对其工作空间的影响,然后对抓取机器人的奇异性基于雅克比矩阵进行了分析,得到了其工作空间内的雅克比条件数,在雅克比矩阵基础上对机构进行了灵巧性分析和静刚度分析;然后根据机器人的结构特点和杆长参数变化对工作空间的影响的大小,确定了机器人的优化变量和约束条件,以抓取机器人的整体静刚度和位置工作空间为目标函数,基于NSGA-II遗传算法对抓取机器人进行了杆长尺寸优化设计,从优化结果中选取了其中的最优解作为抓取机器人机构的设计参数;接着利用Creo2.0软件建立了机器人的三维模型并导入ADAMS软件中进行了运动学仿真,并对比基于MATLAB的运动学逆解计算结果验证了动力学仿真的正确性,在此基础上基于给定的抓取和放置任务进行了轨迹规划;最后,对抓取机器人利用有限元分析的方法进行了静力学分析,利用3D打印机制作了模型,并最终制作了物理样机。研究结果表明所设计的具有全周运动的抓取机器人拥有平面内的三个自由度,且抓取机器人的手爪部分能够实现无限制的转动,满足了并联式抓取机器人的设计要求。
[Abstract]:As one of the important applications of robot mechanism in the field of industrial robot, grab robot has broad development potential and unlimited application prospect. Because of its relatively perfect theory and simple control system, it occupies the mainstream position in the grab robot market. However, because of its structural characteristics, series robot has poor stiffness and poor precision. At present, the configuration of parallel robot used in grab operation is mainly based on Delta mechanism and Par4 mechanism, but compared with series structure, This kind of parallel robot has some disadvantages, such as small workspace, small attitude angle of the terminal moving platform, and so on, which to a great extent limits its application in the field of grasping. In view of the above problems, the purpose of this study is to adopt parallel mechanism. A grab robot with full cycle motion is designed to realize unlimited rotation of its claws. In this paper, the market demand of a parallel grab robot with infinite rotation capability is proposed, and a kind of parallel grab robot with two movements is designed. A rotating planar three-degree-of-freedom parallel grab robot. Firstly, the mathematical model of the grab robot is established based on the kinematics analysis theory of the robot mechanism. Based on the spiral theory, the degree of freedom is solved, the kinematics inverse solution, the forward solution and the velocity analysis are carried out, and based on the obtained inverse kinematics solution, the workspace of the position of the grab robot in the plane is drawn by using the two-dimensional search point method. Then the singularity of the grab robot is analyzed based on the Jacobian matrix, and the Jacobian condition number in the workspace is obtained. The dexterity analysis and static stiffness analysis of the mechanism are carried out on the basis of Jacobi matrix, and the optimization variables and constraint conditions of the robot are determined according to the structure characteristics of the robot and the influence of the change of the rod length parameter on the workspace. Taking the whole static stiffness and position workspace of the grab robot as the objective function, the rod length optimization design of the grab robot is carried out based on NSGA-II genetic algorithm. The optimal solution is selected as the design parameter of the grab robot mechanism from the optimization results, and then the 3D model of the robot is established by using Creo2.0 software and the kinematics simulation is carried out in the ADAMS software. The results of inverse kinematics solution based on MATLAB are compared to verify the correctness of the dynamic simulation. Finally, the trajectory planning is carried out based on the given grab and placement tasks. The static analysis of grab robot using finite element analysis method is carried out, and the model is made by using 3D printer. Finally, a physical prototype is made. The results show that the designed grab robot with full cycle motion has three degrees of freedom in the plane, and the claw part of the grab robot can be rotated without restriction. The design requirements of parallel grab robot are satisfied.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP242

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