柔性并联机器人的动力学性能研究

发布时间：2018-11-28 16:41

【摘要】：随着航天科学技术的不断发展,人类对机构的精度和稳定性的要求越来越高,于是人们迫切寻找一种机构在高速,轻质运动的条件下的运动学和动力学的分析方法。构件在高速,轻质,重载的条件下运动,一定会发生变形,也就是要将容易变形的构件作为柔性构件来分析。并联机器人一直是机器人领域中的前沿课题之一,并联机器人具有惯性小,累积误差小,刚度大,运动精度大,稳定,运动学反解容易获得等优点。弥补了串联机器人在高速,轻质,高精度领域的空白。因此同时具有柔性机构和并联机构两方面的特点的柔性并联机器人成为机器人领域的一个非常重要的研究方向。进行这方面的研究具有重要的意义。本文在研究前人研究的基础上,以三自由度空间并联机构为分析对象,对3-RRRT并联机器人机构进行运动学和动力学建模。然后进行虚拟样机仿真,对机构的受力特性,动态特性做了更加全面的分析。首先对3-RRRT并联机器人运用D-H坐标法在其上关节处建立了坐标系,得出了机构位置反解,驱动角位移随时间的变化,角速度随时间的变化,角加速度随时间的变化曲线。其次运用牛顿欧拉递推法给出了其递推的力分析过程。并且建立了力和力矩的平衡方程。运用MATLAB进行数值求解,最终求得其逆动力学解,得出驱动杆件所需的驱动力矩随时间的关系。然后运用SOLIDWORKS建立其三维模型,共分为三部分,动平台,静平台,和三条支链(每条支链三个杆)。然后导入到ADAMS中进行关节约束的建立,对其进行刚体逆运动学和正向动力学仿真,得出驱动力矩曲线和杆件受力曲线。最后在ANSYS经典界面中对每条支链的第三个杆进行了网格的划分,将其变为柔性。首先设置材料弹性模量,泊松比,密度等参数,输出为MNF格式文件,然后导入到ADAMS中替换掉刚体。然后进行刚柔耦合仿真(动平台和静平台属于刚体,每条支链的第一个杆和第二个杆是刚体,第三个杆是柔体)得出了在刚柔混合的情况下的末端轨迹,然后与刚体的状态下作比较。得出其运动轨迹的特性,以及柔性杆件所受应力的变化曲线。
[Abstract]:With the development of spaceflight science and technology, the requirements for the accuracy and stability of the mechanism are becoming higher and higher. Therefore, it is urgent to find a kinematics and dynamics analysis method of the mechanism under the condition of high speed and light motion. Under the condition of high speed, light weight and heavy load, the component must be deformed, that is to say, the easily deformed member should be analyzed as a flexible member. Parallel robot has always been one of the frontier topics in the field of robot. Parallel robot has the advantages of small inertia, small cumulative error, large stiffness, large motion precision, stability, easy to obtain kinematics inverse solution and so on. It makes up the blank in the field of high speed, light weight and high precision. Therefore, the flexible parallel robot with the characteristics of both flexible mechanism and parallel mechanism has become a very important research direction in the field of robot. The research in this field is of great significance. In this paper, based on the previous research, the kinematics and dynamics model of 3-RRRT parallel manipulator is established by taking the spatial parallel mechanism of three degrees of freedom as the analysis object. Then virtual prototype simulation is carried out, and the mechanical and dynamic characteristics of the mechanism are analyzed more comprehensively. Firstly, the coordinate system of 3-RRRT parallel robot is established by D-H coordinate method, and the position inverse solution of the mechanism is obtained. The change of the driving angular displacement with time, the change of angular velocity with time, and the curve of angular acceleration with time are obtained. Secondly, the force analysis process of Newton Euler recursive method is given. The equilibrium equations of force and torque are established. The inverse dynamic solution is obtained by using MATLAB, and the relationship between driving torque and time is obtained. Then SOLIDWORKS is used to build its 3D model, which is divided into three parts: moving platform, static platform, and three branching chains (three rods for each branch chain). Then it is introduced into ADAMS to establish the joint constraint, and the inverse kinematics and forward dynamics of rigid body are simulated, and the driving moment curve and the force curve of the bar are obtained. Finally, the third bar of each branch chain is meshed in the ANSYS interface to make it flexible. The parameters such as elastic modulus, Poisson's ratio, density and so on are first set and output to MNF format file, then imported into ADAMS to replace rigid body. Then the rigid-flexible coupling simulation (the moving platform and the static platform belong to the rigid body, the first rod and the second rod of each branch chain are rigid body, the third bar is the flexible body) and the end trajectory is obtained in the case of rigid and flexible mixing. Then it is compared with the rigid body. The characteristics of the motion track and the curve of the stress of the flexible member are obtained.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP242

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