空间刚柔耦合并联机器人动力学建模及仿真

Dynamic modeling and simulation of the space rigid-flexible coupling parallel robot

为研究柔性构件对系统运动特性的影响,对空间3-RRRU并联机器人进行了动力学建模及耦合特性的仿真分析。应用矢量闭环法对空间并联机构的逆运动学进行求解,推导出各个构件位置、速度、加速度的变化规律;根据第一类Lagrange方程建立空间全刚性并联机器人的逆动力学模型;运用MATLAB软件对空间并联机构进行仿真,并对动力学数值结果和仿真结果进行对比,以验证模型的正确性。基于ANSYS软件和ADAMS软件,对空间并联机构中的空间梁单元进行柔性替换,通过建立空间刚柔耦合并联机器人模型,分析机构在运动状态下展现出的耦合特性,并与空间全刚性并联机器人进行比较。结果表明:两类模型的末端执行器的运动趋势一致,轨迹误差在0.000 7~0.419 4 mm范围内;梁单元产生的弹性变形对系统运动性能产生了重要影响,因此,建立正确的刚柔耦合动力学模型具有重要的指导意义。

In order to explore the influence of flexible links on the motion characteristics of the system,the space 3-RRRU parallel robot is subject to dynamic modeling and its coupling characteristics are simulated. The inverse kinematics of the space parallel mechanism is solved by means of the vector closed-loop method,and the variation of the position,velocity and acceleration of each component is derived. The inverse dynamic model of the space fully-rigid parallel robot is worked out according to the first type of Lagrange equation. The MATLAB software is adopted to simulate the space parallel mechanism and compare the dynamic numerical results with the simulation results,and thus,the correctness of the model is verified. With the help of the ANSYS software and the ADAMS software,the beam unit in the space parallel mechanism is subject to flexible replacing. In addition,with the model of the space rigid-flexible coupling parallel robot,the coupling characteristics of the moving mechanism are analyzed and compared with those of the space fully-rigid parallel robot. The results show that the end-effectors of the two models have the same trend of motion,and the trajectory error is within the range of 0.000 7~0.419 4 mm. The elastic deformation produced by the beam unit exerts important influence on the system’s motion performance. Therefore,it is of great significance to set up a correct rigid-flexible coupling dynamic model.