新型3T2R龙门式混联机床动力学模型

Solving Dynamics for a Novel 3T2R Gantry Hybrid Machine Tool

提出了一种以能实现沿X、Z轴平移和绕X、Y轴转动的新型并联机构2-RPU&2-UPS作为主体,辅以能实现主体Y轴滑动的直线导轨来共同实现五坐标联动加工的一种新型龙门式混联机床的机构设计方案。运用螺旋理论分析了该机床实现3T2R运动原理,计算出该机床的自由度,进行输入选取与论证,并进行机床机构奇异分析,提出减少奇异的参数设计条件。建立该机床的位置反解数学模型,推导出了该机床的速度雅可比矩阵和加速度分析表达式,求解了该机床的位置反解、速度和加速度。基于虚功原理和该机床的运动学模型建立该机床的动力学模型,并采用Adams软件对该机床动力学进行模拟仿真,模拟结果表明理论结果完全正确。

A structure scheme for a novel 3T2 R gantry hybrid machine tool（HMT） is proposed.In this scheme,a novel2-RPU2-UPS parallel mechanism is proposed as the machine tool main mechanism,which can realize two-dimensional translations along X,Z-axis and two-dimensional rotations about X,Y-axis,with assistance of a Y-axis direction linear guide,5-axis machining can be realized.The three-dimensional translations and two-dimensional rotations motion of this machine tool are analyzed based on screw theory.The DOF of the mechanism is calculated,and the driving joints are chosen and discussed.The motion singularity is analyzed and the parameter design conditions are presented to decrease motion singularity.The reverse solution of position analysis for this machine tool is presented.On this basis,the Jacobian matrix and acceleration equation are derived,and the inverse position,velocity and acceleration of this machine tool are obtained.The dynamics model is established on the basis of the principle of virtual work and the kinematics model of this machine tool,and the simulation of mechanism dynamics is implemented by using Adams software.The simulation results testify the validity of the analytic model.