高速高加速度下的进给系统机电耦合

Electromechanical Coupling in the Feed System with High Speed and High Acceleration

高速高加速度进给对数控机床提出了更高的要求,也增加了对机电耦合的研究难度。从理论分析和仿真的角度,分别对高速高加速度下,伺服系统、机械系统以及切削力的频率特性以及其时变特性进行分析,探究高速高加速度对进给系统机电耦合的影响。结果表明,随着速度和加速度的增大,机械系统的质量分布会随着位置的不同发生偏移;丝杠螺母副以及轴承副的轴向刚度随着加速度的不同而不同,并且随着加速度的增大,存在刚度突变点;伺服输出力频率特性受电感非线性的影响也发生变化,随着速度的增大;伺服输出力的频率成分增大,频率幅值增大,随着加速度的增大,伺服输出力的频率不变,幅值增大;刀具安装偏置对切削力的影响更加明显,切削力谐波成分增多;各个系统间的相互作用变得更加复杂,机电耦合对运动精度的影响更加凸显。

It is put forward higher requests to the NC machine tool for high speed and high acceleration, which increases the difficulty of the research on the electromechanical coupling. The analysis are carried out from the theory analysis and simulation respectively which involve the frequency characteristics and their variation of the NC system, the servo system, the mechanical system and the cutting force under high speed and high acceleration. Its effects are explored on the electromechanical coupling in the feed system. The results show that with the increase of velocity and acceleration. The distribution of the quality of the mechanical system vary with the position; the axial stiffness of screw nut vice and bearing vice vary with the acceleration, meanwhile, the stiffness exist discontinuity. Because of the nonlinear effects of the inductance, with the increase of velocity, the frequency and amplitude of servo output force increase; with the increase of acceleration, the amplitude of force increases. The influence of cutting tool installation offset on the cutting force become more obvious and the frequency components of cutting force increase. The interaction of each system becomes more compl）~x, and the influence of electromechanical coupling on the dynamic precision become more prominent.