基于FANUC系统速度前馈提高CNC机床加工精度的研究

Research on Improving Machining Precision of CNC Machine Based on Velocity Feed-forward of FANUC System

针对高速高精加工过程中,因数控伺服系统时滞而导致的指令轨迹与实际轨迹存在偏差、进而导致形状误差的问题,将前馈控制引入数控机床伺服系统。通过理论分析可知:选用适当的前馈控制器,可以有效减小形状误差。数控机床测试结果表明:通过调整速度前馈系数,可以提高速度环的增益,从而减小因加速度变化引起的形状误差,改善表面精度和加工形状精度,进而提高CNC机床的加工精度。

CNC servo system has time delay in machine process of high-speed and high-precision which would cause form error because of deviation between instruction and real trajectory. Feed-forward control was introduced into servo system of CNC machine. Through theo- retical analysis, it is shown that the form error can be effectively reduced by adopting proper feed-forward controller. CNC machine test re- sults show： by adjusting the speed feed-forward coefficient, the speed loop gain can be improved, the form error due to changing accelera- tion is reduced, so surface quality and form precision are increased. Further the precision of CNC machine tools is improved.