网络化数控系统中，网络介入导致的时间参数( 采样周期与时延) 对数控加工性能的影响不可忽视．文中基于修正 Z 变换理论建立了网络化数控系统模型，确立了时间参数与数控系统加工性能指标的关系，定量分析了其对加工性能的影响机理．结果表明:时延及其抖动增大了多轴加工的轮廓误差; 与时延相比，采样周期是加工性能的主要影响因素; 时延引起的多轴加工不同步进一步恶化了加工性能; 高速加工数控系统更应关注时间参数对加工性能的影响．

Aiming at the significant influence of timing parameters (i. e. sampling period and delay) on the con-touring performance of networked CNC (Computer Numerical Control) systems due to the involved networks,thispaper sets up a networked CNC system model with delay based on the modified Z transformation,and constructs therelationship between timing parameters and the contouring performance index, with the corresponding influence lawsbeing also obtained. The results show that (1) both the delay and its jittering increase the contour errors of multi-axis processing; (2) the sampling period is the primary factor influencing the contouring performance; (3) themulti- axis control actuation asynchrony caused by delay leads to the degradation of contouring performance; and(4) more attention should be paid to the influence of timing parameters on the contouring performance of high-speed networked CNC systems.