在数控伺服系统中，当系统参数发生变化或者受到外界干扰时，采用PID控制容易导致过大的超调甚至引起震荡，从而使系统的动静态性能变差。本文提出一种模糊PID控制器，它结合了PID控制和模糊控制的优点，具有较好的自适应和抗干扰能力。以本研究所研制的数控高速铣齿机Z轴位置伺服系统为研究对象，在Matlab中分别采用PID和模糊PID控制进行仿真。结果表明，模糊PID控制器具有较强的鲁棒性和抗干扰能力，更能满足数控伺服系统的性能要求。关键字：模糊PID控制器；交流伺服系统；位置控制；MATLAB仿真Simulation on CNC servo system based on fuzzy theory SHI Li-ting, HUANG Xiao-diao , HONG Rong-jing （Mechanical and Power Engineering Department of Nanjing University of Technology, Nanjing Jiangsu, 210009, China）Abstract: Variation of the system parameters and external disturbances always happen in the CNC servo system. With a PID controller, it may lead to large overshoot even oscillation, then the steady state and dynamic state performance will be worse. In this paper, a fuzzy-PID controller was proposed,and it incorporated the advantages of PID control and fuzzy control，which had good performance of adaptation and disturbance rejection. Based on the z-axis position servo system of a high-speed milling machine researched on our institute, simulations were carried out in Matlab with PID controller and fuzzy-PID controller. The results show that the system has stronger robustness and disturbance rejection with the latter, which can meet the performance requirements of the CNC servo system better.Keywords: Fuzzy-PID controller; AC-servo system; Position control; MATLAB simulation