The Analysis And Research Of CNC Rotary Table Feed System

The CNC machine tool rotary table is the key components of CNC machine tools which can achieve the rotary motion, and its performance could direct affects precision and stability of the CNC machine. With the performance upgrading of the CNC machine, its transmission accuracy rotary table, response speed and processing stability put forward a higher requirement. The CNC machine tool rotary table dynamic characteristics depend largely on the performance of its feed system, the CNC machine tool rotary table feed system is composed by mechanical drive system and servo drive system.The mechanical feed system is consist by the multi-stage gear and worm gear, and the main feature vibration of the transmission system is torsional vibration. The torsional vibration of gear system not only makes rotary table processing stability deteriorates, but also shorten the fatigue life of the gear transmission system. The Servo system is an automatic control system which regards position and velocity as control object, and the response speed and stability of rotary table is largely determined by the performance of servo system. The main form of servo control system is PID loop control. Also the PID controller parameters are a vital role to the performance of the servo system.The major work in this thesis which regard the gear transmission and servo drive system as the research object are listed as follow:1. Established the seven degrees of freedom torsional vibration dynamics model of the rotary table gear transmission system which according to the Lagrange equation;2. Obtained natural frequency and vibration model of gear transmission system by using the transfer matrix method;3. Using the direct integration newmark-β analyzed the dynamic response analysis of the gear transmission system which under stiffness and error excitation;4. Designed and setting the rotary table servo system, optimized the PID controller parameters by using the simplex method which under three different optimization criteria. The results demonstrated that the stability and the response speed of the servo system are improved by using the GISE optimization criteria.