Modeling and Experimental Analysis for Worktable Dynamic Characteristics of CNC Gear Hobbing Machine

To reveal the dynamic characteristics of worktable axle of CNC gear hobbing machine due to interrupted cutting, the servo control system of the worktable is analyzed. According to electromechanical principle and mechanical dynamic principle, every component model of the servo control system is constructed to derive an overall servo control system model of the rotary table. Considering the nonlinear Stribeck friction factor, a simulation model of the worktable servo system is established by Simulink. The effects of different position and speed command frequency variation on the dynamic response of the workpiece axis servo system are discussed and the servo dynamic characteristics reflecting the location and speed of the worktable axle are obtained. When the servo system of the rotary table runs at low speed, the “flat top” exists in the position tracking, and the “dead zone” exists in the speed tracking. The position and speed following rate of the servo system of the rotary worktable decrease with the increasing given command frequency, especially when the instruction frequency increases to 31 Hz, the following rate is less than 10%. The model accuracy is verified by online test of the worktable, the experimental response curves coincide with the simulated ones well at the same command frequency.