A Practical Servo Control Algorithm for Rotary WorkTable of CNC Gear Hobbing Machine Based on Active Disturbance Rejection Control

This paper proposes a rotary worktable servo system control model based on active disturbance rejection control (ADRC) to address the total uncertain disturbances in the rotary worktable servo control system of a CNC gear hobbing machine. These uncertain disturbances are driven by factors such as changes in the parameters of the servo motor, external friction and vibrations caused by the roll-cutting force. A simulation model for the proposed ADRC controller is established based on the LuGre friction model. The given signal interference and frictional force in the servo system are taken as the disturbance quantities considered in the simulation model as the basis for state observations. The simulation results indicate that compared with traditional PID control, the proposed controller has a better inhibiting effect on non-linear friction. Meanwhile, it also possesses a high response speed, small steady-state errors and good anti-interference capabilities. Finally, the validity and feasibility of the proposed control strategy are proven through an idle running experiment and a gear cutting experiment using a gear hobbing machine. In particular, the speed tracking accuracy of the rotary worktable under the vibration disturbances from the main shaft cutting force is effectively improved.