frequency variation; phase difference signal processing; fuzzy-PID control; frequency signal tracking

When heterogeneous honeycomb materials are cut using ultrasonic techniques, the ultrasonic frequency tends to vary over time, thereby degrading the quality of the machining. This variation can be addressed with a proportional–integral–derivative (PID) controller; however, these controllers perform relatively poorly in fixed parameter tracking scenarios. In contrast, this paper proposes a tracking model that combines fuzzy and PID control.