Frequency tracking algorithm of ultrasonic drill based on fuzzy control: Design and experiments

The ultrasonic drill transforms high-frequency electrical energy into mechanical vibrations of the same frequency, enabling the drill bit to fragment rock with minimal drilling force. This characteristic is especially beneficial for anchoring operations on small celestial bodies with low gravity. Focusing on the drive of the ultrasonic drill, the resonant control algorithm for the ultrasonic drill is investigated. An equivalent circuit model of the ultrasonic drill transducer is established, and based on this model, the impedance characteristics, load characteristics, and temperature characteristics of the transducer are studied. According to the operational characteristics of the ultrasonic drill, a resonant frequency identification algorithm and a fuzzy control-based resonant frequency tracking algorithm are developed, and the actual control performance is comparatively analyzed. Finally, drilling tests on sandstone samples are conducted under the resonant control algorithm. The experimental results indicate that the designed resonant control algorithm can achieve stable and efficient driving of the ultrasonic drill, with a drilling rate reaching 50 mm/min.