Development of a Percussive Ultrasonic Drill Driver

Compared with the conventional drill driven by magnetic motors, percussive ultrasonic drill (PUD) shows advantages of small size, low power, low axial load, and lubrication free, making it available for the extraterrestrial rock sampling, especially for the minor planet with a weak gravitational field. The influence of the environment, load and aging of the components cause the resonance frequency of the PUD to drift, which causes the drilling efficiency of the PUD decreases drastically. During the PUD drilling rocks, the load imposed on the transducer is fickle. Though, the conventional frequency tracking control which tracking frequency by locking fixed phase does not perform well for the PUD. This paper presents a novel driving approach for the PUD, including the working principle of the PUD and a detailed design approach for the PUD driver. A driving circuit and a control algorithm were developed successfully. The experimental results show that the driver can drive the PUD effectively and make the drill work stably near the resonant frequency under different conditions.