State recognition of bone drilling with audio signal in Robotic Orthopedics Surgery System

Bone drilling is an important and difficult process in orthopedic surgeries. To detect the drilling state of a Robotic Orthopedic Surgery System (ROSS) in real-time, a state recognition method based on audio signals, the Acoustic Emission (AE) signals generated in drilling process, is proposed in this paper. By an analysis via power spectral density of the AE signals, an appropriate frequency band is selected for state recognition. The Exponential Mean Amplitude (EMA) and the Hurst Exponent (HE) are used to illustrate the energy characteristics and stability of the AE signals in the chosen frequency band, respectively. The recognition algorithm combines the two different features is performed on a embedded device in the experiments. Finally, the experiments are carried out to demonstrate the effectiveness of the proposed drilling state recognition method.