基于声信号处理的骨铣削状态监测

Bone milling condition monitoring based on sound signal processing

考虑声信号能提供关于切削刀具及组织接触状态信息,通过采集、分析在椎板切除术中产生的声信号实现铣削状态监测。建立微分方程描述椎板受切削力作用的受迫振动,证明振幅随骨厚度减少而增大。利用离散小波变换从采集的声压信号中提取主轴频率整数次谐波分量,通过计算特殊尺度的小波能量积判断铣削状态。用所提状态监测方法对猪脊柱进行铣削实验,并获得验证。结果表明,椎板将要被穿透时小波能量积会显著增大。

In consideration of that the sound can provide useful informations about tool-tissue contact, the condition monitoring was realized by acquiring and analyzing the sound signal during laminectomy surgery.A differential equation was presented to describe the vertebral lamina vibration excited by the cutting force,and it is proved that the vibration amplitude will increase as the thickness of the bone decreases.Discrete wavelet transform was performed to extract the harmonic components whose frequencies are integer multiples of spindle frequency from the sound pressure signal,the products of wavelet energy at some special scales were calculated to judge the milling status.The proposed condition monitoring method was experimentally verified through the milling operation in porcine spines,and the results indicate that the product of wavelet energy will increase significantly when the vertebral lamina is going to be penetrated.