An intelligent monitor system of otologic drill to prevent drill bit entangling with the cotton

Otologic drill is an important ear surgical instrument and used to mill temporal bone. The cotton which is used to stop bleeding may be entangled with the drill and whirl. The rotary cotton can damage the tissues, such as nerves and cochlea. An intelligent control device has been designed to help doctors to operate the drill and prevent the cotton from causing damage to human. The intelligent control system installs current sensor, force sensor, computer and reverse braking device. It could use information fusion technique to recognize drilling fault and brake in 0.2 seconds. Its intelligent recognition algorithm is composed of a characteristic curve and an adaptive filter. The characteristic curve is designed according to the mathematical model of the cutting force. The curve calculated by the data of current and force is sensitive to drilling fault. In order to modify the error of model and improve recognition rate, an adaptive filter is designed to eliminate interferences in the characteristic curve. The adaptive filter could fuse multi-sensor information and take full advantage of the difference between interferences and drilling faults to suppress interferences. The drilling fault can be recognized by calculating the increment of filtering result. The system has been tested. The rate of identifying cotton swab entanglement is 95%. Only 0.5% tests of the normal drilling are identified as drilling faults.