초록 ▼

The initial contact of a rotating milling tool to a workpiece is detected in the presence of spurious noise spikes by digitally processing samples of a preprocessed vibration signal concurrently through basic tool touch detection logic and milling tool touch detection enhancement logic, and generati

The initial contact of a rotating milling tool to a workpiece is detected in the presence of spurious noise spikes by digitally processing samples of a preprocessed vibration signal concurrently through basic tool touch detection logic and milling tool touch detection enhancement logic, and generating a touch indication if either logic set is satisfied. The basic logic detects a continuously increasing signal level higher than a threshold set above background noise. The milling logic detects an above-threshold signal sample and sets up an acceptance window about the expected time of contact of the next cutter. Tool touch is declared when an above-threshold signal occurs during the window; the milling logic is reset by a noise spike in the interval before the window starts. The basic logic detects tool touch in a dense spiky noise situation.

대표청구항 ▼

A method of acoustically detecting the initial contact of a workpiece and rotating milling tool having one or more cutters comprising: sensing vibrations and generating a vibration signal as said milling tool slowly toward said workpiece and makes light rubbing contact; preprocessing said signal in

A method of acoustically detecting the initial contact of a workpiece and rotating milling tool having one or more cutters comprising: sensing vibrations and generating a vibration signal as said milling tool slowly toward said workpiece and makes light rubbing contact; preprocessing said signal in an analog channel to restrict the output waveform to a specific band of frequencies and prepare the signal for sampling and analog-to-digital conversion; digitally processing signal samples of said analog output waveform concurrently through basic tool touch detection logic and milling tool touch detection enhancement logic, and generating a tool touch indication when either set of detection logic is satisfied; said basic tool touch logic comprising checking each sample amplitude against a threshold set above continuous background noise peaks, and generating said tool touch indication upon detecting a predetermined number of positive slope above-threshold signal samples; said milling tool touch logic comprising entering into a touch suspicion mode upon detecting one above-threshold signal sample and setting up an acceptance time window about the expected time of contact of the next cutter and said workpiece, and generating said tool touch indication upon detecting an above-threshold signal sample in said acceptance window.