Fig. 1. Multi-channel cutter wear detection sensing system

Fig. 2. Theoretical simulation of reflectivity. (a) Peak reflectivity curves under different coupling coefficients; (b) reflectance spectra under different grating lengths when k=0.35 mm^-1

Fig. 3. Principle diagram of wear detection

Fig. 4. Diagram of packaging of wear sensor

Fig. 5. Wear data diagrams. (a) Demodulation of wear curve; (b) error analysis curve