Powerlasers Ltd.

Grant Kinsman

Walter W Duley

There is provided a method and apparatus for controlling, in real-time, processing variables in laser processing of materials using fuzzy logic control procedures by embedding expertise in the form of a rule base within a fuzzy logic controller. The method uses a visible light detector as part of the control loop to detect light from the laser-material interaction zone. The light is processed to extract spatial information on the size of the interaction zone and in one aspect determines the number of bright pixels above a pre-defined number which effectively gives the spatial extent or area of the visible light emitted from the interaction zone. From this elemental processing two system input variables are obtained, namely the current number of bright pixels, #BP, and the change in this count since the last calculation, .DELTA.BP. These input variables are input to the fuzzy logic controller for an inference pass with the output being used to control a laser processing variable such as laser power, laser intensity and process speed. More than two system input variables may be used to provide greater stability. Integrating the fuzzy logic controller with the image processor provides control of penetration welding of steel plate at a rate of 28 Hz.

Method and apparatus for real-time control of laser processing of

There is provided a method and apparatus for controlling, in real-time, processing variables in laser processing of materials using fuzzy logic control procedures by embedding expertise in the form of a rule base within a fuzzy logic controller. The method uses a visible light detector as part of the control loop to detect light from the laser-material interaction zone. The light is processed to extract spatial information on the size of the interaction zone and in one aspect determines the number of bright pixels above a pre-defined number which effectively gives the spatial extent or area of the visible light emitted from the interaction zone. From this elemental processing two system input variables are obtained, namely the current number of bright pixels, #BP, and the change in this count since the last calculation, .DELTA.BP. These Input variables are input to the fuzzy logic controller for an inference pass with the output being used to control a laser processing variable such as laser power, laser intensity and process speed. More than two system input variables may be used to provide greater stability, integrating the fuzzy logic controller with the image processor provides control of penetration welding of steel plate at a rate of 28 Hz.

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Waterloo, Canada

Grant Kinsman