Open loop control apparatus and associated method for cutting sheet

Abstract

An expert system containing a built-in application knowledge is used with a controllable cutting system to automatically seek an optimal feed rate during cutting in response to various of a number of possible changing system cutting parameters wherein a programmable controller defines and specifies a preset configuration file defining the specific cutting system control parameters for directing the operation of the cutting system in accordance with a contour defining a path be followed by a cutter carried by the cutting system and which cutter is moved in an X, Y and C coordinate space across the cutting surface of the cutting system. The X, Y and C axes motors are driven with a commanded current to move the cutter with a velocity defined in the configuration file. The cutting force developed by the cutter is determined at predetermined portions of the contour to determine the toughness of the spread and the actual cutting force is compared to the optimal cutting force with the feed rate being adjusted to increase when the actual force is below the expected force and decrease when the actual force is above the expected force and to shut down the cutting system to rebuilt the contours when the actual force exceeds the expected force by a predetermined magnitude. The feed rate is computed for the contour taking into account information concerning the toughness of the material being cut, the sharpened data, the vacuum level, the knife motor current and the knife velocity.