A method and apparatus for controlling of the movable parts of a machine tool, by means of a numerical outline - or point - for - point - control system, wherein two parts of the machine brackets independently along a common axis can be moved

摘要

Methods and apparatus relating to either point-to-point or contouring control of the movable members of a machine tool, wherein two or more of such members are movable along a common axis relative to a base. In order to accept end-point commands numerically expressed in part coordinates along the common axis with reference to an origin in fixed relation to a workpiece or part mounted on the first such member, even though the servo controls or actual positioning operations can only act to bring the two members to positions measured in base coordinates with reference to a second origin fixed in relation to the base, a first signaled number representing the desired position of the second member in base coordinates is subtracted from a second signaled number representing the desired position, in part coordinates, for the first member. Such subtraction creates a changeable signaled third number representing the base coordinate positions to which the first member is to be moved under servo control. When the second member is moved, its displacement from one position to the next is added to the aforesaid first and second numbers, so that the third number does not change but the first number does change to provide a numerical representation of the base coordinate position to which the second member will be moved under its servo control.