Patent ID: 6566835
Filing Date: 2003-05-20
Classification: G05B

Abstract:
A method of controlling a numerically controlled machine tool having a plurality of feed shafts of three orthogonal X-, Y-, and Z-axes or at least one of rotary shafts of A-, B- and C-axes in addition to a plurality of feed shafts of three orthogonal X-, Y-, and Z-axes, characterized in that the method comprises the steps of:taking numerical controlling program data from a reading and interpreting unit provided in a numerically controlling device to execute the program data in a movement command distribution controlling unit and a servo control unit; estimating an appropriate torque or electric current command corresponding to the changes in frictional force in the feed mechanisms of the respective feed shafts or in the weight of a workpiece based on the results of execution of the numerically controlling program data outputted from the servo control unit; outputting the estimated appropriate torque or electric current command to motor drive means of the feed shafts; and driving feed motors by the appropriate torque or electric current command corresponding to the changes in frictional force in the feed mechanisms of the respective feed shafts or in the weight of a workpiece.