Abstract: When a read block includes a code for setting a machine coordinate system used for exchanging a tool or the like, it is determined whether a feed rate specifying modes, set by a parameter, is (a) specification by using parameters, (b) specification by a program, or (c) specification by using an external signal input. In mode (a), the rapid traverse speed set for movement according to machine coordinate system or different feed rate set by a parameter is selected and set as feed rate F. In mode (b), a feed rate specified by a program is set as feed rate F. In mode (c), an input signal is converted into a speed which is set as feed rate F. Then the movement command according to the machine coordinate system is executed with this set feed rate F.

Abstract: For outputting an amount of backlash compensation according to the direction of reversal in the reversal motion of the moving axis, three output modes are prepared: (a) a mode in which a preset backlash compensation is outputted all at once, (b) a mode in which backlash compensation is outputted according to distance traveled, and (c) a mode in which backlash compensation is outputted according to time elapsed. It is determined whether the motion of the moving axis has been changed from positive to negative directions or from negative to positive directions, and with this determination result, any one of the above three output modes (a) to (c) is selected.

Abstract: Foreground program execution means executes a program, and outputs movement commands to a control object. Meanwhile, background program execution means checks abnormalities by executing the program, without outputting the movement commands, obtained by executing the program, to the control object. If a program abnormality is detected by the background program execution means, the abnormality is stored in association with the block in which the abnormality is detected. When the program is executed by the foreground program execution means, the program is interrupted at the end of a preceding block for which a program abnormality was stored.

Abstract: When a read block includes a code for setting a machine coordinate system used for exchanging a tool or the like, it is determined whether a feed rate specifying modes, set by a parameter, is (a) specification by using parameters, (b) specification by a program, or (c) specification by using an external signal input. In mode (a), the rapid traverse speed set for movement according to machine coordinate system or different feed rate set by a parameter is selected and set as feed rate F. In mode (b), a feed rate specified by a program is set as feed rate F. In mode (c), an input signal is converted into a speed which is set as feed rate F. Then the movement command according to the machine coordinate system is executed with this set feed rate F.

Abstract: For outputting an amount of backlash compensation according to the direction of reversal in the reversal motion of the moving axis, three output modes are prepared: (a) a mode in which a preset backlash compensation is outputted all at once, (b) a mode in which backlash compensation is outputted according to distance traveled, and (c) a mode in which backlash compensation is outputted according to time elapsed. It is determined whether the motion of the moving axis has been changed from positive to negative directions or from negative to positive directions, and with this determination result, any one of the above three output modes (a) to (c) is selected.

Abstract: Foreground program execution means executes a program, and outputs movement commands to a control object. Meanwhile, background program execution means checks abnormalities by executing the program, without outputting the movement commands, obtained by executing the program, to the control object. If a program abnormality is detected by the background program execution means, the abnormality is stored in association with the block in which the abnormality is detected. When the program is executed by the foreground program execution means, the program is interrupted at the end of a preceding block for which a program abnormality was stored.

Abstract: A moving path for which an interpolation instruction is given is a free curve expressed by a vector P(k). This curve is divided at predetermined cycles, and tangential vectors P' (k.sub.1) and P' (k.sub.2) at the start point and end point of each divided block are calculated. From these data and an instructed velocity F, an acceleration vector in the corresponding block is calculated. If each axial component of the calculated acceleration vector exceeds an acceleration limiting value set for each axis in advance, the instructed velocity F for the block is lowered to a value at which the axial component does not exceed the acceleration limiting value.

Abstract: A free-form curve interpolation method and device is provided for smoothly interconnecting curves using a non-uniform rational B-spline (NURBS) curve representation. This ability to interconnect free-form curves is important when machine parts of small dimensions or complex configuration. This is accomplished by a preprocessing calculation unit reads NC programs including an interpolation command of a NURBS curve expressed by a function using a parameter t as a variable, and calculates a distance .DELTA.L to move during an interpolation period T. A parameter change calculation unit calculates a change .DELTA.t in the parameter t brought on when moving by the distance .DELTA.L, on the basis of a current position specified by a current value t.sub.i of the parameter t. A movement amount calculation unit calculates a position when the value of parameter t is t.sub.i +.DELTA.t, by a defining formula of the NURBS curve.

Abstract: A three-dimensional cutter compensation system provides cutter compensation for machining a workpiece with a cutter having a round edge and an axis which is tiltable in any optional direction in three-dimensional space. The three-dimensional cutter compensation system includes a cutter direction vector calculating unit for calculating a cutter direction vector from present position control axes. The control axes control the tilt of the cutter. A cutter offset memory stores a radius of the cutter and a radius of an arc of the edge of the cutter while a programmed path calculating unit calculates a programmed path commanded by a machining program. A cutter compensation vector calculating unit calculates a cutter compensation vector from the cutter direction vector, the radius of the cutter and the radius of the arc of the edge of the cutter, and the programmed path. The cutter is then shifted in response to the cutter compensation vector.

Abstract: A speed control method for a numerical control apparatus of a machine tool which includes a rotational axis or axes changing a tool angle relative to a workpiece. The method obtains a distributive shift amount of each rotational axis, at every predetermined period, on the basis of positional data of each rotational axis with respect to start and end points of a shift command and a commanded shift speed; obtains, at every predetermined period, a positional deviation of a tip of the machine tool in a direction of each linear shift axis with reference to the rotational axis, based on a difference between a rotational position of the rotational axis in a next cycle and a rotational position of the rotational axis in a present cycle; for each linear shift axis, adds the positional deviation to the corresponding distributive shift amount, and outputs a resultant value as a corrected distributive shift amount for each linear shift axis; and for each rotational axis, outputs the obtained distributive shift amount.

Abstract: A computerized numerical control apparatus for switching an acceleration constant for acceleration/deceleration prior to interpolation in accordance with the kind of an axis, in which an acceleration/deceleration prior to interpolation unit subjects a feed speed to an acceleration/deceleration process based on an acceleration constant designated by an acceleration constant switching unit. The feed speed subjected to the acceleration/deceleration process is transferred to an interpolation unit. The interpolation unit determines distribution pulses X.sub.p, Y.sub.p, Z.sub.p based on the speed data and movement data thereof. The distribution pulses are applied to an X-axis control unit and the like, respectively, and output to the respective axis motors M.sub.x and the like to execute the drive control thereof.

Abstract: Disclosed is a numerical control apparatus for controlling a chopping operation of a tool used in a grinding machine and the like. A programmed instruction value calculation circuit (2) outputs an upper dead point instruction (Zu) and a lower dead point instruction (Zl), a correction value calculation circuit (3) calculates and outputs correction values (.DELTA.Zu, .DELTA.Zl), and a chopping instruction calculation circuit (4) outputs a chopping control output to a manual control circuit (6) based on these instructions and correction values to operate a servo motor. When an instruction value (Zi) is input from a manual pulse generator (5) to the chopping instruction calculation circuit (4), the chopping is effected while continuously changing the upper and lower dead points, thereby enabling an operator to easily adjust the upper and lower dead points.

Abstract: A numerical control method is provided, which is capable of compensating for a response delay of a servo system to command pulses to thereby make it possible to repetitively effect reciprocal movement of a controlling object at a high speed over the entirety between target positions inclusive of these positions, without the need of increasing a time period for execution of a desired operation.