Abstract: There is disclosed a system for controlling a plurality of motors including a spindle motor of a machine tool to rotate synchronously at command speeds. The system comprises a numerical control unit for generating as positional commands trains of distributed pulses having frequencies corresponding to commanded speeds of rotation respectively for the motors, positional control feedback circuits respectively for the motors for producing speed command outputs from the trains of distributed pulses and detected signals indicative of positions of the motors, and speed control feedback circuits respectively for the motors for controlling the speed of the motors based on the speed command outputs and detected signals indicative of speeds of rotation of the motors.

Abstract: An operating information input method in a numerical control apparatus which executes prescribed numerical control processing based on numerical control program data and operating information includes steps of designating the start of operating information input displaying, on the screen of a display device, various operating information items (e.g. MODE, HANDLE AXIS, and HANDLE *10) e.g. and selectable items (MDI, AUTO, EDIT, HNDL, JOG, ZRN, HX, HZ) in the form of characters in response to designating the start of inputting operating information positioning a first cursor (CSR) on a line of an operating information item to be input, thereafter positioning a second cursor associated with the operating information item designated by the first cursor, on a line of a prescribed selectable item to identify the desired operating information based on the positions of the first and second cursors.

Abstract: First and second tool control blocks respectively precede and follow a corner on a tool path. A pulse distribution computation based on NC command data in the second block is not executed at the instant that a pulse distribution computation based on NC command data in the first block ends. Rather, a pulse distribution computation based on the NC command data in the second block is performed starting at the instant that a feed speed based on the NC command data in the first block is reduced to a prescribed speed by being decelerated. As a result, the torch of a gas cutting machine or the like will cut the corner portion quickly with a high degree of accuracy and without cutting the corner to an overly rounded shape.

Abstract: In order to permit manual operation under a condition where the axial direction of a tool and the direction of a hole to be machined in a workpiece are held in agreement, the tool of a radius .gamma. is rotated by .theta. in the vertical rotational direction and by .rho. in the horizontal rotational direction in a orthogonal coordinate system and in a spherical coordinate system the origins of which coincide with the center of rotation of the tool. Upon doing so, in the orthogonal coordinates, the position of the front end of the tool becomes X.sub.0 =.gamma. sin .theta..multidot.cos .rho., Y.sub.0 =.gamma. sin .theta..multidot.sin .rho. and Z.sub.0 =.gamma. cos .theta.. Therefore, a train of pulses (Hp) from a manual pulse generator are distributed as X-, Y- and Z-axial components in the proportion to the above values by a manual pulse distribution circuit, and motors for the respective axes are driven through servo circuits by the pulses.

Abstract: A method of checking the rotational frequency of a spindle in a numerically controlled machine tool for rotating the spindle on the basis of a spindle rotational frequency command issued by a numerical control device. An alarm signal is issued when a fluctuation in the actual rotational velocity (AVC) of the spindle falls outside limits (TRV.sub.1) decided by a predetermined allowable percentage of velocity change, or when the actual rotational velocity (AVC) does not attain predetermined velocity limits (TRV.sub.2) even after the passage of a predetermined time period (P) following a change in commanded velocity.

Abstract: A numerical control method for a numerical control device which executes processing based on a machining program composed of multiple items of numerical control command data such as numerical command data and G-code data. Each item of the G-code data is expressed in the form of an alphabetic character G, a numerical value following G, and a code following the numerical value. The method includes inserting the items of G-code data in the machining program at suitable locations, subsequently discriminating the G-code data, and causing the numerical control device to execute processing specified by the discriminated G-code data.

Abstract: The present invention has for its object to make it possible to stop the relative movement of a cutter and a gear blank or change its speed during cutting in a numerical-controlled machine tool for cutting a gear, such as a gear hobbing machine, a gear grinding machine or the like. To perform this, two kinds of pulse distributors, i.e. a synchronization control pulse distributor (152) and a tooth profile forming pulse distributor (153) are provided; the synchronization between the rotation of a cutter (110) and the rotation of a gear blank is provided by the synchronization control pulse distributor (152); and an additional rotation of the rotary shaft of the gear blank necessary for forming the tooth profile of a gear is effected by the tooth profile forming pulse distributor (153).

Abstract: A method and apparatus for controlling a turning operation in which a workpiece, rotated by a spindle, is cut by a cutting tool transported axially of the spindle in synchronization with the rotation thereof. The rotational speed of the spindle is sensed prior to the start of cutting, and the tool position axially of the spindle is corrected prior to the start of cutting based on the sensed rotational speed. Alternatively, once the rotational speed of the spindle has been sensed, a correction based on the sensed speed can be effected in the position at which a signal indicative of one spindle revolution is generated. The signal acts as a start signal to initiate cutting of the workpiece.

Abstract: A system in which the radius of a tool is compensated for in the three-dimensional machining of a workpiece, wherein a tool is offset from a commanded tool path by a distance commensurate with the tool radius.

Abstract: A system for reversing the direction of an electric discharge machine in response to a short-circuit signal. A controller responds to the short circuit signal by generating a command signal with a magnitude greater than a stored error between a commanded value and a number of feedback pulses produced by rotation of a motor which drives the electrode. The sign of the generated command signal is opposite to that of the stored error so that the stored error is converted into a value capable of reversing the direction of the electrode without delay.

Abstract: An acceleration/deceleration circuit for raising or lowering a feed velocity, in order to achieve a commanded velocity, over a prescribed time constant irrespective of the magnitude of a change in velocity. The acceleration/deceleration circuit includes means (301) for computing a traveling distance along each axis every sampling period (T), a first storage section (#1 through #n) for storing n samplings of traveling distance components along each axis, a second storage section SUM for storing results of computation, and an arithmetic section (ADD, ACC, DIV) for performing an operation:.sub..DELTA. Xn-.sub..DELTA. Xo+St.fwdarw.Stwhere .sub..DELTA. Xn represents the latest sampled traveling distance component, .sub..DELTA.

Abstract: A numerical control method, and a numerical control device for subjecting a workpiece to a predetermined machining operation on the basis of a machining program. When a specified signal is generated during a machining operation under the control of the machining program, a subprogram, to which the numerical control device responds to execute processing in accordance with the specified signal, is stored in memory beforehand. Machining in progress under the control of the machining program is interrupted temporarily by the generation of the specified signal. At the same time, the subprogram is read from memory and is utilized in the processing of predetermined process steps. Following such processing, machining under the control of the machining program is resumed from the point of interruption or from an earlier point.

Abstract: Disclosed is a measurement method performed by a numerical control device measurement apparatus having a device for computing and storing the difference between a number of feedback pulses, each of which is generated whenever a movable element moves by a predetermined amount, and a number of command pulses (P.sub.s) generated by a pulse distributor, a motor being controlled in such a manner that said difference approaches zero. Specifically, the measurement method includes counting, by the storage and computing means sensor pulses (MP) generated by a sensor, reading the counted value in the storage and computing device and applying the same to the pulse distributor as a command, computing and storing, by the storage and computing device, the difference between the number of sensor pulses (MP) and the number of distributed pulses (P.sub.

Abstract: A numerical control method for executing numerical control processing using a numerical control unit (102), based on a machining program having plural items of command data recorded on an NC tape (101). Under the numerical control method, numerical control processing is executed based on a succeeding item of command data which has been preread or which has been read after completion of numerical control processing based on an item of preceding command data. An upper limit feed speed (V.sub.L, V.sub.C), based on a workpiece shape commanded by the machining program and on an allowable machining error, is previously determined and stored in registers (RG1, RG2). The magnitude of the upper limit feed speed (V.sub.L, V.sub.C) and the magnitude of an actual feed speed (Vi) is compared, and the actual feed speed is clamped to the upper limit feed speed V.sub.L, V.sub.C, even when Vi exceeds V.sub.L or V.sub.C.

Abstract: Among machining commands, symbols denoting moving directions, and movement data held in correspondence with data numbers are separately stored in a command area (101) and a data area (102), so that when a predetermined machining command, including a data number, has been read out from the command area, the movement data is read out of a memory location corresponding to the data number of this machining command, so as to successively perform predetermined numerical control processing.

Abstract: A numerical control system which includes an automatic programmer and at least one numerical control device interconnected by a cable, in which a numerical control program prepared by the automatic programmer is transferred to the numerical control device. The automatic programmer includes an input unit for entering data, a processor which edits the data for producing a numerical control program, a memory for storing the complicated numerical control program, and a display device which displays a graphic in accordance with the output of the processor. The numerical control device includes a memory for storing the numerical control program, which is transferred from the automatic programmer via the cable.

Abstract: The coordinate values (X, Y, Z) for the position of the front end of a tool and the vector (I, J, K) of the axial direction of the tool are read in from a command tape by a tape reader. Using these values and a tool length l set by a dial or the like, a movement data calculation circuit calculates the orthogonal coordinate values (x, y, z) of the position Q of the center of rotation of the tool and spherical coordinate values (b, c) indicative of the position of the rotational angle of the tool. After these coordinate values are converted into pulses for moving the tool in the respective axial directions by a pulse distribution circuit, servomotors are driven by the pulse signals and through servo circuits so as to move the tool or a table to a desired machining position.

Abstract: A positional error correction system applicable to a numerical control for controlling a machine tool along more than one control axis, such as along X and Y control axes. If the machine tool is to be positionally controlled along the X-axis, the position of the machine tool along the X-axis is corrected by a correction factor which is a function of the position of the machine tool along that axis and the position of the machine tool along the Y-axis, thus providing highly accurate position correction. The position error correction system is not restricted to merely the X and Y axes and can include control of a Z-axis. In such a case the positional correction is performed using a correction factor which is a function of the machine tool position along all three axes.

Abstract: A method and apparatus for controlling the return of a movable element of a machine tool to a predetermined grid point by controlling a movable element drive device in accordance with feedback pulses generated while the drive device is being driven to transport the movable element between grid points. The method includes the steps of specifying a position remote from the predetermined grid point by a distance which is less than the spacing between grid points, computing the deviation between the specified position and the current position of the movable element, positioning the movable element at the specified position by driving the drive device on the basis of the computed deviation and the feedback pulses, and driving the drive device at reduced speed to stop the movable element at the first grid point encountered following the initiation of reduced-speed drive.

Abstract: The present invention pertains to improvements in signal transmitting and receiving equipment for transmitting and receiving signals regarding the M, S and T functions between a numerical controller and a machine tool. Numeric codes (c.sub.l to c.sub.n) that are sent from the NC apparatus to the machine tool are added or combined with a redundant signal (pt) for checking the validity thereof. Only when it is decided that the received codes are valid, based on the added signals, is the machine tool operated. With such an arrangement, even if a parallel transmission system using many signal lines is employed it is possible to offer an NC machine tool which is capable of preventing erroneous operations related to the M, S and T functions, and hence the NC machine tool has high reliability.