Abstract: A reference-point return method for a numerical control system. When a return is made to a reference point, a numerical control unit (21) reads an absolute position of a motor (23) within one revolution thereof from an absolute position detector (24), obtains a distance B from a predetermined motor point (a grid point) to the absolute position that has been read, and initially sets the distance B as a command position REF.sub.n from the grid point. Thereafter, the numerical control unit (21) outputs a move command value .DELTA.R.sub.n to a digital servo-circuit (22) every predetermined time .DELTA.T, updates a commanded position REF.sub.n in accordance with the equationREF.sub.n +.DELTA.R.sub.n .fwdarw.REF.sub.nobtains REF.sub.n after a deceleration limit switch (25) is depressed, and outputs (N-REF.sub.n) to the digital servo-circuit (22) as a final commanded traveling distance .DELTA.R.sub.n to return the movable element to a reference-point position set at a predetermined grid point.

Abstract: A spindle orientation control apparatus according to the invention provides a spindle (4) for which a magnetic sensor senses the spindle and outputs stopping-position proximity (LS) signal and a stopping position determination (MS). The spindle (4) is coupled via gear or belt (5) to a spindle motor (2) wherein the spindle is controlled to stop at a fixed position based on a velocity command conforming to velocity of the spindle motor (4). Velocity pulses for detecting the rotational velocity of the motor can be employed as position pulses. A velocity command value (VCMD) can be reduced by an amount corresponding to a number of fed back velocity pulses a. The velocity value is clamped at a predetermined level when the velocity command value of the spindle attains a predetermined level until a final changeover. The final the spindle changeover for making equal stop-position decision signal (MS) signal and the velocity command value when an edge of the stop-position proximity signal (LS) signal is detected.

Abstract: Disclosed is a synchronous control system for effecting a synchronous and superimposed operation among different channels of a multi-channel-control machine tool. A follow-up error amount (.epsilon.3) of a servomotor responsive to a superimposing instruction is simulated, a difference is determined by subtracting the follow-up error amount (.epsilon.3) to the superimposing instruction from a follow-up error amount (.epsilon.2) of a servomotor for a superimposed operation axis (Z2) and the difference is compared with a follow-up error amount (.epsilon.1) of a servomotor for a synchronous operation axis (Z1) to produce an alarm when the comparison indicates the operation of the servomotors is synchronized and superimposed.With this arrangement, a synchronous error can be checked when a superimposed operation of the servomotors is effected.

Abstract: A motor drive system used with industrial robots, processing machines, and the like comprising an external interface part ready for connecting a plurality of kinds of host controllers generating a command signal; a sensor interface part to which a motor rotation detecting sensor is connected; a main control part operating for feedback control of a motor according to signals provided by way of the interfaces; and a power amplification part for feeding a current to motor coils according to a control signal from the main control part and wherein the external interface part, the sensor interface part, the main control part, and the power amplification part are separate and modularized as cards. Advantageously, the various controllers, sensors and power systems are changeable to flexibly meet different user requirements.

Abstract: A numerical control system controls a plurality of axes with a plurality of channels (10, 20, 30). When a machining program for a first channel (10) is interrupted after a single block in response to a single block signal (6), the feeding of commands of a machining program for other channels (20, 30) is held. The machining programs are thereby executed in synchronism with each other. The machining processes are prevented from being unbalanced, and machining interference is avoided.

Abstract: When a spindle (10) of a machine tool is rotated and moved relative to a workpiece linearly along an axis (Z) thereof during a machining process such as screw cutting, a spindle servomotor (12) and a feed servomotor (22), each of which is the primary drive, must be rotated synchronously. In general, the spindle servomotor directly drives the spindle without a reduction gear, and the feed servomotor feeds a spindle head (18) through reduction gears (26, 28). Therefore, in general, the synchronous work is controlled in accordance with an acceleration and deceleration capacity of the spindle servomotor. Consequently, the spindle servomotor is rotated along the torque limit curve line (L1, L2) to drive the spindle, to thereby effect the synchronous work at a high efficiency.

Abstract: The present invention discloses a method of loading a control program for a numerical control apparatus, wherein the control program is composed of a plurality of load modules. Each module contains a judgment codes, such as a version number, at the head portion thereof, and is stored in a read/write operation enabling memory, so that each of the judgment codes can be compared with a corresponding judgment code received from an external apparatus by a judgment code comparing means. When the comparison detects different judgment codes, transmission of the new load module corresponding to the discorded judgment codes requested by a modified load module requesting means. Only the substantive portion of the load modules corresponding to the discorded judgment codes received through the comparing means and requesting means need be loaded onto the memory by way of a load means.

Abstract: A microcomputer 1 servo controls a rotational speed of a capstan motor 10 in a VTR in a digital manner. A value of a timer counter 6 is stored in an ICR 7 at a timing of each edge of FG signal pulses generated as the capstan motor rotates. Thereafter, in the microcomputer 1, a FG interrupt processing is carried out corresponding to the value of ICR 7. More specifically, the microcomputer 1 alternately measures a first period from a rise of one pulse of the FG signal to a rise of a subsequent pulse thereof and a second period from a fall of one pulse to a fall of a subsequent pulse to determine an amplitude of a speed error signal based on these periods. Therefore, a sampling frequency for the digital servo control can be double that of a prior art.

Abstract: A control device for an industrial machine comprising a numerical control device and a programmable controller, the numerical control device comprising: a data processing section essentially comprising a memory and a central processing unit, for analyzing and operating input numerical data, outputs of the data processing section being used for performing numerical control of a machine to be controlled and of rotation of a spindle of the machine; a gear ratio data memory for storing gear ratio data of gears through which a spindle motor is coupled to a spindle head holding a tool, the gear ratio data being applied to the gear ratio data memory through a bus from the programmable controller adapted to perform sequence control of the machine; and synchronous operation controller for calculating actual speed of rotation of the tool through operation using the gear ratio data and a feedback signal of the spindle motor, and performing synchronous operation control of the tool and a feed shaft.

Abstract: A numerical control (NC) apparatus according to the invention provides a command execution function in which a movement command and an operation command are output from an NC tape as NC commands of the same block. A movement completion signal is formed at the moment movement of a tool based on the movement command ends, thereby designating an operation on a machine side based on the operation command. The arrangement is such that a pseudo-signal (DEN.A), which includes a parameter element that can be designated by a program, and an original movement completion signal (DEN.B) can be selected as movement completion signals.

Abstract: A numerical control apparatus according to the invention has a mode designating interface for deciding a control mode and an interface which receives position and velocity commands, these interfaces being interposed between the apparatus and a servo-processor. A mode for controlling the servomotor is automatically decided internally of the numerical control apparatus. Changeover is possible in which the servomotor is used as a motor for positional control or in order to control rotational velocity in the manner of a spindle motor to achieve continuous rotation.

Abstract: An improvement applicable to a multi-axis numerically controlled machine tool for the purpose to enable the means small in capacity. A numerically controlled machine tool provided with plural axes and which is driven by plural driving motors (SP(n)) each of which is attached by an angular position sensor (POS(n)) is provided with (a) a plurality of numerical controller (CNC(n)) each of which is provided with a programmable controller (PMC(n)) for controlling the plural driving motors (SP(n)) in response to external numerical information, and (b) a numerical controller changing-over network (COC) having plural changing-over circuits (COS(n)) for connecting each of the selected ones of the plural angular position sensors (POS(n)) and of the controllers of the driving motors and the corresponding each of the selected ones of the plural numerical controllers (CNC(n)), in response to the changing-over signal (CO) generated by the plural programmable controllers (PMC(n)).

Abstract: A numerical control apparatus for machining non-circular workpieces such as a cam and the like has been disclosed. The cam and the like are used in changing the operation from rotational to linear motion. In designing the shape of the cam and the like, lift data prescribing the relationship between the rotational and linear motions is used. The lift data is given by the position sequence on the linear motion corresponding to a number of discrete rotational angles. Also, the tolerance of the positions is given from a functional aspect. The lift data is converted into profile data prescribing the shape of the cam and the like after being smoothed within the tolerance by a regression analysis, and machining of the non-circular workpieces is effected according to the profile data.

Abstract: A numerical control method makes it possible to perform machining of a workpiece at a high speed with a desired accuracy. After start of pulse distribution, a determination is made as to whether or not both a block being executed and a next block of an NC program relate to a cutting command (steps S12 and S13). An in-position value (A, B), corresponding to the determination result, is then stored in a register (C). In the case of three control axes, when the deviations (.epsilon.x, .epsilon.y, .epsilon.z) between target moving amounts and actual moving amounts for the three control axes are less than the value stored in the register (C), positioning control for the present block is completed, and the execution for the next block is started (S10). This permits variable setting of the desired positioning accuracy to be carried out. The method is applicable for any number of control axes.

Abstract: Expert knowledge regarding investigation of the causes of various failures, and knowledge for extracting DI/DO information (IOD), which is exchanged by an NC unit (11) and a machine tool (13), as well as information (ITD) internally of the NC unit, is stored in a knowledge base (IB). When the contents of a failure are entered from an alarm detector (11g) upon occurrence of the failure, a reasoning mechanism (ADPR) uses the expert knowledge conforming to the failure to automatically extract the DI/DO information and information internally of the NC unit (IOD, ITB), ascertains actually occurring phenomena based on this information, recognizes the cause of the failure from these pheonomena, and displays the cause of the failure and a method of dealing with it.

Abstract: NC data for grooving are created by inputting a groove shape (GR) which lies on a three-dimensional curved surface as well as a groove-depth specifying curve (GRC) which indicates a relationship between a distance d from one end and groove depth hk of a point at this distance, obtaining the distance dk from one end of the groove-depth specifying curve (GRC) in accordance withdk=lk.multidot.Lj/Liwhere Li represents the total length of the groove shape, lk the distance from one end of the groove shape and Lj the total length of the groove-depth specifying curve (GRC), obtaining, from the groove-depth specifying curve, the depth hk at the distance dk from the abovementioned one end, and adopting the groove depth hk as groove depth of a point at the distance lk from the one end of the groove shape (GR).

Abstract: An improvement in a numerical control apparatus for controlling a threading operation with a tap. A numerical control apparatus of the present invention which is simple in construction and needs no dummy mechanism such as a floating tapper; and which minimizes the drift of the tap in the bottom of a tapped hole by an instruction to a feed shaft which switches an acceleration or deceleration time constant, and a simultaneous instruction to a spindle device which controls the position of the spindle device. Thus, the machining precision of the bottom of the tapped hole is improved, and a high-speed tapping operation is possible. Furthermore, the numerical control device also is capable of preventing the tap and the threaded portion machined by the tap from being damaged upon an occurrence of an abnormal condition by an instruction from the removing control unit.

Abstract: An involute interpolation method is provided for machining operations in a numerical control apparatus, in which a rotational direction of an involute curve, a center position of a base circle (C), and a radius (R) of the base circle (C) are instructed, and an interpolation is performed with respect to an involute curve having a start point (P.sub.s) on a first involute curve (IC1) and an end point (P.sub.e) on a second involute curve (IC2). According to such a method, machining operations can be done by the use of a specifically configured involute curve which is distinct from the two involute curves.

Abstract: A mirror control system for electrically powered and positioned mirrors (FIG. 1) of the "memory" type for, for example, moving an automotive side view mirror from its current position to a desired "memory" position, and a special algorithm therefor (FIG. 2), which initially moves the mirror toward the final, desired position at a forty-five (45.degree.) degree angle to the vertical and horizontal axes (NE, NW, SW or SE; FIG. 6), for a mirror whose two directional motors have equal speeds (X=Y). If no obstruction (e.g., the mirror's edge) is encountered (FIG. 3), the mirror is moved by both motors until either the vertical or horizontal axis of the final position is encountered, at which axis intersection point the mirror is moved by only the appropriate one of the motors until the final point along the remaining axis is reached; this is the "normal" mode of the algorithm. However, if an obstruction is encountered (left side of FIG. 2; FIGS. 4 and 5), the mirror is moved at a 45.degree.

Abstract: A method of controlling a side support device which is provided in a seat for a vehicle such as an automobile and the like. In the method, an arbitrary support position can be set manually by driving and controlling a motor by means of a manual switch operation. Also, a closed position and an open position which are respectively present close to the arbitrary support position can be respectively set with one touch automatically by driving and controlling the motor by means of an automatic switch operation.

Abstract: A side support control device for use in a vehicle seat in which by an occupant's switch operation a motor is driven to thereby control the operation of a side support so as to prevent the occupant from losing his or her sitting position. In the control device, the number of rotations of the motor to move the side support is detected by a rotation sensor, the detected number of counts is stored in a counter memory in link with the switch operation, and the amounts of opening and closing of the side support can be adjusted quickly and easily by switch operations.

Abstract: An emergency stop control circuit of a numerically controlled machine tool for controlling emergency stop signals. A relay circuit (1) is provided with input terminals connected to an emergency stop button (22), an overload switch (33), and overtravel switches (34, 35), which are the sources of all emergency stop signals generated by the numerically controlled machine tool. The relay circuit is also provided with output terminals, i.e., contacts (2a, 2b, 2c), connected as necessary to various units including for example, a numerical control apparatus, a servo amplifier, and a spindle amplifier. Accordingly, an emergency stop control circuit requiring only simple connections can be provided. This eliminates the need for a complicated wiring operation.

Abstract: The invention relates to a method of creating NC data for machining the interior of an area. The method includes displaying, on a graphic display unit (106), contours (CNT1, CNT2) inputted in order to specify the area (AR.sub.M), recognizing the area (AR.sub.M), which is designated by a graphic cursor by manipulation of a tablet (108) and painting the interior of the area in a predetermined color, subsequently removing the paint in a linear area (AR.sub.1), having a width equivalent to a width of a tool, which connects a machining starting point (P.sub.S) and a machining end point (P.sub.E) designated by the graphic cursor, adopting the machining end point as the next machining starting point, thereafter inputting machining end points in succession, and creating NC data for machining the interior of the area (AR.sub.M) by traversing a finally designated machining starting point and machining end point while moving the tool linearly.

Abstract: A system for controlling a robot includes a control portion (7) for supplying a control signal to and receiving a control signal from a servo unit (6) for carrying out a signal supply and a signal feedback to an electric motor (5) for driving a shaft executing a Z-axis linear motion, and threshold value supply portion (8) for supplying a threshold value to the control portion. Based on a comparison between a motor torque instruction value and a threshold value supplied from the threshold value supplying portion, an alarm is delivered and the process subsequently proceeds to a step of dealing with an abnormal condition when said motor torque instruction value becomes greater than a predetermined threshold value.

Abstract: The designated speeds of a plurality of blocks are read beforehand, deceleration start positions are calculated to maintain the servo system at a speed below the designated speeds of the blocks read beforehand at the start positions of the previously read blocks, and the servo system is decelerated from the calculated deceleration start positions, whereby the servo system speed is kept below the designated speeds of all of the blocks and the deceleration of the speed of the servo system is controlled with a high degree of accuracy.

Abstract: A hybrid sample rate servo motor employing rate feedback compensation is disclosed. The system employs a shaft encoder having a predetermined resolution to provide position data which are pulses indicating the shaft has moved another resolution unit. Under high motor velocity conditions the rate compensation feedback loop is operated at a conventional constant sample rate. Under low velocity conditions, the sample rate at which the rate compensation feedback loop is operated is modified so that rate samples are taken and calculated only when new position data are available from the motor encoder. Rate quantization error is substantially reduced, thereby leading to more robust controller operation.

Abstract: A numerical control equipment comprises a control section for applying to a drive motor for driving a table on which an object under measurement is placed a movement instruction for moving said object to a theoretical position, a position register for receiving a detection signal outputted by a position sensor adapted to detect the position of the table, a memory unit for storing instruction data separately according to functions and uses, and a measuring head for measuring the difference between the stop position of the object and a reference position simultaneously with positioning of the object to the theoretical position, wherein said control unit operates a measurement value provided by the measuring head and a register value of the position register and rewrites the contents of addresses provided separately according to functions and uses in the memory unit with an operated value as a measurement result.

Abstract: A servo loop processor (2) is a dedicated controller for use with a main central processing unit (4) (CPU), through an appropriate interface (8,10) whereby closed loop control of a servo system (22) is achieved. Servo loop parameters as well as servo motor speed and/or position are downloaded from the main CPU (4) to the servo loop processor (2) through a configuration including a microcomputer (12) so that the main CPU (4) is free to perform other tasks.

Abstract: The invention relates to optoelectronic instrumentation engineering and, in particular, to cutting process control systems for CNC machine tools. A control system includes an optical transducer (2) mounted on a carriage (1) of a machine tool in the zone of movement of a cutting tool (8) and made up of a laser (10), and, mounted in the path of a beam (10') of said laser (10), a narrow-field slit diaphragm (12), a reference half plane (13) arranged in the plane of an axis (15) of rotation of a workpiece (9), a Fourier lens (19), and an electronic interface unit (3). The reference half plane (13) is located on the side opposite an apex (8') of a cutting wedge of the tool (8) in relation to the workpiece (9) so as to define an optically transparent slit (16) with the profile of a surface (17) of the workpiece (9).

Abstract: An interface system for a servo controller has a speed controller (7), a current controller (9), etc., which have heretofore been disposed on the side of a servomotor, disposed in a control circuit (15) on the side of an NC apparatus. The present position and speed data from the servomotor are fed back and are stored in a common RAM, and control signals for a driver circuit, such as an inverter (12), are supplied from the NC apparatus side to the servomotor side. A system bus on the NC apparatus side is directly connected to a local bus on the servomotor side.

Abstract: A method for controlling a working robot which is adapted to grip a workpiece for transporting it to a position where the workpiece is positioned against a working tool to be worked by the tool. The robot is positioned at a work starting position and at a work end position and in each of the positions the tool length vector is calculated. Based on the tool length vector values in the starting and end positions, intermediate tool length vector values are calculated for respective incremental points on a path along which the work is to be done by the tool for carrying out incremental compensations.

Abstract: A machine tool having a work spindle with an electrically actuated clamping unit including a three-phase motor with a stationary stator. The motor is supplied with electricity from a control unit operating with frequency conversion, and the control unit is alternatingly also used for triggering a spindle drive motor. A sensor detects clamping force applied to a workpiece, and produces a signal used to reduce motor speed of the three-phase motor until a predetermined clamping force is achieved.

Abstract: A metering method for an injection molding machine, which drives a screw with a servo motor in the axial direction to perform injection including the step of applying a back pressure during metering. In order to perform high-precision metering, the servo motor is driven even after the screw position has reached a metering point, so that the screw is held at the position of the metering point.

Abstract: A method and apparatus provides a three dimensional measurement of a point on an object. A surface with a system for detecting the position of sensors is placed adjacent to the surface and an assembly disposed adjacent to the surface yet freely movable within a plane is parallel to the surface. The assembly includes two sensors whose orthogonal projections into the surfce are detected by the two dimensional detecting system. The assembly further includes a probe, slidable only in a direction perpendicular to the surface and a system for detecting the perpendicular distance of the probe from the surface. In this manner, the orthogonal projection of the probe into the plane is permanently fixed in relation to the two sensors. In practicing the method of the invention, the object to be measured is placed adjacent to the surface and the assembly is moved to a position where the contact on the probe can be moved orthogonally until it contacts the spot on the object whose position is to be measured.

Abstract: An error-free pointing and tracking system is disclosed which separates the functions of pointing and tracking. Beginning with an initialized trajectory for an object, a sensor is positioned and deviations of the object position with respect to the sensor are noted. To the extent these deviations are trended, the gain of a trajectory correction algorithm is adjusted. Based on the adaptive gain trajectory correction algorithm, a new position estimate is determined. The new position estimate is corrected for servo lag error by referring to a predefined correlation between at least the acceleration term of the trajectory and prerecorded servo lag error. The position estimate, corrected for servo lag is used to then point the sensor.

Abstract: Device for setting the working point of a tool with respect to a reference point in an NC machine tool with a tool slide system and a path measuring system for the tool slide motion which is connected to a machine control system, and with a control sensor for transmitting a correction signal to the machine control system. The control sensor can be brought to the reference point, up to and over which the tool point can be moved by program control, starting from a starting point of the tool slide. The starting point of the tool slide and the reference point are spaced at a specified distance from one another and distances of the tool point from the starting point of the tool slide can be balanced by the machine control system against reference distances which can be evaluated by the machine control system on the basis of the correction signal and also on the basis of path measurement signals of the path measuring system.

Abstract: A honing machine in which a micro-processor controls reciprocation with respect to a work-piece of a spindle which carries honing stones, the micro-processor being associated with a memory unit which holds an acceleration profile in terms of position/time and being programmed to control reciprocation in accordance with the required acceleration characteristics. Variable stroke parameters and required mid-stroke speed are input from a console and the system ensures symmetrical honing under controlled acceleration regardless of any conflict between selected stroke length and mid-stroke speed.

Abstract: A rotary shaft position control apparatus in which the rotary shaft is stopped in one revolution. After detection that a flux emitter on the shaft has passed a position detector, the shaft speed is set to a first speed. The first speed is continued until a product of the first speed and the elapsed time at the first speed after passing the position detector equals a predetermined constant. Then, the speed is reduced to a second speed. Finally, the shaft is stopped when the flux emitter again passes the detector.

Abstract: An apparatus for measuring the shape and size of a rotary tool is provided which includes a tool rotation unit for rotating the tool around the tool axis, a tool moving mechanism for moving the tool in the axial direction, a measuring head having a line sensor, and a calculation control unit. The measuring head can be moved at a rate of a predetermined angle around a lateral shaft, located in a direction perpendicular to the axis of the tool, with one end of a measuring area of the line sensor as a center. Upon measuring the tool in terms of its shape and size, the aforementioned end of the line sensor is located in a position a given distance inside the aforementioned end of the tool, the line sensor is moved for every predetermined angle around a lateral shaft, with one end of the measuring area as a center, and measured values are fed to a computer through the line sensor, while the tool is rotated around its axis for every predetermined angle.

Abstract: An automatic changing apparatus includes a holder portion for storing a number of optical disks and a carriage for transferring a desired disk in the holder portion to a disk drive device. The carriage is moved by a drive mechanism and positioned in a desired position by a positioning device. The positioning device includes an absolute encoder which operates in association with the movement of the carriage to detect the position of the carriage. The drive mechanism is driven by a driver circuit in accordance with the difference between the position detected by the encoder and a desired position supplied from an input unit.

Abstract: A stock feed apparatus for feeding strips of stock to or from a stock processing machine to maintain a loop in the stock. The feed means is arranged to feed stock to or from the loop at speed correlative with the amplitude of a control voltage applied to the motor control. The stock loop sensor produces a first digital signal when the loop exceeds a first limit and a second digital signal when the loop exceeds a second limit. A loop control circuit is operative in response to the first digital signal to apply a control voltage of a first preselected amplitude to the motor control to drive the feed apparatus at a first speed until the loop moves away from the first limit and responsive to the second digital signal to apply a control voltage of a second preselected amplitude to drive the feed apparatus at a second speed until the loop moves away from the second limit.

Abstract: In a numerical control system for a machine tool using a general-purpose motor (11) in place of at least one of servo motors, a current position of a spindle (10) driven by the general-purpose motor (11) is detected (14, 9) and is compared with a position designated by a numerical control program. When the current position approaches the position designated by the numerical control program, brake signals (MBR, BR) are generated to brake the general-purpose motor (11) or the like, and a rotation signal (MCW, MCCW) of the general-purpose motor (11) is disabled, thereby stopping the general-purpose motor (11) so as to cause the spindle (10) to stop at the position designated by the numerical control program.

Abstract: The cam lift data is analyzed (110) through the use of a fast fourier transform (FFT) (116) to thereby obtain FFT coefficients (118) which define the amplitude and frequency content of the cam lift data. Through a combination of the kinematic model and an inverse FFT procedure, an axis control function including a position control function (Eq. 1 and Eq. 14) is determined (128) for each axis. Dynamic compensation (130) of each axis is provided for system lags and inertia loads by altering the axis control function as a proportion of the axis velocity and acceleration (130), respectively. For each controlled axis an independent vector and a corresponding dependent vector containing axis control data is generated (132). During the actual control of first and second drive motors (72, 70) of the grinding machine, position and velocity feedback signals are generated for each axis by feedback devices (82, 78).

Abstract: In a numerical control device for machine tools, a tool path is determined for a workpiece according to the machining data, and is divided into machining units, and the amount of machining for each machining unit is calculated to set a tool feeding speed data thereby to control the tool feeding speed of the machine tool.

Abstract: The present invention relates to a method of restoring a rotary axis to a reference point. A workpiece coordinate system serving as a programming reference with respect to a machine coordinate system is decided, numerical control (NC) program data are created including at least NC data specifying an angle r between an origin (WR) of the workpiece coordinate system and a reference point (MR) in the machine coordinate system, and rotational direction positioning data based on the workpiece coordinate system, and a rotary axis is positionally controlled based on the NC program data. The method includes updating present positions Pm, Pw of a fixed point Q on a rotary axis (11) in the machine coordinate system and workpiece coordinate system in dependence upon rotation of the rotary axis, obtaining an angle a that satisfies the equationsPm=360.multidot.n+a, Pw=360.multidot.n+a-rin response to a reference point restoration command, then rotating the rotary axis by .vertline.a.vertline..sup.

Abstract: In reference point return control, a grid point position at which a one-revolution signal (RTS) is first generated by a rotary encoder (24) following restoration of a deceleration limit switch (29) is adopted as a reference point. When a zero point return mode (ZRN="1") for returning a movable element to the reference point is in effect, a numerical controller (21) regards the position at which the one-revolution signal (RTS) is generated by the rotary encoder (24) as being zero. A commanded position REF.sub.n, until the next one-revolution signal is generated, is monitored at every predetermined time, such monitoring of the commanded position being repeated until the movable element arrives in the vicinity of the reference point. When the movable element approaches the reference point and the deceleration limit switch (29) is restored, the commanded position REF.sub.n at an initial time every .sub..DELTA. T is obtained, a distance (N-REF.sub.

Abstract: A print head motor control system for a printer having a bidirectionally movable print head employs a microcomputer to automatically calculate print head motor parameters which are utilized to generate a motor drive voltage value for any desired print head speed. Upon powering-up of the printer, the print head is driven until contact with the left sideframe is made. A full pass from left to right is then made checking for obstructions. The print head motor is driven at a first default drive voltage value, which is assumed to drive the print head at a first preselected velocity while the first actual print head velocity is measured. The printhead motor is then driven at a second default drive voltage value, which is assumed to drive the print head at a second preselected velocity while the second actual print head velocity is measured. The first default value, first actual print head velocity, second default value and second actual print head velocity are then used to derive a voltage vs.

Abstract: A minimum time path generation routine for a motion control system, where the routine is uniquely adapted for use in a digital mechanization.

Abstract: A feedforward path following routine for a motion control system, where the feedforward parameters are adaptively adjusted in real time during system operation for substantially error-free tracking of a third-order command path.

Abstract: A microprocessor based motor controller which provides open loop speed control at low conduction angles, closed loop speed control at high conduction angles, and a smooth transition between open loop and closed loop zones. In open loop, the motor speed is selected and is permitted to vary with applied load. In closed loop, the motor speed is held constant, substantially irrespective of load. In the transition zone, the motor is operated in a hybrid open loop, closed loop fashion.Anti-kickback protection is also provided based on a percentage change in the motor's rotational period.