Abstract: A system for the actuation of a setting element with a digital actuation device, particularly for a motor vehicle, wherein the digital actuation device is connected with a monitoring circuit which, upon failure of the digital actuation device, switches a by-pass of the digital actuation device. Preferably the digital actuation device comprises a microcomputer, from an output of which uniform signals are supplied during the course of the program, which signals are evaluated by the monitoring circuit.

Abstract: An electrical motor system is provided in which driver means position the motor, control the speed of the motor and control the current delivered to the windings of the motor. The operating parameters of the system are sensed on a moment by moment basis and data concerning these operating parameters is provided to a memory. A user has the ability to provide a plurality of user-stipulated operating parameters during use of the motor system. The user-stipulated operating parameters are sensed on a moment by moment basis and data concerning the user-stipulated operating parameters is provided to the memory. The memory contains limiting parameters, sensed operating parameters and user-stipulated operating parameters and a set of adaptive programs for determining the relationship between these parameters. The various parameters are fed to a computer which operates with them, via the adaptive programs, to create, on a moment by moment basis, a new set of operational limiting parameters.

Abstract: Disclosed is a control method in which control errors, attributable to a change of the state of a transmission mechanism, disposed between a servomotor and a load driven thereby, are reduced in controlling a driving force to be applied to the load.A detected value (PH) of the driving force applied actually to the load is compared with a set value (PL') of the force to be applied to the load. The driving current of the servomotor is controlled in accordance with the result of such comparison. Thereupon, a change of the correlation between the servomotor output and the driving force applied actually to the load, which is attributable to the change of the state of the transmission mechanism, is compensated automatically. Thus, the driving force applied actually to the load is adjusted accurately to the set value.

Abstract: In a numerical control equipment in which an image signal from an image unit and a display signal from a central processing unit (CPU) of the numerical control equipment are displayed on a single display unit selectively by a switching means provided in the apparatus, the display unit is driven in response to a synchronizing signal from the CPU and the equipment is equipped with a synchronized image signal feeding means for supplying the image signal to an input interface of the equipment in response to the synchronizing signal. With this construction, the input interface can be used commonly for various image units regardless of the type and characteristics thereof.

Abstract: A digital robot control is provided with cascaded position/velocity and torque control loops with microprocessor servo controllers in each. The servo controller includes two microprocessors that operate as a servo engine in providing motion control for six robot axes. One microprocessor is structured to perform data processing and coordination tasks. The other one performs calculation tasks and operates as a slave processor to the first.

Abstract: A tool move control method is disclosed. It comprises the steps of setting an interference area for an object which should not be interfered with a tool when a tool rapid move is instructed by a start point and a terminal point for the tool movement, setting an entry prohibit quadrant for prohibiting the tool entry and two or more of quadrants for permitting a move of the tool in the interference area, and controlling a move mode of the tool according to quadrants belonging to the start point and the terminal point in such a manner as to avoid the entry prohibit quadrant. A tool move control apparatus is also disclosed.

Abstract: Apparatus and methods are disclosed for use in monitoring the operation of an automated machine tool which has at least one linear slide axis. Motion along the various machine axes is detected and used to provide an output signal for synchronizing the comparison of real time monitored parameters with previously stored data which varies depending upon the operational stage of the part cycle in which the machine tool is operating. In one embodiment, a plurality of sections are stored in a memory. Each section contains limit values associated with normal characteristics of parameters such as power, vibration, acoustical emission and the like which occur during a given operational stage. A preselected detected change in motion along any of the slide axes initiates the generation of a new section of limit values to be used during the comparison. Provision is also made for inhibiting the comparison when the motion information indicates that the machine is not presently removing metal from the workpiece.

Abstract: A numerical controller for a grinding machine composed of a central processing unit (CPU), which is programmed to read out a numerical control program block by block from a memory device and to control a pulse generation circuit to generate pulses of such number and frequency as determined by the read-out data block, for supply to feed servomechanisms of the grinding machine. The CPU is also programmed to execute a trouble identification routine and a trouble processing routine at predetermined time intervals. The trouble identification routine enables the CPU to identify the kinds of troubles occurring in the grinding machine and to assort the troubles into a number of trouble modes.

Abstract: The present invention is intended to decrease the number of signal lines between a machine tool (1) and a numerical controller (3) and enable the current position of a movable machine part to be correctly recognized on the size of the numerical controller (3) at all times.Position sensing means (12) produces a detection signal each time the movable machine part moves a predetermined amount, and serial data generating means (16, 17, 18, 19) generates serial data representing the current position or the like of the movable machine part. Switching means (13) provides either the detection signal or the serial data on the same signal line connecting the machine tool (1) and the numerical controller (3). Follow-up means (21, 22) reproduces the detection signal provided from the position sensing means (12) during the transfer of the serial data.

Abstract: A system for the detection of broken and worn machine tools which may be employed to protect machine tools using one or more machine tool bits and an automatic sequence of machining instructions comprising one or more machining steps. Piezoelectric load cells translate the force applied between the machine tool bit and the workpiece into electrical signals, one of which is selected, sampled, and processed into a series of force values by an analog module, one average force value for every revolution of a machine tool spindle. For the first pass on a first workpiece by a particular machining operation, force value maxima are learned for each machining step, and broken and worn tool force limits are calculated from these force maxima for each machining step. During this learn pass, each recorded force value is compared against predetermined learn ceiling in order to protect the machine tool.

Abstract: An apparatus for sensing the location of a structural member on which a working operation is to be performed. The apparatus includes a probe that is connected to a rack and is mounted for movement between an inoperative position and an operative position, where the probe will be in engagement with the structural member. The rack is carried by a piston which is slideable within a cylinder and by introducing fluid pressure into one end of the cylinder, the rack will be extended to thereby move the probe from the inoperative to the operative position. Engaged with the rack is a pinion and linear movement of the rack will rotate the pinion and rotation of the pinion acts through a resolver to generate a signal indicating the precise position of the structural member.

Abstract: A method of determining an operating status of an adjusting drive of a printing machine having an electric motor drivable with varying direction of rotation, and a gear transmission arrangement includes determining a value of at least one of a torque produced by the electric motor and a variable dependent upon the torque, comparing the value with a corresponding value existing during an adjustment of the adjusting drive in a constant direction, and applying the value for a torque deviating by a given threshold value from the torque occurring during the adjustment of the adjusting drive in the constant direction as a criterion for an operating status deviating from the adjustment on the constant direction.

Abstract: This adapter has a housing containing an automatic electrical switching circuit, a plug for connecting the circuit to an external A.C. power source, and sockets for mounting primary and standby lamps on the housing in circuit with the switching circuit. The circuit includes a conventional rectifier bridge and a transistor which is normally biased off so that the standby lamp is off, when the primary lamp lights. When the primary lamp goes off (burns out), the transistor conducts and the standby lamp is automatically turned on. When the primary lamp again operates the transistor is again biased off and the standby lamp is automatically turned off. A signal lamp in the switch circuit lights when the standby lamp is on. Motors or other power consuming devices may be substituted for the lamps.

Abstract: The robot assembly of an industrial robot comprises a stationary robot component (11) and a plurality of movable robot components (12, 13, 14). At least parts of the stationary robot component and the movable robot components have airtight chambers (15, 16, 17) communicating with each other and intended to be kept at a pressure higher than a predetermined level which is higher than an external atmospheric pressure. Robot driving motors (18 to 23) for driving the movable robot components are arranged within the airtight chambers. A driving motor controller (27) for driving and controlling the robot driving motors is connected to the robot driving motors by means of electric cables arranged within the airtight chambers. Pressure switches (25) supply signals to the driving motor controller to stop the robot driving motors, respectively, upon detection of the pressure in the airtight chambers when the pressure in the airtight chambers drops below the predetermined level.

Abstract: To detect any abnormal loss of a feedback signal in an electric power system wherein a plurality of feedback signals are respectively derived from various system quantities, such as voltage and current, and are used as inputs to a controller that regulates the output of a controllable source of power, the controller is arranged to estimate the desired value of the system quantity from which a first feedback signal is derived, to compare the estimated desired value with the actual value of the same quantity (as indicated by the first feedback signal), and to signal a malfunction if this comparison reveals that the first feedback signal is faulty.

Abstract: A numerical control method for numerically controlling a machine tool such as a multi-spindle lathe having two or more tools (TL.sub.1, TL.sub.2, TL.sub.3). The numerical control method has steps of creating numerical control data specifying a relation between time and a position along each axis of movement (X.sub.1, X.sub.2, X.sub.3, Z), numerically controlling the position along each of the axes of movement (X.sub.1, X.sub.2, X.sub.3, Z) on the basis of the numerical control data, monitoring whether elapsed time has reached a time specified by numerical control data for each and every axis of movement (X.sub.1, X.sub.2, X.sub.3, Z), and when elapsed time has become equal to a time specified by numerical control data for a predetermined axis of movement, controlling the position along the axis of movement in accordance with succeeding numerical control data for the axis of movement.

Abstract: In a control system for a robot having a servo motor driving an operation axis, position error detecting means, detects an error of the actual position with reference to a desired instantaneous position, and a drive circuit receives the position error for supplying a current to the servo motor to reduce the position error. The control system is characterized by means for limiting the current supplied from the drive circuit to the servo motor thereby to limit the torque of the servo motor when the servo motor is driving the operation axis in a first mode in which movement of the operation axis is subject to undesired obstruction.

Abstract: In order to execute a series of moving sequences by synchronous and exclusive control of unit operations taught or programed in advance, there are provided a first storing of the relationship of the sequence of execution of each unit operation to other unit operations to be controlled synchronously or exclusively; a second storing of information relating to the operational status of each unit operation; and a third storing of operating instructions for executing each unit operation. When machine tools have stopped due to the occurrence of an abnormality while a series of unit operations are being executed by the operating instructions stored in the third storing means, a unit operation for restarting on the basis of the relationship of the executing sequence stored during the first storing is appointed, and information concerning the operational status stored during the second storing is corrected.

Abstract: An apparatus for providing asymmetrical torque-switching for an aircraft autopilot. The invention provides an increased amount of available pitch servo torque at high altitude. The direction of pitch of the aircraft is sensed. An increased amount of torque is provided for the pitch-up direction thereby providing more positive control of the aircraft.

Abstract: A tool display system of an automatic tool changing apparatus (31) in a machine tool (30) sequentially controlled by a programmable controller (20) on the basis of a control signal from a numerical control unit (1). The tool display system is equipped with a memory (21) for storing the positions of a plurality of pots (31b) provided on a tool magazine (31a) accommodating tools, and a display unit (14) for displaying the tool information stored in the memory (21). The display unit (14) displays a graphic pattern representing the positions of the plurality of pots on the tool magazine (31a) as well as the present positions of tools accommodated in the tool magazine, the latter appearing inside the graphic pattern.

Abstract: An industrial robot system comprising a robot disposed in an environment having peripheral equipment and operable under program control of a control unit to shift between a normal job mode of operation and an earthquake mode of operation, an earthquake detector which produces an output in accordance with an earth vibration exceeding a predetermined value, and earthquake mode controller disposed between the earthquake detector and the control unit for generating a control output in response to the output of the earthquake detector to interrupt the normal job mode of operation of the robot and shift the robot to the earthquake mode of operation, whereby on the basis of the output of the earthquake detector, the normal job mode of operation of the robot is suspended through the earthquake mode controller and an actuator of the robot is moved in a direction away from peripheral equipment of the robot.

Abstract: The condition of the cutting tool is monitored during a turning operation and the machine is adjusted to compensate for tool condition. The device is also used as an in-process part inspection system. A probe on the cutting tool-tool holder assembly measures the distance to the freshly cut surface and the probe signal is monitored; when this distance changes indicating tool nose wear, the numerical control is alerted to adjust the tool during the chip-forming operation to compensate for wear. A broken or worn-out tool signal shuts down the machine. After a cutting pass the part is inspected by retracting the cutting tool and running the part program. There is an error in the part when the probe signal and thus the measured distance is not constant.

Abstract: A feedpath deviation preventive NC path-controlled machining system in which a plotting unit is used, in a preliminary operation in advance of a machining operation, to produce on a record medium a continuous plot equivalent to a programmed machining feed path to be followed by relative displacement between the tool member and the workpiece during the machining operation. In the latter, a sensing head is disposed in sensing relationship with the plotted record medium for relative displacement to the latter jointly with the relative displacement between the tool member and the workpiece. The sensing head continues to trace the continuous plot as long as the actual machining relative displacement proceeds along the programmed machining path to produce an OK signal.

Abstract: The user of a remotely controlled, powered manipulator is provided with audible feedback signals which provide useful information relating to the force and speed of the motor. An audio tone is generated and is frequency modulated by a signal which corresponds to motor speed. The tone is amplitude modulated by a signal corresponding to motor force thus providing the user with an intuitively interpretable feedback signal having a speed-proportional pitch and force-proportional volume. In the case of an electric motor, voltage and current can be monitored to provide speed and force signals respectively. Additional modulation means are disclosed for introducing a force-proportional warble component to said tone.

Abstract: The directions of travel of an inner and an outer loop actuator are monitored for movement in opposite directions within selected ranges and the outer loop actuator is disabled under selected conditions. These conditions may include movement of both the inner and outer loop actuators in opposite directions, any one of which has been detected moving at a rate greater than a selected rate or to a position outside a selected range. The invention is particularly suited for an aircraft trim actuator shutdown monitor system.

Abstract: A speed monitoring circuit is disclosed for an automatic positioning system. This speed monitoring circuit composes a measurement of the actually present speed determined from measurement signals generated by an incremental position measuring device with the desired speed commanded by the positioning system. The difference between the actual and commanded speed is detected and, in the event of an excessive deviation, a warning or an automatic termination of operation of the positioning system is provided. In the disclosed system, the desired speed is determined by a controller in which a digital computer calculates the difference between the instantaneous position of one relatively movable machine component and the desired position of the movable component as established by programmed data.

Abstract: The capability of compensating automatically for a failure in an actuator and the associated drive circuit is enhanced by providing a dual channel actuator, each channel having a drive coil and a position sensor tracking the position of the actuator output shaft. A separate circuit is provided for each actuator channel to detect drive loop failures and hydraulic failures. When the drive loop of one channel fails, it is disengaged, and the gain in the remaining drive loop is doubled to maintain authority. In an embodiment, the remaining drive loop cannot disengage when certain criteria, relating to the failure of associated actuators, are met. The invention is particularly useful for aerospace applications.

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: The present invention is to increase the reliability of a numerical controller by permitting the detection of an abnormality in a position sensing pulse which is output each time a moving part moves by a fixed amount.A position sensor (6) outputs a reference position sensing pulse each time a moving part reaches a predetermined position, and a direction discriminating circuit (7) outputs a position sensing pulse each time the moving part moves by a fixed amount. A reversible counter (8) counts the position sensing pulse from the direction discriminating circuit (7), and abnormality detecting circuits (9) and (10) detect an abnormality in the position sensing pulse on the basis of the count value of the reversible counter (8) and the generating timing of generation of the reference position sensing pulse.

Abstract: A multiplex control system including a plurality of controllers, the main controller being arranged by hardware, while the subsidiary controller being accomplished by software. Each of the controllers has a PID operator for calculating the proportional, differential and integral components of process data, and the difference of the integral components of both PID operators is processed through a first-order time lag operator and the result is used to correct the error of the output from the PID operator of the subsidiary controller. In the occurrence of abnormality, control of the control object is switched from the main controller to the subsidiary controller using the first-order time lag element attached to the switch unit thereby preventing the tracking of control data.

Abstract: A printer in which a platen is secured to a machine frame, a carriage is movably supported on the machine frame for movement along the platen, a motor is movably supported on the carriage for reciprocal movement in a direction at right angles to the direction of movement of the carriage towards and away from the platen, a pedal type wheel is fixedly secured to the carriage and has a plurality of types, mating coupling means is formed on each of the motor and type wheel, detection means is provided to generate a detection signal upon detection of a particular rotational angle of the motor during one complete rotation of the motor, a drive circuit is provided to drive the motor and a control circuit is provided to determine presence of a detection signal and arrests the rotation of the motor when no detection signal is generated within a predetermined time period required for the motor to rotate one complete rotation.

Abstract: In a feed control system, a feed controller controls a servomotor in such a manner as to reduce the difference between an objective position and a present position of a movable body. An interference detection circuit coupled to the feed controller detects the occurrence of an interference between the movable body and an obstruction when feed movement of the movable body is discontinued nevertheless the difference between the objection and present positions does not reach zero. A digital computer is coupled to an objective position counter provided in the feed controller to selectively set therein objective positions to which the movable body is to be positioned successively. The digital computer, when receiving a signal from the interference detection circuit, sets the objective position counter with data for moving the movable body a predetermined amount in a direction opposite to that wherein the movable body was moved before the occurrence of an interference.

Abstract: A tracer control method whereby a tracer machining inhibit area is set and tracer machining is performed while skipping the machining inhibit area, the method including presetting a tracer machining inhibit area (TMI) and a safe level (ZL.sub.s) after taking into account the shape of a model (MDL). The method also includes moving a tracer head along the surface of the model to perform tracer machining in an area (TM), inhibiting tracer machining when the tracer head reaches the machining inhibit area (TMI), and raising the tracer head to the safe level (ZL.sub.s). After reaching the safe level the method includes moving the tracer head along the safe level to a boundary of the machining inhibit area after the tracer head reaches the safe level, thereafter performing an approach operation, and resuming tracer machining in an area (TM') after the approach is completed.

Abstract: In each drive direction of a degree of freedom, or in each of the drive directions of several degrees of freedom, the industrial robot is provided with an absolute measured value transmitter or transducer and a relative measured value transmitter which give the instantaneous position of the drives. Should the signal put out by the absolute measured value transmitter not fall within a preselected range of a first window circuit, the robot will be switched off via the control because the robot is moving in a unpermitted working region. The reference position can be chosen with the aid of a second window circuit whose window lies within the range of the first window circuit.

Abstract: For adjustment to various formats in accordance with the products to be packaged and the packages used, structural parts, tools and devices of a packaging machine are equipped to be adjustable. In order to be able to effect adjustment as intended and quickly by means of displaceable parts equipped with set screws at the changeover locations, the packaging machine has a mobile drive unit, which can be coupled with the set screws of the various changeover locations. The drive unit is controlled by a control unit which is programmable in accordance with the format, and is used by the operator at a given changeover location as indicated by the control unit.

Abstract: A method of monitoring the performance of a cutting tool which moves relative to a workpiece through a cycle including the steps of dividing the cycle into a plurality of increments, sensing the function of force applied to the tool during each of the increments, determining and storing the highest function of force and lowest function of force applied to the workpiece during each of the increments, setting a maximum differential function of force limit, calculating the difference between the highest and lowest function of force sensed during each increment and comparing the calculated function of force differential with the set maximum function of force differential and establishing a signal when the calculated function of force differential exceeds the set maximum differential. In the preferred embodiment, the function of force is torque.

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: A microprocessor-controlled antenna positioning system for automatically steering a rotatable antenna in the direction of a source of radiated signals is disclosed. The present invention, which is particularly adapted for use in a television receiver or a subscription television receiver (STV) decoder, automatically seeks the best signal when a new channel or frequency is selected, remembers that preferred antenna position, and will return to it whenever that channel or frequency is subsequently selected. A large number of desired antenna headings may be stored in memory for subsequent use and the computer-selected antenna heading may be modified to avoid TV ghosts or to select a second station on the same channel. The system determines optimum antenna direction by sweeping the antenna through a full 360.degree. circle, keeping track of the width of receivable signal lobes.

Abstract: A servo motor feedback fault detector that combines the motor drive voltage, the current flowing through the motor and the rotational speed of the motor and compares this combined signal with a dynamic threshold generated by combining a percentage tolerance of the motor current with a percentage tolerance of the motor rotational rate.

Abstract: The invention relates to a mechanism wherein a relative rotary angle of a driving motor is detected by use of an encoder, and, if an error occurs in a servo control action when the driving motor is servo-controlled in accordance with a deviation value of the relative rotary angle from a desired rotary angle of the driving motor, then the servo control action is brought to an emergency stop. A potentiometer for detecting an absolute rotary angle of the driving motor is connected to a rotary shaft of the driving motor and said emergency stop is effected when a difference between said absolute rotary angle and said relative rotary angle exceeds a preset tolerance value, so that an error in the servo control action can be reliably prevented.

Abstract: Each of some automatic machines, such as an industrial robot of the type having a servo-amplifier (4) controlled by a central processing unit (1) through a servo-control (3), has a plurality of control modes for moving a movable part (50), for example, teaching and playback modes. In the specified control mode, for example, the teaching mode, the velocity or driving force of the movable part (50) is restrained directly via a man-machine interface (7) by controlling either or both of the servo-amplifier (4) and a power source (5) to regulate driving energy supplied by a servo-motor (8) to the movable part (50) so as to mitigate danger to a person who is near the movable part.

Abstract: A circuit which monitors air flow by comparing the speed of a fan to a predetermined frequency. A Hall effect device detects magnetic pulses representative of the fan speed and provides a corresponding electrical signal. This signal is compared with a predetermined threshold frequency by a retriggerable monostable multivibrator. A digital delay circuit isolates pace conditions and a relay circuit provides an indication of the fan speed status.

Abstract: An improved electronic controller for an automobile power seat system is disclosed. The electronic controller features a microcomputer which receives command signals from a first and second group of operator actuable switches, present position signals from a monitoring circuit, and stored position signals from a memory circuit for generating control signals for directing a motive power means to adjust the position of an automobile seat. The monitoring circuit includes transducer means for sensing the current draw from the d.c. power source, and differentiating means connected to the transducer means for generating a pulse concomitantly with each commutation of the motor from the motive power means. These pulse position signals are sent to the microcomputer and then counted by an internal timer for determining the present position of the automotive seat.

Abstract: A method of diagnosing a servomotor position control circuit which includes a pulse distributor for carrying out arithmetic operations for pulse distribution based on command data given by a control unit, a position detector for generating a positional pulse each time the servomotor rotates through a predetermined angular interval, an error storage unit for computing and storing the difference between the number of positional pulses generated by the position detector and the number of distributed pulses generated by the pulse distributor, and a D/A converter for converting the difference into an analog output, whereby the servomotor is controlled by the analog output from the D/A converter.

Abstract: A method for monitoring the alignment of the read-write head of a magnetic media data storage device comprising the steps of: establishing an elasped time window during which the read-write head should pass through a predetermined position if the head alignment has not drifted; checking to determine if the actual time at which the read-write head passes through said position actually falls within said window; and providing a pair of signals for indication of alignment or misalignment.

Abstract: A safety system and method for industrial robots includes a detection arrangement having a detection field covering the area of reach or operation of the robot. Detection data obtained through the detecting arrangement in each of predetermined operation positions of the robot is compared with the detection data indicative of the normal or correct detection field in the same operation position. The movement of the robot to the next operation position is prohibited when a difference of a level exceeding a predetermined level is obtained during the comparison.

Abstract: A method for preventing interference between relatively moveable components of a computer controlled industrial machine in which the position of the moveable machine elements are controlled by a computer program. For each movement, the computer first determines a predicted path for the movement and thereafter determines whether the path will intersect a safe zone, a safe zone being defined as a zone containing an element which is to be protected from contact with the moveable element. If a predicted path intersects a safe zone, the machine operation is halted. Provision is made for manual moves, i.e., movements not directed by the computer up to the nearest intersection point with a safe zone.

Abstract: A digital controller includes a central processor unit for generating a processed signal to be stored in an up-down counter. A manipulation signal generation circuit converts the contents of the up-down counter to a manipulation signal for an actuator. A feedback signal from a first coupling circuit connected to the up-down counter through a pulse width converter is applied to the central processor through an analog input circuit. The output signal of the up-down counter from the first coupling circuit and the output signal of the manipulation signal generation circuit are compared by a monitor circuit. An abnormality detection signal of the monitor circuit is generated as a result of the comparison and is applied to the central processor unit through a second coupling circuit.

Abstract: A disk drive control circuit designed to eliminate undesirable mechanical resonances that occassionally occur in the disk drive system as a result of a particular combination of seek commands. The control circuit uses an electrical model of the mechanical system in order to estimate or predict whether a particular seek command is likely to excite a mechanical resonance. The electrical model may be a filter network having frequency response characteristics similar to the mechanical system. The current used to drive a linear motor of the mechanical system is then applied to the filter network. The signal output from the filter network, which network effectively models the mechanical system, is thus representative of the mechanical response of the system upon performance of the seek operation. This signal output is monitored, and if it exceeds a predetermined threshold level, steps are taken to alter the system response so as to avoid exciting the mechanical resonance.

Abstract: A numerical control apparatus for a machine tool (4) comprises a transmitting circuit (43) for transmitting each block of machining information to an abnormal operation monitoring apparatus (6), which comprises a receiving circuit (61) for receiving each of said blocks of machining information and a decoding circuit (63) for decoding the content of said received blocks of machining information, thereby, as the machining proceeds by each one block, data indicating the content of said block and a signal indicating the termination of execution of the machining operation defined in said block are supplied from said numerical control apparatus (4) to said abnormal operation monitoring apparatus (6) and said content of each block of machining information is decoded in said abnormal operation monitoring apparatus (6).