Abstract: In a rotation detection apparatus, a magnetism pattern section provided with plural magnetic poles and a FG (frequency generating) pattern section provided with plural toothed wire circuits are located so as to face each other. When either one of the magnetism pattern section and the FG pattern section is rotated together with a rotating member, plural wave signals are electrically induced in the plural toothed wire circuits. A signal processing cicuit synthesizes the plural wave signals so as to output a multiplication signal and detects the rotation of the rotating member based on the multiplication signal.

Abstract: An apparatus and method for providing disturbance-free speed and position references to drive units in a web-fed printing press to minimize or eliminate detrimental effects on printing speed and quality caused by transient mechanical disturbances occurring at one or more of the drive units during printing.

Abstract: The invention relates to a method for controlling an electric motor, in particular of a brushless electric motor, whereby the absolute phase position of a rotor in relation to a stator of the electric motor (4) is determined, and to an apparatus for the method. A characteristic feature of the invention is that one or several movement(s) of the rotor are excited, the absolute phase position of the rotor in relation to the stator is measured, and the absolute phase position is deduced therefrom.

Abstract: An apparatus and method for estimating rotor position in and commutating a switched reluctance motor (SRM), using both a flux/current SRM angle estimator and a toothed wheel generating a magnetic pickup. Commutation is based on the flux/current SRM at startup and lower speeds. At higher speeds, when magnetic pickup sensed from the toothed wheel is sufficiently large in amplitude to create frequent reliable interrupts, commutation is based on signals from the toothed wheel magnetic pickup. Phase errors can be compensated by adjusting the angle input to the commutator as a function of estimated speed. Alternatively, the flux/current SRM angle estimator can be run in a background mode to tune the toothed wheel interrupt angle signal at different speeds.

Abstract: A driving circuit of a direct current brushless motor is provided. The circuit includes a sensing portion, arranged around a rotor, for generating sensing signals according to a position of the rotor, and a stator coil controller for supplying current to each stator coil using the sensing signals, wherein when the rotor is sensed, the sensing portion generates a first sensing signal having a predetermined high-state interval longer than a half rotating period, and a second sensing signal having the predetermined high state interval starting before the high-state of the first sensing signal is finished, and wherein the stator coil controller supplies current to the stator coil during the time when one of the first and second sensing signals is low. Accordingly, since it is not necessary to control phases of rotor sensing signals, the circuit is simplified and consumption power is reduced.

Abstract: A servo controller for servo-controlling an operative device, the servo controller is provided with an actuator having a motor for actuating the operative device; a sensor for detecting an operational state of the operative device; a comparator for receiving a detected operational state of the operative device from the sensor and comparing the detected operational state with a target operational state to produce a control signal; and a driver provided between the actuator and the comparator for driving the actuator in accordance with the control signal, the driver including a negative impedance circuit with respect to the actuator.

Abstract: A micropositioner has a coarse positioner and a fine positioner, with a separate closed loop control circuit for the fine positioner. A disk head being positioned over a disk is attached to the stage of the fine positioner. The fine positioner includes a parallelogram flexure having first and second opposite sides attached respectively to the coarse positioning stage and the fine positioning stage. A piezoelectric translator translates the second side of the flexure relative to the coarse positioning stage. In order to sense displacement of the fine positioning stage relative to the coarse positioning stage, a differential electric field sensor is employed. The sensor includes a pair of side plates both mounted fixedly relative to one of the stages and opposing each other to create an electrical field between them, and a probe plate mounted fixedly relative to the other of the two stages and between the two side plates.

Abstract: A rotation position detecting circuit for a sensor-less motor and a motor device include a motor (1) which is rotated and driven by adding a sensor signal having a high frequency to a sine wave drive signal and cosine wave drive signal through adders (5S) and (5C), respectively. Further, a sensor signal is extracted and demodulated from a signal flowing in the motor (1) by a band pass filer (9), and this is defined as a rotation position detection signal. In the sensor signal from the band pass filter (9), its current value is changed corresponding to a change of an impedance resulting from a rotation of a magnet of the motor. As a result, it is possible to detect the rotation position of a rotor magnet by detecting the change of the current value.

Abstract: A time-based control system (10) for controlling a process incorporating external devices using a predefined response profile (13). The response profile (13) is continuously compared to the actual response of the controlled device (11). A plurality of sensor modules (24) is used to monitor the actual magnitude and direction of change of selected quantities during the process. If the response it outside the user-defined maximum allowable error, appropriate measures are taken to either correct the error, halt the process, or proceed with the process in a time-based mode. The proper response and detection of errors of the controlled device (11) is independent of load, rate, temperature and other external stimuli. The time-based control system (10) can detect errors caused by higher level equipment such as the sensor modules (24). Thus, the time-based control system (10) can detect when any portion of the time-based control system (10) or the controlled device (11) malfunctions.

Abstract: An HGA loader for a flying height tester. The loader includes a clamp that holds a head gimbal assembly (HGA) of a hard disk drive. The clamp is mounted to a pivot assembly that is coupled to a ball screw by a transfer housing. The ball screw is rotated by a belt that is coupled to an electric motor by a pair of pulleys. Rotation of the ball screw moves the transfer housing and clamp between a first position and a second position. The loader has a pair of stops that impede the movement of the transfer housing so that the clamp cannot move beyond the first and second positions. The stops are adjustable so that the first and second positions can be varied. The motor pulley has a clutch that allows the motor to turn even when the clamp reaches the first and second positions. The clutch allows the motor to continue rotation and maintain a proper motor count even when the ball screw and driving belt have stopped moving.

Abstract: A wafer prober for testing uncut die of a semiconductor wafer has an alignment accuracy in the X-Y plane within the sub-micron range. The wafer, held by a chuck, is positioned in the X-Y plane by using a pair of linear servo motors each driven by a servo drive unit providing drive control, monitoring and diagnostic functions. Positional information is obtained from a pair of linear encoders, one along each drive axis. Positional information is also obtained from a pair of resolvers, one for the vertical axis and the other for rotational position about the vertical axis. Ways and runner blocks are used to provide substantial downforce capability and high speed translational movement. In addition, the present invention uses a general purpose computer providing for an on-board controller card interfacing with the servo drives via a fiber optic coupler.

Abstract: An automated guided vehicle includes a body, at least one driver wheel for propelling the body along a surface, at least one steered wheel for directing the body with respect to the surface and a body-based inertial navigation system. The inertial navigation system senses actual movement of the body in at least three degrees of freedom. Such sensing is accomplished notwithstanding the presence of side slippage of the vehicle. This can be embodied in an automated guided vehicle having a ground track sensor which continuously senses relative movement of the vehicle with respect to the surface being traversed in order to determine an actual velocity vector of the vehicle. The ground track sensor may physically contact the surface in order to sense the relative movement or may be a non-contact sensor. The disclosed navigation system is especially useful with tugger automated guided vehicles.

Abstract: Process and apparatus for preventing collisions between two machine components, of which at least a first machine component is displaceable by means of a drive along a straight track relative to the second machine component such that the two components can collide, wherein for the simple and reliable prevention of such collisions a sequence of pulses is generated during movement of at least one of the two components relative to the other component by means of signal generating devices associated with the two machine components, namely such that the distance and/or the length and/or the height of consecutive pulses follows a function of the distance of the two components from one another, measured in track direction, and wherein the drive is controlled as a function of this sequence of pulses.

Abstract: A method of and an apparatus for controlling the drive of a machine element of a spinning or twisting machine for exact positioning of the machine element at setpoint positions within a certain tolerance limit using motors which are not speed variable and are controlled by an on-off switch. The overshooting of the setpoint position can be detected and the measure of overshoot used as correction values for subsequent approaches to the setpoint position or to allow reverse approach to the setpoint with detection of overshoot beyond the tolerance and then a new approach with the iteration to a deviation less than the tolerance limit or a maximum number of cycles.

Abstract: An automatic focus adjustment device which accurately performs end point detection of the range of movement of a photographic lens to smoothly drive the photographic lens completely to a focus position. The automatic focus adjustment device includes a defocus amount detection device to detect a position deviation of the image position of a subject formed by the photographic lens from an image forming plane. An actuation amount necessary to drive the photographic lens by the detected defocus amount is calculated. An actual actuation amount decision device decides whether the actual actuation amount output to drive the lens is within a permissible range predetermined for the drive.

Abstract: A control system is provided for a door positioning assembly having a door mounted on a track. The door is movable between an open position and a closed position. The door has a leading edge adjacent a door opening, an edge arranged to define a second opening, and a pass door pivotably coupled to the second opening. The control system includes a proximity detector for providing a door position signal in response to the position of the door on the track system, and a user input for providing user input signals including open inputs, stop inputs including signals provided by a stop button of a user-operated switch, and close inputs in response to user commands. The system also includes a plurality of sensors for providing stop input signals in response to the position of an object located within a detection zone adjacent the door opening, in response to contact between an object and the leading edge of the door, and in response to the position of the pass door.

Abstract: In an encoder output method and a servo motor encoder according to the present invention, the number of signal lines is reduced by using common signal lines and common output terminals. In the encoder output method and the servo motor encoder, incremental signals (A, B, Z) and servo motor magnetic pole position detection signals (UE, VE, WE) are switchably output by a common driver (2) through a pair of timers and a multiplexer (30), or a pair of timers and two line drivers (60, 70) are selectively active or inactive, and common signal lines are used, thereby reducing the number of signal lines.

Abstract: The invention provides a servo motor encoder in which signals are output via signal lines and output terminals which are used in common. Incremental signals A, B, and Z and servo motor magnetic pole position detection signals UE, VE, and WE are switched by a multiplexer so as to output these signals via a common line driver. Alternatively, two line drivers are selectively activated and inactivated so that incremental signals and servo motor magnetic pole position detection signals are output via common signal lines. In any modes, signals can be carried via a less number of signal lines.

Abstract: A method and system for controlling an electromechanical actuator assembly and measurement of actuator position via two drive wires to the actuator assembly. The system includes sensing the changing inductance of the actuator through the electrical drive line and associating the sensed inductance with a corresponding position of the actuating member.

Abstract: An absolute encoder which is operative to provide a plurality of signals indicating a current position, that signal including a least significant bit whose edge is detected and used as a basis for adjusting the current value under a variety of circumstances, typically based on the speed of the encoder. If the encoder is operating at high speed, a predetermined value may be assigned to the current position, while if operating at low speed, the value may be edge settable at least once at speeds below a limit value.

Abstract: A servo-control system for actuating an aircraft flight control member, the system including at least one hydraulic actuator together with actuation means for actuating said actuator, said hydraulic actuator being duplicated, said actuation means including first and second actuation assemblies each comprising two hydraulic circuits each controlled by a respective mechanically-controlled distributor valve, the two distributor valves of the same actuation assembly being actuated by common mechanical elements caused to move by motor means, the actuation means including control means controlling said motor means as a function of the position of the flight control member and of piloting orders received by the control means, detection means for detecting failures, and a selector valve which controls switching of the actuation assemblies between an active state and a reserve state.

Abstract: An automatic door opening and closing system opens a door by driving means when a person approaches the door. A monitoring area is set in the vicinity of the door, and moving speed and direction computing means computes the speed and direction of movement of the person on the basis of changes in position of the person in the monitoring area. When it is judged from the computed direction of movement that the person is moving toward the door, door enabling area selecting means selects one of plural door enabling areas suitable for the speed of movement of the object. Open-door command means provides an open-door signal, which causes the door to be opened at a fixed speed, to the driving means so that the door is fully opened upon the predicted arrival of the person at the door.

Abstract: A position control system which includes a plurality of actuators for moving an object, a plurality of sensors for detecting the state of the object, a first circuit for extracting a state signal, in each of different kinetic modes related to the object, from outputs of the sensors, a compensating circuit for compensating for the state signals in the respective kinetic modes, a second circuit for distributing an output of the compensating circuit and for providing drive signals for the actuators in accordance therewith, and a driver for driving the actuators in response to the drive signals.

Abstract: A system for controlling the operation of a tele-operated machine uses a sensor which senses the angular orientation of the joint, converts the angular orientation to a required length of the linear actuator (piston and cylinder) to obtain the then current length. A controller inputs the desired position of the joint and the system defines the length of (or flow to) the linear actuator necessary for the joint to be in the desired position based on a comparison of the desired and actual lengths of the actuator and sets the length of (or flow to) the actuator based on the required length (or flow) necessary to move the joint into the desired position i.e. to extend the length of the actuator to that required for the desired movement of the joint.

Abstract: An actuator having electronically controllable tactile responsiveness which is flexibly programmable to facilitate provision in a single actuator of torque-position characteristics, such as a selectable number of detents per actuation through its full operative path. A rotary actuator facilitates provision in a single actuator, of torque versus angular position characteristics, such as a selectable number of detents per revolution. The actuator is in communication with a servo motor having a position encoder which outputs position information to a controller that has access to torque-position relation information. The controller outputs a digital torque signal, in accordance with the torque-position relation information, which is converted to an analog current signal applied to the servo motor to generate torque in the servo motor. The torque, presenting a tactile response to a human interacting with the actuator, is sensed as a detent or a plurality of detents.

Abstract: Displacement measuring apparatus for measuring the displacement and movement of an object includes a sensor having an operative surface and circuitry for producing an electrical output signal whose value is dependent upon the area of the operative surface covered by an electrical/magnetic field producing member. The apparatus also includes an elongate, flexible band capable of producing an electric/magnetic field, where the band is attached at one end to the sensor to roll over and cover or unroll from over and uncover the operative surface as the object whose displacement is to be measured is moved. The value of the electrical output signal produced by the circuitry is thus dependent upon the area of the operative surface covered by the band and thus by the position and movement of the object.

Abstract: A method for providing motion information for a motor controller is accomplished by defining a determined set of motion parameters for describing a desired motion in terms of encoder position data. The parameters are stored for use in calculating the desired motion profile of the motor during the various motion segments of the desired profile as the motor is being driven. The method saves on required memory storage for all the various motor profiles typically used in devices such as inserters since only the parameters used in calculating must be stored. A flag field is also provided to enable the microprocessor to determine which of the segments is being generated.

Abstract: A hybrid servomechanism includes a speed control, a rotor position control and a brushless motor. When enabled, the position control commands a stationary stator mmf vector, allowing the motor's rotor to rotate until load torque and motor torque are balanced. This position control eliminates limit cycle operation and allows the motor to compensate for backdriving caused by external loads.

Abstract: A method of and an apparatus for controlling the drive of a machine element of a spinning or twisting machine for exact positioning of the machine element at setpoint positions within a certain tolerance limit using motors which are not speed variable and are controlled by an on-off switch. The overshooting of the setpoint position can be detected and the measure of overshoot used as correction values for subsequent approaches to the setpoint position or to allow reverse approach to the setpoint with detection of overshoot beyond the tolerance and then a new approach with the iteration to a deviation less than the tolerance limit or a maximum number of cycles.

Abstract: A method and apparatus for defining a reference position of a tool with respect to at least one direction of movement is provided. The reference position is defined by comparing a position to which the tool has been commanded with the actual position of the tool with respect to the direction of movement. Lag data indicative of the difference is compared to a predetermined lag value, and advancement of the command position is terminated in response to lag data exceeding the predetermined data. The reference position is defined with respect to such lag data.

Abstract: An integrated compliance electrohydraulic servovalve system connected to a load such as a simulated living being to provide more realistic movement thereto. The system includes a pressure transducer for sensing the pressure appearing at the output of the electrohydraulic servovalve and which is applied to an actuator connected to the load. The pressure as sensed is developed into a corresponding electrical signal which is used as a feed back signal to the drive motor of the electrohydraulic servovalve. The actuator position signal is also provided and is summed with the position command input signal to provide the command signal which is also summed with the pressure signal prior to application to the drive motor. The utilization of the pressure feed back signal provides compliance to the over all system resulting in a realistic movement of the simulated living being.

Abstract: A positioning stage wherein encoder pair means on a table which is movable on a frame by a drive and transmission system generate a signal independent of lost motion in that system so that a microprocessor can fix the position of the table in a predetermined position with respect to the frame irrespective of that lost motion.

Abstract: Displacement measuring apparatus for measuring the displacement and movement of an object includes a sensor having an operative surface and circuitry for producing an electrical output signal whose value is dependent upon the area of the operative surface covered by an electrical/magnetic field producing member. The apparatus also includes an elongate, flexible band capable of producing an electric/magnetic field, where the band is attached at one end to the sensor to roll over and cover or unroll from over and uncover the operative surface as the object whose displacement is to be measured is moved. The value of the electrical output signal produced by the circuitry is thus dependent upon the area of the operative surface covered by the band and thus by the position and movement of the object.

Abstract: A method for the adjustment of a disk cam, whereby an electric motor turns the disk cam out of a prescribed initial position by a prescribed rotational angle, comprising the steps of providing a disk cam having two markings in a prescribed angle from one another defining a target sector; sensing said two markings during the rotational motion of the disk cam by a sensor stationarily arranged outside the disk cam; in the initial position of the disk cam arranging the sensor having an angular spacing from a target radius of the target sector in rotational direction that is aligned to the rotational angle; identifying the running time of the passage of the markings at the sensor; and arresting the motor in response to the sensing of the second marking and supplying the motor with electrical energy for turning it in the opposite rotational sense, the amount of this energy dependent on the respectively identified running time, being taken from an energy/running time characteristic for the return of the disk cam to

Abstract: Spaced cutting tools, each having a plurality of linear axes and a rotational axis, are supported with a conveyor carrying successive parts past the tools. The tools include positioning motors and are positioned by a computer driven system including a controller and a tool program for positioning the tools to sequentially cut each part. Separate computer boards each include a memory unit and a CPU for coupling to individual positioning motors for each tool. The controller downloads the program for particular axes to the board for the tools. A positioning sensor is coupled to each tool axes and connected to the computer input for monitoring each tool position. All tools are simultaneously positioned using an initial fast constant speed feed followed by a varying slow speed, with a closed loop control, within a fixed time period.

Abstract: An actuator having electronically controllable tactile responsiveness which is flexibly programmable to facilitate provision in a single actuator of torque-position characteristics, such as a selectable number of detents per actuation through its full operative path. A rotary actuator facilitates provision in a single actuator, of torque versus angular position characteristics, such as a selectable number of detents per revolution. The actuator is in communication with a servo motor having a position encoder which outputs position information to a controller that has access to torque-position relation information. The controller outputs a digital torque signal, in accordance with the torque-position relation information, which is converted to an analog current signal applied to the servo motor to generate torque in the servo motor. The torque, presenting a tactile response to a human interacting with the actuator, is sensed as a detent or a plurality of detents.

Abstract: An electromagnetic drive system includes a motor having a first motor section movable relative to a second motor section along a motion axis. The second motor section has three excitation coils. The first motor section includes a magnetic circuit generating a magnetic field in the excitation coils. The first motor section also includes a short-circuit winding for only high-frequency induction currents. This short-circuit winding is magnetically coupled to the excitation coils. The degree of electromagnetic coupling of at least one excitation coil depends on the position of the first motor section relative to the second motor section. The short-circuit winding provides a position-dependent electromagnetic coupling between the center excitation coil and the two outer excitation coils.

Abstract: Displacement measuring apparatus for measuring the displacement and movement of an object includes an array of sensors having an operative surface and circuitry for producing an electrical output signal whose value is dependent upon the disposition of an electrical/magnetic field producing member along the sensor array. The field producing member is disposed to contact and slide over the operative surface as the object whose displacement is to be measured is moved. The value of the electrical output signal produced by the circuitry is thus dependent upon the position of the field producing member along the sensor array and thus by the position and movement of the object.

Abstract: A magnetic head and disk tester which has linear encoders (40 and 42) installed on lateral sides of a carriage (30) which carries a magnetic head (34), movable in a radial direction along a hard disk. Positions of the magnetic head with respect to the hard disk are measured by means of the linear encoders which are arranged on both lateral sides of the carriage. Outputs of the encoders are supplied to an arithmetic unit (45) which calculates the arithmetic mean of the encoder's outputs and transmits the resulting signal via a feedback line (47) to a piezoelectric translator (37). The translator is the final drive element in the carriage-drive system and is used for fine positioning of the carriage. Thus, if during positioning of the magnetic head the latter is installed in an erroneous position, e.g.

Abstract: A datuming device is provided for use with a machine tool having a movable member which is guided under computer numerical control. The datuming device permits measurement of displacements in a direction not parallel with a displacement probe's line of travel. The device includes a non-sensitive surface which, when probed by the displacement probe, does not indicate a changing displacement when the movable member is moved from a first position to a second position. The nonsensitive surface serves as a reference surface. The device further includes a sensitive surface which, when probed by the displacement probe, exhibits a changing displacement when the movable member is moved from the first position to the second position. The sensitive surface is generally configured as an inclined surface on the datuming device.

Abstract: In a servo system using a discrete signal relative to a position, a time delay and an error upon detecting a speed due to lack of positional information are eliminated to achieve a positioning to a target position in a short time. A pulse signal X.sub.P relative to a position is used to establish synchronization with an observer which is adjusted to match with an actual apparatus comprising a load, a motor and so on, and an estimated speed value or an estimated position value generated by the observer are used to determine an operating signal for the servo system.

Abstract: A self-adjusting motor positioning system comprises a motor including a shaft extending therefrom, a disc coupled to the motor shaft and having at least first and second notches, rotating apparatus coupled to the motor shaft whereby the rotating apparatus is intermittently driven by the motor, a sensor adjacent the disc for detecting the first and second notches, and a control processor coupled to the sensor and the motor for receiving detection signals from the sensor and for turning the motor on and off. The control processor includes memory for storing a time delay count representing a time delay for the control processor to turn off the motor after the second notch is detected by the sensor. The rotating apparatus includes a starting position from which the rotating apparatus begins. The first notch in the disc corresponds to the starting position of the rotating apparatus. The control processor turns the motor off when the time delay expires after the sensor detects the second notch.

Abstract: A monolithic interface circuit for use with a linear variable differential transformer (LVDT) position transducer. The interface circuit includes a drive circuit for providing an excitation signal of selectable frequency and amplitude to the LVDT primary winding. The interface circuit further includes a decoder responsive to signals induced in the LVDT secondary windings for computing the position p of the LVDT core as a solution to the equation p=K(A-B)/(A+B), where A and B represent the signals induced in the primary winding and K is a constant scale factor. The decoder includes circuitry for rectifying and filtering the secondary signals, a charge balance loop responsive to the detected signals for providing a binary signal having a duty cycle representative of B/(A+B), and an output circuit responsive to the binary signal for providing the position output. The decoder provides excellent scale factor stability and linearity and is relatively insensitive to variations in primary drive amplitude.

Abstract: Displacement measuring apparatus for measuring the displacement and movement of an object includes a sensor having an operative surface and circuitry for producing an electrical output signal whose value is dependent upon the area of the operative surface covered by an electrical/magnetic field producing member. The apparatus also includes an elongate, flexible band capable of producing an electric/magnetic field, where the band is attached at one end to the sensor to roll over and cover or unroll from over and uncover the operative surface as the object whose displacement is to be measured is moved. The value of the electrical output signal produced by the circuitry is thus dependent upon the area of the operative surface covered by the band and thus by the position and movement of the object.

Abstract: A generating device of a phase current instruction value for an A.C. servomotor and the generating method thereof, drives a synchronous A.C. servomotor. A sine wave, namely, a phase current instruction value for commutation of the A.C. servomotor driver can be generated by receiving as an interrupt the detection signal of a commutation sensor which detects the reverse electromotive force of the a motor at the microprocessor. The pulse position of the present since wave is.The pulse position of present sine wave is determined by the interrupt signal of the microprocessor. The motor is driven and controlled by converting by way of a D-A converter to an analog signal the data for generating a sine wave according to the increase or decrease of an encoder pulse.

Abstract: Where T.sub.1 is a period of a dynamic operation range of a phase comparative waveform of a motor servo apparatus, and a period T.sub.0 of a reference phase signal is measured, the reference phase signal is delayed by T.sub.3 =T.sub.0 -T.sub.1 /2 to obtain a gate signal. The dynamic operation range is started by the gate signal. Thus, the operational center of the phase system is brought in line with the dynamic operation range. The operation is made symmetrical in the dynamic operation range to achieve a rapid servo lock and a stable phase control over the motor servo apparatus, even at the start of the motor or when an external perturbation occurs.

Abstract: An actuator having electronically controllable tactile responsiveness which is flexibly programmable to facilitate provision in a single actuator of torque-position characteristics, such as a selectable number of detents per actuation through its full operative path. A rotary actuator facilitates provision in a single actuator, of torque versus angular position characteristics, such as a selectable number of detents per revolution. The actuator is in communication with a servo motor having a position encoder which outputs position information to a controller that has access to torque-position relation information. The controller outputs a digital torque signal, in accordance with the torque-position relation information, which is converted to an analog current signal applied to the servo motor to generate torque in the servo motor. The torque, presenting a tactile response to a human interacting with the actuator, is sensed as a detent or a plurality of detents.

Abstract: A position-controlled actuator includes a motor supplied with power by a power supply circuit controlled at least by an error signal. A speed reducer converts rotary movement of the motor into linear movement over a given travel. An output sensor indicates the position of the actuator and an error signal computation circuit compares a commanded position of the actuator to a calculated position. The output sensor supplies a binary position signal taking two different values according to the position of the actuator relative to its mid-travel position.

Abstract: A method of determining the rotational speed of a three-phase brushless DC-motor, which comprises scanning at least one signal trace disposed on a revolving rotor of a three-phase brushless DC-motor by means of three sensors, each emitting a signal having two possible signal states, the signal trace and the sensors being of such construction and arrangement that eight values are realized by a logical combination of the two possible signal states, respectively, of the three sensors; detecting the rotor position with six of the values; and determining the rotational speed with the other two values.

Abstract: A rivetting machine has a hydraulic cylinder connected with a hydraulic power source, the cylinder including a piston shaft, a motor-driven spindle extending through and journaled to the piston shaft, and a rivet head forming tool secured to the bottom end of the spindle and carrying a forming shaft. A controller of the machine has a linear encoder for detecting the axial position of the piston shaft, an electric hydraulic servo valve provided in a hydraulic circuit between the hydraulic power source and the hydraulic cylinder, a machining data input unit for inputting machining data of the work rivet into a programmable control unit. The control unit receives the output of the linear encoder and the input machining data and controlling the hydraulic cylinder via the electric/hydraulic servo valve based on the machining data and the output of the encoder.