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 control for brushless motors having polyphase moving coil armatures, sinusoidal commutation, and integral linear hall effect commutation sensors providing a correction signal such that the sum of the squares of the commutation signals is maintained at a predetermined constant. A sum squared correction means is used to provide an error correction signal feedback to magnetic field sensors or hall effect commutation sensors used to provide a sinusoidal commutation signal for each phase of a three phase moving coil armature such that the sum of the squares of each signal representative of the commutation signal is forced to be a predetermined constant. This has the effect of substantially reducing the motor force or torque variations typically occurring with such brushless electric motors having sinusoidal commutation. The motor force or torque variations are due in part to the hall effect sensor or magnetic field sensor gain and offset errors.

Abstract: A method of measuring the distance at closest approach between the piston of a free piston compressor and the cylinder head. The method derives measurements of both the alternating and average components of piston position from direct measurements of the voltage and current applied to the linear permanent magnet motor that drives the piston, and thus eliminates any requirement for an additional position sensor located within the compressor.

Abstract: A precision drive assembly for producing constant accurate angular motion of an instrumentality about an axis and which includes a lead screw and a nut threaded to the lead screw. The lead screw is driven by a motor. A radial (tangent) arm is coupled in one end to the nut and at the other end to the instrumentality so that linear movement of the nut along the lead screw causes the radial arm to turn the instrumentality about its axis. Position-rate errors inherent in the drive assembly are corrected by mechanical cam means, or by electric/electronic drive means motor.

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: The oscillatory spring movements of each wheel of a motor vehicle suspension system are damped by a switched reluctance machine which is actively controlled during standard suspension operation to define damping characteristics of the suspension or passively controlled to define a fail-safe damping rate in the event of failure within the system. The switched reluctance machines of a suspension system are selectively connected to standard control circuitry or fault control circuitry by relay contacts. Upon failure within the system, phases of the switched reluctance machines are charged via monopulsers which are controlled in response to rotational positions of the machines such that the machines operate as generators and withdraw energy from the suspension system and pass it to a parallel connected resistor and capacitor.

Abstract: In order to improve a device for the non-circular machining of workpieces comprising a machine frame, a workpiece spindle held on the machine frame and operated as C-axis for a workpiece to be machined, a Z-slide displaceable on the machine frame in the Z-direction in relation to the workpiece spindle and having a Z-axis drive, an X-axis drive in the form of a linear motor arranged on the Z-slide for advancing a tool in the X-direction towards the workpiece, and a numerical control system for activating the X-axis drive in correlation with the rotation of the workpiece spindle, such that more precise work results are obtained, it is proposed that the linear motor serving as X-axis drive be a three-phase asynchronous linear motor with a primary part fixedly arranged in the X-direction on the Z-slide and a secondary part movable relative to the primary part.

Abstract: Control method and apparatus for a moveable control member with n observed states, the apparatus incorporating a sliding mode control system, operable to maintain the state point of the moveable member on a predetermined hyperplane having n-1 dimensions, and comprising digital processor means operable to reference, at a first frequency, n-1 low order observed states to the predetermined hyperplane to establish a desired value of the highest order observed state, the control system further comprising comparator means operable to compare, at a second frequency, said desired value with the observed highest order state, the first frequency being less than the second frequency, and means responsive to the comparator means and operable to implement the control action necessary to maintain the state point on the predetermined hyperplane.

Abstract: In order to obtain a manipulator using a plane pulse motor showing advantageous features such that even in a case where a moment of force is applied to the manipulator in a falling direction, the moment can be sustained by magnetic attraction caused by the pulse motor, the weight of the manipulator is reduced, the degree of freedom of the movement can be increased, and a rotating mechanism for a tool itself is eliminated; a plurality of movable members are provided on a stator of the plane pulse motor, a rotatable shaft is provided on each movable member so as to extend vertically, the rotatable shafts are connected with each other through a connecting member, a required tool is secured to the connecting member, and the movements of the movable members are made controllable in a manner correlated with each other. The manipulator using the plane pulse motor of the aforementioned construction is most adapted to be used in combination with an industrial robot and the like.

Abstract: A real time straightness deviation measuring and compensation device for a machine tool that automatically and continuously compensates for bed way deviation from a truly straight line relative to a workpiece. A wire, parallel to the workpiece or axis of workpiece rotation and perpendicular to the direction of machine tool compensation is utilized as a straightness reference, with the wire being stretched in the direction of machine tool carriage travel and supported on either end by weights for gravity induced straightness. A position indication device, such as a laser micrometer, is attached to the machine tool carriage and positioned around the reference wire in order to read the position of the wire relative to the machine tool carriage during real time operation. An electronically controlled servo motor attached to a machine tool supported on the carriage automatically adjusts the machine tool to compensate for carriage deviation caused by bed way deviation relative to the straight reference wire.

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 controller for a linear induction motor primary includes sensors to measure motor operating parameters which allow the thrust developed by the linear induction motor to be determined. In one embodiment, a microprocessor receives the output of the sensors and determines the thrust developed by the linear induction motor. The microprocessor also performs operations to determine an updated supply voltage frequency which will cause the linear induction motor to develop thrust having a magnitude closer to the maximum thrust point of the linear induction motor at the given motor speed if the determined thrust is less than the maximum thrust. The microprocessor monitors the output of the sensors continuously so that the supply voltage frequency is updated continuously. This permits the linear induction motor to develop thrust near to or at its maximum thrust point regardless of changes in the ambient temperature or the linear induction motor secondary characteristics at any given speed.

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 control mechanism for an optical system wherein a scanning operation by an optical system is controlled by the amount and the direction of an electric current supplied to an optical system drive motor; and wherein a current limiter value modifying means for changing a current limiter value which stipulates a maximum current value for the optical system drive motor is provided which sets a smaller current limiter value during control of a return scan by the optical system than the current limiter value set during control of a forward scan by the optical system.

Abstract: A five degree-of-freedom positioning device includes a manipulator shaft for manipulating an object to a desired position and orientation. Two sets of stator permanent magnets are spaced along an axis of the manipulator and arranged in parallel planes transverse to the manipulator axis so as to provide therebetween magnetic fields substantially extending along the axis. Interposed between the sets of permanent magnets are axially spaced sets of electrically energizable coils also arranged in parallel transverse planes. The coils are energized to produce coil fields that interact with the magnetic fields of the permanent magnets for generating the Lorentz force which acts on the manipulator shaft to effect two translational movements of the manipulator shaft along two mutually orthogonal axes perpendicular to the manipulator shaft axis and three rotational movements about the three mutually orthogonal axes including the manipulator shaft axis.

Abstract: The invention discloses an Ultrafast Electro-Dynamic X, Y and Theta Positioning Stage. A positioning stage made according to this invention allows light payloads to be moved with extremely high linear and angular accelerations over finite distances and angles with a plane. An important feature of this invention is a momentum-cancelling design which allows reaction forces and torques on the fixed member to approach zero, thereby, allowing for a smooth and an ultrafast performance by the positioning stage.

Abstract: A positioning system for accurately positioning components and the like in which a two-dimensional linear motor moves upon an air bearing across a large platen having a predetermined grid pattern yielding reasonably good resolution. A second two-dimensional positioning assembly of extremely fine resolution is secured to the linear motor arranged to traverse the large platen. Location sensors are provided in closed loop feedback system for detecting the X and Y positions. Coarse resolution is obtained by operating the first two-dimensional linear motor and fine resolution is obtained by operating the second two-dimensional positioning assembly, preferably after disabling the air bearing. The fine positioning system may also include a driver motor for rotating a manipulator arranged upon the second positioning system to correct for any angular misalignment of the component being placed by the manipulator.

Abstract: A brushless DC linear motor includes a coil unit in which electric flow terminals of each of three flat coils are connected with a star connection or with a delta connection; and the three flat coils have the same shape whose empty core section and winding section have their dimension of breadth determined on 1/2 of a magnetic pole-pitch of a magnetic body and are arranged in a shifted position of the magnetic pole-pitch by n/3 (n is a natural number excluding multiples of 3) on the coil unit. The motor also includes a sensor unit in which three magnetic detection sensors corresponding to the respective flat coils are arranged at intervals of 1/3+2m (m=0, 1, 2, 3, . . . ) of the magnetic pole-pitch and any of these magnetic detection sensors and its corresponding flat coils are arranged at the determined distance in accordance with the magnetic pole-pitch.

Abstract: The drive control apparatus for a linear actuator according to the present invention uses fine actuators, such as an electrostrictive element, so that it is possible to manufacture a linear actuator drive control apparatus obtaining big driving force in spite of a size considerably smaller than the conventional magnetic motor and linear motors utilized electromagnetic force. In addition, since the fine actuator and the driving base repeats their fixings and seperatings, it is possible to make the driven stroke range of the driving base wide. Since the fixing operation and the separating operation are carried out when the speeds of the fine actuator and of the driving base are almost the same, generation of the shock due to sudden speed change of the fine actuator and the driving base at the same of their fixing and separating is prevented, and it is possible to obtain smooth driving of the driving base.

Abstract: The linear drive motor is based around a proportional solenoid L1, to which is connected a velocity transducer F1. The velocity output of the transducer F1 is compared to a reference voltage V1 by an error amplifier/driver A1, which in turn drives the solenoid L1. This gives velocity control to the linear motor, without the usual disadvantageous rotary to linear conversion mechanisms. The linear motor therefore has a higher bandwidth, and is free from mechanical vibrations and resonances, and from backlash.

Abstract: Stable compliance control at a high speed is achieved by cooperation between a manipulator and a wrist body which is located at the end of the manipulator arm.

Abstract: Disclosed herein is a linear actuator for controlling the movement of a payload along a linear trajectory. Such actuator is particularly useful, for example, in controlling the radial position of a write/read head in an optical or magnetic recorder/player. The actuator comprises a simple elongated ferromagnetic member, preferably having a substantially triangular cross-section. Such member is surrounded by a coil to which a payload-bearing carriage is rigidly connected. Bearing devices are provided for slidably mounting the carriage for movement on and along the ferromagnetic member. A plurality of magnets serve to establish a magnetic field through which the coil, upon applicaiton of a current, is advanced along the ferromagnetic member. The ferromagnetic member serves the dual function of conducting magnetic flux and guiding the payload along the linear trajectory.

Abstract: A linear driving device is used for example in a copying apparatus. The linear driving device has a first and second linear driving section. The sections can displace a drum projection optical mechanism and an original document scanning optical mechanism from respective initial positions alternately in an original document scanning direction. A driving control section imparts a speed pattern for the drum projection optical mechanism and the original document scanning optical mechanism so that a speed ratio is at 2 to 1. The control section also controls the first and second linear driving sections according to the speed pattern. There is an initial position adjusting section for independently controlling the respective first and second linear driving sections according to external instructions, apart from the control to be effected by the driving control section. The initial position adjustment section compensates for errors caused during assembly or wear in order to keep an optical path constant.

Abstract: In a linear motor comprising a moving body and a plurality of electromagnets arranged along the path of the moving body, the electromagnets are divided into blocks, each block comprising one or more electromagnets which are energized simultaneously. The blocks are energized sequentially with the time lag between energizations of sequentially energized blocks being sufficient to allow the current in each block to reach substantially its steady state level before the next block is energized. When starting the linear motor, a first block is energized, and a transient state occurs in which the current drawn by the first block is higher than the steady state current drawn by the first block. At the end of the transient state of the first block, a second block is energized. Third and fourth are energized similarly, each block being energized only when the transient state of the preceding block is substantially over, i.e. when the current drawn by the preceding block is substantially at its steady state level.

Abstract: A driving apparatus for smoothly driving a running unit of a robot, including a movable table movably supported by first and second gear mechanisms driven by independent first and second motors engaging with respective two parallel racks to carry a robot body.

Abstract: There are disclosed both one and two-dimensional, high resolution, brushless DC servomotors that are linear, rotary, planar and cylindrical in nature. All of these employ a capacitive method for deriving the required position and motor commutation information. In suitable circumstances, particularly two-dimensional planar motors on air bearings, the method allows the use of the motor ferromagnetic cores themselves as the capacitive position sensing elements. This leads to a particularly simple and compact type of sevomotor design. In addition, since such motors can move at high speed, there are also disclosed two transformer coupled methods for handling the current drive to the motor windings. Both methods are simple, energy efficient, applicable to motors of any number of phases, and in addition, handle motor direction reversals automatically.

Abstract: A load driving circuit for supplying a load current proportional to an input signal to drive an impedance load. The load driving circuit includes a current detecting circuit for generating a load current signal representing a magnitude of a load current flowing through the impedance load, a voltage supply for producing a voltage signal corresponding to a difference between the load current signal and the input signal and for supplying the voltage signal to a first end of the impedance load, and an inverting voltage supply for inverting the voltage signal and for supplying an inverted the voltage signal to an opposite end of the impedance.

Abstract: A flight motion simulator includes a unit under test supported on a stationary frame for angular and translational movement along pitch, roll, and yaw axes. A rotor element is secured to the unit under test and has a spherical configuration. Magnetic bearings supported by the stationary frame support the rotor element in three degrees of freedom of movement. A drag-cup induction motor is mounted on the frame and connected to the unit under test to generate three degrees of freedom of movement by generating a rotating magnetic flux in a stator assembly to induce a corresponding flow of currents in the rotor element to produce torque and motion in the unit under test in the same direction as the flux movement in the stator assembly.

Abstract: A control system for a reciprocating linear motion or intermittent motion device. The system includes e.g. programmable control for setting an extent of stroke for an operation member of the device, for setting a period of stroke time for the operation member, and a memory for storing therein in the order of addresses items of velocity data at stroke positions at a specified spacing, the items of velocity data being obtained from a predetermined operation member velocity diagram. When the extent of stroke and time are specified by, the velocities of the operation member are determined based on the specified values and the velocity data in the memory, permitting the operation member to perform a stroke motion by the specified amount for the specified time period at the velocities determined.

Abstract: A gyroscope erection system uses an electrolytic tilt transducer (21) to modulate oscillator signals (OSC, OSC) originating from a signal conditioning circuit (27). The signal conditioning circuit (27) receives the modulated oscillator signal and compares one unmodated oscillator signal with the modulated oscillator signal from the tilt transducer (21), to provide a demodulated signal. The demodulated signal is used to provide direction and amplitude signals to a pair of multipliers (45, 47). Output from the multipliers (45, 47) are amplified in order to drive a torquer (25).

Abstract: A drive arrangement is described, comprising a multi-phase synchronous motor whose phase windings are energized with energizing currents whose strengths are periodic functions (f1, f2, f3) of a rotor-position or translator-position measurement value (p) which is determined by means of an incremental detection system. The drive arrangement has means for adjusting the initial position-measurement value (p) before the motor is energized with the periodic energizing currents. For determining the initial value, the phase windings are energized in different consecutive time intervals (T) with measurement alternating currents (im1, im2, im3) whose amplitudes are equal to K times the function values (f1, (ROPOS), f2(ROPOS), f3(ROPOS)) of the periodic functions (f1, f2, f3) associated with different auxiliary values (ROPOS). The frequency and amplitudes are selected in such a way that the rotor or translator performs a vibration whose vibration amplitude corresponds to only a few electrical degrees.

Abstract: Selective compliance in up to six degress of freedom in a magnetically levitated fine motion device, or robot wrist, with limited motion in X,Y,Z, ROLL, PITCH, YAW, is provided by controlled actuation currents applied to six electrodynamic forcer elements. The wrist has a stator support base defining a dual periphery, carrying a number of stator magnet units. A shell flotor unit nests within the stator support base dual periphery, and carries forcer coils at locations corresponding to respective magnet units. The magnet unit and related flotor coil form a forcer element. There are a number of forcer elements. The vector sum of all the translational forces and rotational torques established at the forcer elements determines the X,Y,Z, ROLL, PITCH, and YAW motion of the flotor. The flotor carries an end effector which may be a tool. Position and orientation of the flotor is monitored by light emitting diodes and lateral effect cells.

Abstract: In a speed control system for a carriage movable along a predetermined path, light beams originating at the ends of the path are deflected by light conductors aboard the carriage so that they are interrupted, as the carriage moves, by a slotted plate extending along the path. The light beams are then deflected by light conductors so that they are directed along the carriage path to light receivers situated at the ends of the path. Electrical pulses from the light receivers are ORed together and converted by a transducer to a signal representative of the actual carriage speed, and by a counter to a signal representative of the carriage position. The carriage position signal is converted, in accordance with a predetermined functional relationship, to a speed set signal which is compared with the actual carriage speed. A signal, representative of the difference between the actual speed and the set speed is used to control the driving motor for the carriage.

Abstract: A data recording disk file with a voice coil motor (VCM) actuator and a digital servo control system for positioning the read/write heads to selected concentric data tracks includes means for calculating the factor relating acceleration of the heads to VCM input current. This permits each disk file to compensate for any variation in the nominal VCM physical parameters, thus enabling VCMs to be manufactured to less demanding tolerances. The disk file also calculates a unique acceleration factor for each head position during movement of the heads from one track to another, thereby improving the arrival time of the heads to the target track. During an initialization procedure, the disk file performs a track seek, during which VCM current and head velocity information are acquired and used by the microprocessor in the digital servo control system to calculate a value representing an average actual acceleration factor unique to that disk file.

Abstract: An assembly is described for accurately and precisely controlling the position of a plunger in a syringe to deliver precise fluid volumes. The assembly includes a motor coupled to a lead screw that drives a bearing block along a linear guide rod to move the plunger of the syringe in a linear fashion. The position of the plunger is accurately controlled by attaching a digital encoder to the rotating motor shaft. The encoder and associated electronics output to a controlling processor that generates a series of regular pulses, typically 300 to 500 responsive to each motor revolution. Utilizing appropriate gear ratios of the motor and the lead screw, the number of pulses per full syringe stroke in typical applications can be on the order of one hundred thousand. The final position and the motion of the plunger (velocity and acceleration) can be controlled to within a few encoder pulses, thus precisely controlling the rate of delivery of the fluid and the volume of the fluid actually delivered by the syringe.

Abstract: A transporting system of floated carrier type including a guide rail having a bottom surface portion formed of a ferromagnetic material, a carrier arranged to be freely movable along the guide rail, at least one magnetic supporting unit placed on board the carrier and including electromagnets arranged so as to face the bottom surface portion of the guide rail via gap and a permanent magnet that is placed in the magnetic circuit formed by the electromagnets, the guide rail, and the gap, for supplying magnetomotive force required for floating the carrier. A sensor section is attached to the carrier for detecting changes in the magnetic circuit. The length of the gap is controlled by a zero power feedback loop that stabilizes the magnetic circuit in a state in which the current flowing in the electromagnets is zero, by controlling the exciting current in the electromagnets based on the output of the sensor section.

Abstract: A two-dimensional linear motor is provided with sensors respectively capable of detecting only the x and y grid lines arranged in a platen traversed by the linear motor. These signals are accumulated and their counts are compared against the respective x and y distances the linear motor is to be moved in order to move the linear motor to the precise position desired and/or to verify that the desired movement has been accomplished. Differentiation of the mutually orthogonal sets of grid lines is accomplished by providing the grid lines with reflective surfaces which have different reflectivity characteristics or alternatively have a different reflectivity characteristics at with appropriate evaluation devices such as filters or threshold circuits which differentiate between either different wavelengths or different reflectivity characterisitics.

Abstract: A control apparatus for a linear motor includes a linear motor having a moving coil to be moved in response to a drive signal, a position detector for generating a present position signal representing a present position of the moving coil, a target position setter for generating a target position signal representing a target position of the moving coil, a position deviation detector for generating a position deviation signal representing a difference between the target position signal and the present position signal, an inclination angle detector for generating an inclination angle signal representing an angle between a moving direction of the moving coil and a horizontal plane of the earth, a control instruction circuit for amplifying the position deviation signal with characteristics corresponding to the magnitude of the inclination angle signal, and for generating a control instruction signal, and a driver circuit for generating the drive signal corresponding to the control instruction signal.

Abstract: An apparatus for actuation of a setting element has a desired value transmitter and an actual value transmitter for the deflection of the setting element from a rest position. The apparatus includes an electronic controller, particularly for a motor vehicle, wherein the deflection of the setting element is proportional to an electric current fed to the element by the controller. An operating mode of the controller is provided by which a signal emanating from the desired value transmitter is converted into a current proportional to a desired value.

Abstract: A reciprocatable shuttle employed to advance a variable number of article carriers through successive work stations is driven on forward and return movements by a plurality of energizable linear motor stators for which the shuttle forms a common reactor. Energization of the stators is controlled by a programmable logic contoller in response to inputs from velocity measuring circuits which determine the difference in the actual velocity of the shuttle relative to a desired maximum forward velocity, return velocity and creep velocity; to inputs from distance measuring curcuits which determine the distance travelled by the shuttle relative to a forward deceleration point and to a return deceleration point; to inputs which establish the return or forward position of the shuttle; and, to inputs which count the number of article carriers to be advanced.

Abstract: A nonlinear control system adapted to drive and control the speed, stroke, phase and center position of a reciprocating linear motor by means of phase locked loop techniques and the electromechanical filtering properties of linear motors. The control system comprises a tri-state switching amplifier in conjunction with 3 distinct feedback control loops to accurately determine the amplitude, center position and phase of the motor. The first feedback control loop includes a low pass averaging circuit and compares the motor position with a reference signal to achieve the desired motor position. The second feedback control loop includes a peak detector and determines the stroke of the reciprocating motor. The third feedback control loop operates as a phase locked loop to control the phase of the motor. The control system provides high efficiency, high reliability and low cost.

Abstract: A rod member provided with magnetic and non-magnetic portion arranged alternatingly is provided and a plurality of detecting heads for detecting magnetic resistance are disposed along the longitudinal direction of the rod member with predetermined distances, respectively. The pitches of the respective pairs of the magnetic and non-magnetic portions are arranged with pitches different with each other by the predetermined distances. Output signals transmitted from the detecting heads in accordance with the relative movement between the rod member and the detecting heads are detected by phase detectors, and on the basis of the detected signals, the predetermined operation is carried out in an operation processing unit thereby to obtain the absolute positional relation between the rod member and the detecting heads in, for example, of a positioning system such as in a die casting machine.

Abstract: A movable table system comprises a base horizontally mounted on a foundation with an intermediate base engaged with the base through first guides so as to be movable reciprocatively in one linear direction. A movable table is engaged with the intermediate base through second guides similar to the first guides so as to be movable reciprocatively in the same linear direction. A direct-acting type drive is interposed between the movable table and the intermediate base for providing relative movement between the table and the intermediate base. Preferably, the base is mounted on the foundation through vibration absorbers.

Abstract: The device comprises two pick-up elements which can cooperate independently with a transmission line for control signals and are aligned in the direction of movement of a conveyor unit so as to be positioned respectively upstream and downstream in the direction of movement of the conveyor unit. The two pick-up elements are separated by a distance such that, during traversal of the gaps between successive sections of the line, at least one of the two pick-up elements is able to receive signals from the transmission line. A signal treatment circuit generates selectively an output control signal corresponding either to the single signal received by the two pick-up elements or to the control signal received by the pick-up element in the position upstream relative to the direction of movement of the conveyor unit when the pick-up elements receive different signals.

Abstract: An improved gas bearing X-Y-.theta. stage assembly is disclosed which has a base, a stage element with three retroreflectors fixedly mounted thereto, and a control system for controlling the movement of the stage element. The control system is made up of three interferometer measuring systems for measuring parameters associated with changes in position of the three retroreflectors as the stage element moves. Also, the control system includes a transport system for moving the three interferometers to maintain optical coupling between the interferometers and retroreflectors. In addition, the control system includes control circuitry for causing the stage element to move to a preselected X-Y-.theta. position in response to signals from the interferometer measuring systems.

Abstract: In a sensor having a drive winding for establishing a forward field, an electrically conductive screen is displaceable relative to a sense winding. In the presence of the drive field, eddy currents are generated in the screen to establish a counter-field opposing the forward field, so that the sense winding is shaded by the screen to a varying extent during relative displacement of screen and sense winding and the voltage induced in the sense winding is accordingly correspondingly varied. Application of a high frequency input to the drive winding results in a modulated output from the sense winding which may be demodulated to provide a signal indicative of screen position relative to sense winding. The position signal may be further processed to provide a speed signal. The sensor may assume a multiplicity of linear or planar, rotational and axial or solenoidal configurations.

Abstract: An actuator drive circuit for driving a load using a single power supply. The current drive is not dependent on load impedance characteristics. Drive means provides a voltage across the first terminal and the second terminal during at input signal positive phase, and reverse voltage across the first terminal and the second terminal during a negative phase. A current detection resistor is connected in series with the load, and the voltage across the resistor is input to a differential amplifier. The amplifier output provides feedback to the drive means.

Abstract: A magnet controller for a magnetically suspended vehicle of the linear stator type for travelling along a rail track (1) forming a linear stator having teeth of uniform determined width, responds to a rectified control signal. The control parameters for the magnet controller (21) are adjusted in response to speed to assure a stable control during standstill and at low speeds and to achieve a good response or follower characteristic of the control system at high speeds. A speed representing signal (U.sub.v) is generated in a conductor loop, preferably a double loop (9), inserted into a groove (10) of the poles (5) of the levitation magnets (2). The signal (U.sub.v) generated in the conductor loop is rectified at (31), and if desired passed through a low-pass filter (32) to provide the control input signal for the controller (21) by a very simple circuit. Utilizing just the amplitude of the speed signal (U.sub.

Abstract: A turning machine is characterized by a new and improved control and mechanism for positioning the turning tool on the head. A CNC control issues command signals for selectively positioning the tool on the head. These signals are developed from an encoder which provides the instantaneous position of the rotating part being turned and from a program in the CNC containing information about the part. A closed loop control system receives these command signals and converts same into a control current for a linear motor which is the prime mover controlling the positioning of the tool on the head. The linear motor operates a carriage on the head and the cutting tool mounts on the carriage opposite the connection of the linear motor to the carriage. The carriage is a hollow bar guided on the head by sets of rollers which are cooperatively arranged to provide yieldably forceful constraint of the bar.

Abstract: An electro-mechanical actuator has a ferrous alloy armature movably mounted within a body chamber. Two axially-spaced permanent magnets are arranged radially inwardly of the chamber and partially define the chamber at the ends thereof. A coil surrounds the chamber. The body is formed of a magnetically-permeable material. Because of the high reluctance of the magnets, each magnet forms a short magnetic loop which passes through the adjacent air gap, and forms a long magnetic loop which encircles the coil and passes through the distant air gap. The armature has a bistable toggle-like movement, and may be latched proximate either end wall. If springs are added between the armature and the body, the improved actuator may be used as a proportional position of force transducer within an operating range of armature movement.