Abstract: A positioning servo controller is provided in which optimization of the positioning state can be conducted simply by adjusting an adjustment gain. In a positioning servo controller with: a speed feedforward controlling section (22) which sets a value that is obtained by adding a first feedforward compensation amount to a position deviation, as a speed command; an acceleration feedforward section (23) which sets a value that is obtained by adding a second feedforward compensation amount to a speed deviation, as an acceleration command, the second feedforward compensation amount being obtained by amplifying a differential value of the first feedforward compensation amount; and a torque amplifier (3) in which an acceleration deviation is used as a torque command, and which drives a controlled object on the basis of the torque command, the values of the first feedforward gain and the second feedforward gain are values of functions in which the value of the adjustment gain is used as an argument.

Abstract: A force-applying input device has a controller which calculates a torque component of an actuator drive signal corresponding to a current position by multiplying the sum of the current position and the product of a current speed and a coefficient by an elastic modulus. In addition, the controller also calculates a torque component of the actuator drive signal corresponding to the current speed by multiplying the current speed by a coefficient of viscous friction.

Abstract: In an actuator having an integrated drive circuit, a switching current flowing in a coil within the actuator is included in a position sensor signal of the actuator. According to the present invention, by arranging a detection circuit which performs sampling in synchronization with noise, a rotational position which does not include higher harmonic waves can be detected even if the switching noise in a motor coil current in the actuator itself is generated. Consequently, elimination of the influence of the noise allows posture and position control with less vibration to be realized.

Abstract: The invention relates to an actuator (22) for a seat, of the type comprising, on the one hand, a body (40) and a control element (38) displaceable relative to the body (40), under the control of an actuating motor (36), and, on the other hand, a transducer (42) disposed between the body (40) and the control element (38), said transducer (42) being suitable for providing a raw measurement value representative of the current position of the control element (38) relative to the body (40). It has a unit (46) for correcting said raw measurement value, said correction unit (46) being suitable for implementing a correction algorithm which is specific to said actuator and which is suitable for providing a corrected value for the current position of the actuator on the basis of said raw measurement value. Said correction unit (46) is specific to said actuator and is integrated therein.

Abstract: A method for determining the rotational position of the drive shaft of a DC motor includes providing a period of a reference current ripple indicative of proper operation of the motor. The period of the reference current ripple is then compared with the period of each current ripple contained in a rotor current signal of the motor during operation of the motor. The current ripples of the rotor current signal of the motor having periods which differ from the period of the reference current ripple are then corrected. A corrected rotor current signal based on the corrected current ripples and uncorrected current ripples of the rotor current signal of the motor is then generated. The current ripples contained in the corrected rotor current signal are then counted to determine the position of the drive shaft of the motor and, consequently, the position of an element being driven by the motor.

Abstract: A controller capable of preventing response delay and generation of vibrations attributable thereto during position control of a movable part of a machine having low rigidity. A motor for driving a machine having low rigidity is subjected to position and velocity loop control. Compensation amount Q1 proportional to command velocity obtained by differentiating a position command and compensation amount Q2 proportional to second-order differentiated command acceleration are obtained. Compensation amounts Q1 and Q2 are added together, thus obtaining a velocity offset amount Vof corresponding to a estimated torsion amount. A differentiated value of the velocity offset amount is multiplied by coefficient &bgr; to obtain a torque offset amount Tof. The velocity offset amount Vof is added to a velocity command Vcs obtained by position loop control 1. The torque offset amount Tof is added to a torque command Tc outputted in velocity loop control 2, and the result is used as a drive command to the motor.

Abstract: The invention concerns a feed system control method and apparatus that can calculate an accurate backlash amount and can accomplish highly precise position control. Position errors are calculated before and after a reversal in direction of movement of a slide 30, each from the difference between the position data of the slide 30 detected by a linear scale 25 and the position data of the slide 30 calculated from the rotational position data of the servo motor 23 detected by a rotary encoder 24. The backlash amount of the slide 30 is calculated from the difference between the position error before the reversal and the position error after the reversal thus calculated. Thereafter, when reversing the direction of movement of the slide 30, the feed speed during direction reversal is increased in accordance with the backlash amount.

Abstract: Controlling a direct current motor driving an object by determining, if the object does not reach a target position, a reference velocity corresponding to a point of time from a predetermined velocity trajectory, obtaining a position of the object, calculating a current velocity of the object, and calculating a difference between the reference velocity and the current velocity. If the calculated difference is greater than a velocity error limit value, informing a user that an error has occurred.

Abstract: A synchronous position control apparatus includes position controllers which perform control based on position feedback for a plurality of axes to be controlled, target position command value generators for respective axes which generate target position command values to be set in a respective position controller, and converters for respective axes which convert, on the basis of predetermined transfer functions, the target position command values for the respective axes that are output from the respective target position command value generators, and set the converted values in the respective position controllers. The characteristics of the transfer functions are set to substantially the same high-frequency cutoff characteristics for the respective axes, and the cutoff frequency of the transfer function is set to a smaller value than a servo band in any one position controller.

Abstract: A positioning device that includes a pivotable shaft and a pivot drive mechanism, which has a stator and a rotor that moves relative to the stator. A position measuring arrangement includes a first element and a second element that moves in relation to the first element, wherein the rotor and the first element are connected, fixed against relative rotation, with the shaft. The positioning device further includes a bearing unit, wherein, starting at one end of the shaft, first the first element, then the bearing unit, and thereafter the rotor are arranged along the shaft.

Abstract: A positioning servo controller is provided in which optimization of the positioning state can be conducted simply by adjusting an adjustment gain.

Abstract: In an actuator having an integrated drive circuit, a switching current flowing in a coil within the actuator is included in a position sensor signal of the actuator. According to the present invention, by arranging a detection circuit which performs sampling in synchronization with noise, a rotational position which does not include higher harmonic waves can be detected even if the switching noise in a motor coil current in the actuator itself is generated. Consequently, elimination of the influence of the noise allows posture and position control with less vibration to be realized.

Abstract: Motion controlling includes a combining network having an acceleration input for receiving an acceleration signal representative of acceleration of a movable element and a position input for receiving a position signal representative of position of the movable element and an output for providing an inferred position signal representative of an inferred position of the movable element. The network includes a first signal processor for processing the acceleration signal to provide modified acceleration signal, a second signal processor for processing the position signal to provide a modified position signal and a combiner for combining the modified acceleration signal with the modified position signal to provide the inferred position signal.

Abstract: The seat has moving parts, at least one actuator, and a control unit. The control unit comprises: tracking means for tracking the current position of each actuator; and management means for managing the control of each actuator. The management means comprise: computation means for computing the current position of a critical point of the seat; evaluation means for evaluating the current position of each critical point of the seat relative to a boundary; and control means for controlling at least one actuator independently of the control selected by the user.

Abstract: A vending machine includes a gearmotor with feedback control allowing for the determination and control of the axial rotational position of the gearmotor's output shaft. The gearmotor has a DC motor, gear train, at least one rotation sensing mechanism and control circuitry. The rotation sensing mechanism is in operative connection with the output shaft of the gearmotor and/or the armature shaft of the motor such that the feedback provided by the sensor allows the control circuitry to determine the position of at least one of the shafts and, based on that determination, control the output of the motor to either stop rotation or produce additional rotation as necessary to properly dispense product of varying sizes based on pre-programmed data regarding the desired rotation for various products. A method for controlling the dispensing of products in a vending machine is also disclosed.

Abstract: The device is for driving and controlling a rotation motor and a voice coil motor for a hard disk drive system that includes a disk and an arm carrying a read/write head to be positioned with respect thereto. A duty-cycle control loop including a current sensing circuit is connected to the voice coil motor, and an arm position control loop including a speed detection circuit is also connected to the voice coil motor. The duty-cycle control loop and the arm position control loop are digitally implemented by a DSP as a function of digital data representing a first analog signal generated by the current sensing circuit representative of current conducting in a winding of the voice coil motor, and a second analog signal generated by the speed detection circuit representative of an instant speed of the voice coil motor.

Abstract: Two A.C. output signals amplitude-modulated in accordance with two function values (sine and cosine) differing from each other in correspondence to a position-to-be-detected are received from a position sensor such as a resolver. By performing an addition or subtraction between a signal derived by shifting the electric phase of one of the received A.C. output signals by a predetermined angle, and the other received signal, two electric A.C. signals (sin(&ohgr;t±d+&thgr;), sin(&ohgr;t±d−&thgr;)) are electrically synthesized which have electric phase angles (&thgr;) corresponding to the position-to-be-detected and are phase-shifted in opposite directions. “±d” here represents phase variation error caused by factors, other than the position-to-be-detected, such as temperature change.

Abstract: The invention relates to an actuator (22) for a seat, of the type comprising, on the one hand, a body (40) and a control element (38) displaceable relative to the body (40), under the control of an actuating motor (36), and, on the other hand, a transducer (42) disposed between the body (40) and the control element (38), said transducer (42) being suitable for providing a raw measurement value representative of the current position of the control element (38) relative to the body (40). It has a unit (46) for correcting said raw measurement value, said correction unit (46) being suitable for implementing a correction algorithm which is specific to said actuator and which is suitable for providing a corrected value for the current position of the actuator on the basis of said raw measurement value. Said correction unit (46) is specific to said actuator and is integrated therein.

Abstract: A robot calibration system for calibrating a robot and a method of determining a position of the robot to calibrate the robot are disclosed. The system includes an electrical ground defining a return for an electrical circuit. The robot, which is electrically connected to the ground, includes an arm having a tool surface operating within a robot workspace. The system also includes an electrical supply and a detection device. The electrical supply defines a source for the circuit and provides a charge and a reference voltage to the system. The detection device communicates with the electrical supply to detect variations in either the charge, the reference voltage, or both. The system further includes a calibration object. The calibration object is electrically insulated from the ground and is electrically connected to the electrical supply.

Abstract: The invention relates to a method and an arrangement for driving door installations as a function of the presence of person wherein the region of the door installation is continuously observed by at least one videocamera. According to the invention through the videocamera and/or suitable sensors, object motions within the space to be monitored are acquired with an analysis being carried out in conjunction with the video image of whether or not the moving object is a person. If this is the case, its location and/or direction of movement is determined and the door installation is driven as a function thereof. The videocamera is preferably disposed approximately diametrically opposite the door installation with its angle of view being directed as steeply as possible onto the region to be monitored. The videocamera is connected to an electronic image processing device.

Abstract: A search system for a tool. A border cable separates inner and outer areas. A generator feeds the border cable with current, whose magnetic field affects a sensing unit on the tool, and the sensing unit emits signals to a control unit that directs the tool's motion. The current contains at least two components of different frequency. A search cable is placed within the inner area so that it separates a search area, and is fed by a signal generator with an adapted current (e.g., the current direction alternates to be either in phase or out of phase in relation to the current direction in the border cable) so that the magnetic fields in the different areas provide at least three patterns. Accordingly, the control unit can separate the inner, outer, and search areas.

Abstract: An actuator for a device such as a tappet of a valve. The actuator having a thermostatic operating element electrically heated by an electrical heating element, and including an operating piston. A proportional piston stroke regulator detects and controls the position of the operating piston. The proportional piston stroke regulator includes a piston travel detection device, that detects the actual position of the operating piston, connected to a conventional closed-loop controller which compares the measured piston position to a predetermined piston control position entered into the closed-loop controller. Based on the comparison, the closed-loop controller regulates the electrical supply to the electrical heating element.

Abstract: A device for actuating a seat element includes an actuator fitted with a transducer delivering a state information representative of the current position of the actuator and a unit for controlling the actuator which includes a device for registering and for storing several reference state informations each representative of a position of the actuator for an identified position of the element and a device for driving the actuator so as to move the seat element towards several target positions. The control unit is adapted so as, when a movement towards a predetermined target position is commanded, to activate the actuator until the current reference state information delivered by the transducer is equal to the reference state information stored for the position of the commanded element.

Abstract: Hall ICs 23u, 23v and 23w are provided to detect the magnetic fields of magnetic regions 8 of a rotor 9 and are offset in position by an electrical angle of 30° from central positions of a U-phase stator pole 1, V-phase stator pole 6 and W-phase stator pole 2. A driving circuit 21 controls the timing of rotor driving signals that are supplied to respective stator coils for respective phases based upon rotor position signals outputted from the Hall ICs 23u through 23w. For example, in order to rotate the rotor in a forward direction, the driving circuit 21 controls the timing of the rotor driving signals according to a first logic. Similarly, in order to rotate the rotor in a reverse direction, the driving circuit 21 controls the timing of the rotor driving signals according to a second logic.

Abstract: A six degree of freedom force reflecting haptic interface includes three powered axes and three free axes, all of which are tracked so that the position of a user connection element in the work volume can be determined. The interface includes cable drives with polymer composite or metallic cables, automatic cable tensioning devices, and grounded actuator capstans. A nested hub and transfer drive provide a compact, weight balanced interface. User comfort and safety features are also provided.

Abstract: A ball joint gimbal system which provides for a precise line-of-sight stabilization of a gimballed mirror that rides on a ball and its associated support structure. The mirror is positioned by four braided lines. The brained lines are driven by four servo motor with each servo motor being coupled to one of four capstan shafts. Each of the braided lines is wound around one of the four capstan shafts. The braided lines are positioned by optical shaft encoders. The low inertia of the gimballed mirror and the positioning of the mirror by the braided lines result in an extremely accurate and fast scanning optical pointing system. Inertial gimbal stabilization of the line of sight to a target is by a stabilization algorithm utilizing body rate information from body sensors which are components of the missile for providing autopilot and navigation functions for the missile.

Abstract: A resolver system and method is provided for determining the angle position of a shaft. The resolver system includes a resolver having first and second output windings and an input or reference winding spaced apart from the first and second output windings, where either the input winding or the output windings are connected to the shaft. When a drive signal is introduced into the input winding, it generates first and second output signals on the output windings representing the angle position of the shaft. The resolver system of the present invention further includes a processor connected to the output windings for receiving the first and second data signals from the resolver and determining the angle position of the shaft. For generating the drive signal, the resolver system further includes a drive circuit connected to the input winding of the resolver. The drive circuit generates a pulsed drive signal for input into the resolver.

Abstract: A ball joint gimbal system which provides for a precise line-of-sight stabilization of a gimballed mirror that rides on a ball and its associated support structure. The mirror is positioned by four braided lines. The brained lines are driven by four servo motor with each servo motor being coupled to one of four capstan shafts. Each of the braided lines is wound around one of the four capstan shafts. The braided lines are positioned by optical shaft encoders. The low inertia of the gimballed mirror and the positioning of the mirror by the braided lines result in an extremely accurate and fast scanning optical pointing system. Inertial gimbal stabilization of the line of sight to a target is by a stabilization algorithm utilizing body rate information from body sensors which are components of the missile for providing autopilot and navigation functions for the missile.

Abstract: A DC motor drive circuit includes a switching circuit that drives the coils of a small permanent magnetic DC motor. The drive circuit is preferably implemented in an integrated circuit device, such as a silicon CMOS device. Integrated into the same integrated circuit device is a magnetic sensor arranged to detect the position of the permanent magnet as it passes a defined point, or points, in its revolution, and control circuitry to derive the timing waveforms for driving the coils. The integrated power devices for driving the coils are also arranged to limit the rise and fall times of the applied voltages and currents so as to reduce or eliminate the generation of unwanted RFI. Additional circuitry is also integrated into the same integrated circuit device to derive the necessary power to operate the magnetic sensor, the control circuitry and the switching circuitry from the connections between the switching circuitry and the coils so as to remove the need for a separate power supply connection.

Abstract: A method and apparatus for controlling the leveling table of a wafer stage is described. More generally, the invention includes control circuitry for controlling motion of a stage, where the stage is adapted to support a workpiece. The control circuitry measures position in a vicinity of the workpiece. Based upon the measured position, the control circuitry drives the stage toward a target position while accounting for nonlinear dynamics of the stage. The nonlinear dynamics may include inertia, in which case the control circuitry adaptively estimates the inertia of the stage. The nonlinear dynamics may also include tilt due to acceleration or deceleration of the stage, in which case the circuitry adaptively estimates the tilt of the stage. The stage may generally travel in a plane, and the circuitry measures position in a direction orthogonal to the plane. The circuitry may measure the position of the workpiece itself, or the position of an upper surface of the stage.

Abstract: A polyphase switched reluctance machine is controlled by a control system using sensorless position detection. A method of operating the machine at high speeds interrogates every nth phase reference point to allow sufficient time for computations of position to be carried out, where n is an integer greater than one.

Abstract: A guideless stage for aligning a wafer in a microlithography system is disclosed, and a reaction frame is disclosed which isolates both external vibrations as well as vibrations caused by reaction forces from an object stage. In the guideless stage an object stage is disclosed for movement in at least two directions and two separate and independently movable followers move and follow the object stage and cooperating linear force actuators are mounted on the object stage and the followers for positioning the object stage in the first and second directions. The reaction frame is mounted on a base structure independent of the base for the object stage so that the object stage is supported in space independent of the reaction frame. At least one follower is disclosed having a pair of arms which are respectively movable in a pair of parallel planes with the center of gravity of the object stage therebetween.

Abstract: An electronic cam servo apparatus uses a digital servo controller to perform motion equivalent to a mechanical cam. The control apparatus has one data table representing a characteristic of a mechanical cam and utilizes a data interpolation and the first derivative of a cam position profile to determine position and velocity commands to drive a servo motor which performs motion equivalent to a mechanical cam. Alternatively, the control apparatus uses the first cam specific data table to determine the position, velocity and torque/current command to drive a servo motor. The apparatus may additionally use a second data table representing varying cam load to obtain a more accurate torque/current command correction.

Abstract: A magnetic head and disk tester provides accurate positioning of a magnetic read-write head over a magnetic disk by means of a coarse positioning mechanism and a fine positioning mechanism. The coarse positioning mechanism includes a stepper motor, a lead screw, a nut, rear sliders and a housing. The fine positioning mechanism includes a piezoelectric actuator, slides and a carriage. The positioning displacements are along a linear axis, which lies on a horizontal plane. The carriage is connected to the housing via the fine positioning mechanism, which then moves the carriage with respect to the housing. Two pairs of linear encoders are mounted on the carriage about the axis and measure the position of the magnetic read-write head with respect to the magnetic disk. Each pair is mounted such that the pairs lie in separate horizontal planes.

Abstract: An apparatus for determining an incremental angular position of a rotating member of an induction motor. A sensor assembly is positioned adjacent a target wheel attached to the rotating member, the target wheel having a plurality of teeth, separated by slots, angularly spaced around the periphery of the target wheel. The sensor assembly is located proximate the periphery of the target wheel, and includes a plurality of sensors each configured to generate a respective output signal that transitions between first and second states at the passage thereby of each leading and trailing edge of the teeth. The apparatus also includes a processing circuit configured to generate an incremental position signal in response to the output signals. Each sensor is spaced from an adjacent sensor by a predetermined distance equal to 180 degrees divided by n, where n is the number of sensors, and 360 degrees is a tooth-to-tooth distance.

Abstract: The present invention is directed to a method and apparatus which utilizes a software-based digital signal processing circuit to generate a signal which is representative of the status of a movable component. A preferred embodiment of the apparatus of the present invention includes a synchro which is connected to a movable component. An analog reference excitation may be applied to the synchro, and the synchro generates analog synchro signals which bear a relationship to the status of the movable component. The analog synchro signals are converted to digital synchro signals by a plurality of analog-to-digital converters. A digital reference signal and the digital synchro signals are provided to a software-based digital signal processing circuit which preferably corrects constant and time-varying errors in the digital synchro signals and generates a status signal which is representative of the status of the movable component.

Abstract: For enabling precise operation of an oscillating device, such as a galvanometric optical scanner, a capacitive position transducer is provided with strategically located internal capacitive fiducial features that interact with the armature of the transducer beyond the central range of excursion of the transducer, typically beyond the normal operating range of the device. Electric pulses obtained at instants of interaction with the fiducials enable determination of position drift caused e.g. by change in environmental conditions. The pulses can be detected by simple circuits to produce recalibration of the amplitude and null position of the instrument on an automatic or elective basis.

Abstract: A circuit for use with a limited resolution device such as a stepper motor to convert a high-resolution signal such as from a computer into a high fidelity signal for driving the limited resolution device. The input to the limited resolution device being an average of the integrated difference between the high-resolution signal and a limited resolution signal consistent with the values used for driving the limited resolution device. This average being a high fidelity signal which is substantially the same as the high-resolution signal.

Abstract: A control console comprising at least one member (1) for adjusting the level of radio-electric signals capable of taking up any position between two extreme positions, elements for detecting the instantaneous position of the member and elements for memorizing at least one position of the member. This console is characterized in that each adjusting member is provided with both motor mechanism for automatically positioning the adjusting member in its memorized position corresponding to a status of adjustment selected by the user and tactile elements for signalling the deviation ratio of the adjusting member relative to its predetermined memorized position. The invention is useful for mixing or lighting consoles.

Abstract: In accordance with the described invention, a stepper motor that drives a printer's movable subsystem, e.g. a sled-mounted ink-jet service station, is replaced with a less expensive and quieter DC motor, and continuous positional feedback is obtained via a fixed subsystem-mounted optical sensor array in cooperation with a movable subsystem-mounted code strip that includes a home-position encoding region. The code strip produces in the optical sensor array, in reflective response to a fixed subsystem-mounted light source, a plurality of modulated signals as the substantial extent of the code strip passes by, thereby enabling positional tracking of the movable subsystem's motion, and produces a secure home-position identification signal set when the homing patch is in the `view` of the array.

Abstract: A method and system (10) for simultaneous operation of primary (14A-14D) and redundant (16A-16D) motor windings in a redundant stepper motor (12). The redundant motor system (10) has a control circuit (11) including a phase synchronizer (36) for establishing a relationship between predetermined primary and redundant motor windings (14A-14D and 16A-16D) such that the power consumption is increased and the motor torque is affected. In one embodiment of the present invention the predetermined motor windings (14A-14D and 16A-16D) are operated in phase thereby doubling the power consumption and increasing the torque. In another embodiment, the predetermined motor windings (14A-14D and 16A-16D) are operated in phase quadrature thereby doubling the power consumption and increasing the torque by less than 50%. In yet another embodiment, the predetermined motor windings (14A-14D and 16A-16D) are operated out of phase with each other thereby doubling power consumption and producing zero torque.

Abstract: A power window apparatus is provided for detecting pinching in accordance with the opened/closed position of the window and a state of rotation of a motor, the apparatus having a position sensor which detects a safety-control suspension region of the window and which is an accurate sensor. A spiral guide groove is formed in the inner surface of a housing opposite to a rotational plate which is rotated by an output shaft of a motor which opens/closes a window. A follower which is guided by the spiral guide groove is able to move along a straight guide groove provided for the rotational plate in the radial direction. Terminals in the form of conductive films are provided for a printed circuit board accommodated in the housing. When the rotational plate has been rotated, the follower is guided by the spiral guide groove so as to be moved in the straight guide groove. Thus, a slide member provided for the follower is brought into contact with the terminals so that the terminals are conducted with each other.

Abstract: A memory actuator is provided for a rearview mirror system having a reflective element and a controller. The memory actuator includes a housing and at least one positioning member extending from the housing to move the reflective element about at least one degree of freedom. At least one motor is provided for driving the positional member. A linear position transducer having a body is provided for coupling to the reflective element and a circuit board is positioned in the housing. The body of the linear position transducer is guided at the circuit board in at least one direction and moves alone the circuit board between a plurality of positions in response to movement of the reflective element about the at least one degree of freedom. The circuit board is configured to generate a signal to the controller as a function of the position of the body of the linear position transducer along the circuit board.

Abstract: The present invention is directed to a method and apparatus which utilizes a software-based digital signal processing circuit to generate a signal which is representative of the status of a movable component. A preferred embodiment of the apparatus of the present invention includes a synchro which is connected to a movable component. An analog reference excitation may be applied to the synchro, and the synchro generates analog synchro signals which bear a relationship to the status of the movable component. The analog synchro signals are converted to digital synchro signals by a plurality of analog-to-digital converters. A digital reference signal and the digital synchro signals are provided to a software-based digital signal processing circuit which preferably corrects constant and time-varying errors in the digital synchro signals and generates a status signal which is representative of the status of the movable component.

Abstract: In a moving apparatus of an arm for a tool edge sensor, the arm can be moved between a housing position which does not obstruct a processing work and a detecting position projected from the housing position. The apparatus is provided with a detecting sensor at a forward end of the arm, a moving device for moving the arm between the housing position and the detecting position, end a positioning device formed of at least six-point contacts arranged separately for three-dimensionally restricting the arm at the detecting position. When the arm is moved between the housing position and a position right before the detecting position, it is moved by the moving device, and at the detecting position of the arm, the arm is released from the moving device and positioned only by the positioning device. Since a positioning error due to the moving device at the time of positioning the detecting position does not occur, the arm can be positioned extremely accurately.

Abstract: An apparatus for moving a stage, supported by a base, to a target position. The apparatus includes a motor for driving the stage in X and Y directions, a laser interferometer for measuring a current position of the stage in the X and Y directions and a controller for generating a control signal for controlling the motor to move the stage to the target position in the X and Y directions on the basis of the target position and for dynamically setting a transfer function associated with generation of the control signal in correspondence with the current measured position. The controller sets the transfer function so that a gain decreases as the stage moves toward a peripheral portion of the base.

Abstract: The head/disk tester of the invention has a housing 43 that houses spindle 44 that rotatingly supports a magnetic disk 31. The housing supports a moveable carriage 30 that, in turn, supports a magnetic head 32. Positioning means 39 and 41 are used to move the carriage and the magnetic head across the magnetic disk. These positioning means include stepper motors that realize coarse positioning of the magnetic head, and a piezo actuator 37 that is used for fine positioning. Linear encoders 40 and 42 located at both sides of the carriage provide feedback information to a closed-loop positioning system that controls the piezo actuator. A set of special signals ("servo bursts") pre-written at a given track of the magnetic disk is used as an additional source of feedback information for the same closed-loop positioning system. This positioning system includes a servo analyzer 45 that reads and processes servo burst signals from the magnetic disk, and a position controller 49 that controls the piezo actuator.

Abstract: A movable body is moved towards an object for contact, it is determined whether a representative load for driving load such as a current instruction value for a servo amplifier providing controls for movement of the movable body has exceeded a reference value or not, and when the current instruction value exceeds the reference value, positional data for the body at this point of time is written in a memory, difference between the current instruction value and the reference value at this point of time and on is accumulated, and when the accumulated difference value reaches a specified value, a position indicated by the positional data in the memory is regarded as a contact position.

Abstract: An electromagnetic rotating machine driven by an electromagnetic action between a stator and a rotor has drive windings fitted to the stator for generating a rotating magnetic field for rotatably driving the rotor, position control windings fitted to the stator for generating a magnetic field having a different number of poles than that of the drive windings, a magnetic force generation circuit for generating a magnetic force to act on the rotor by supplying the position control windings with an electric current effective to unbalance the magnetic field on the stator side, a circuit for detecting an induced voltage or current generated in the one or more position control windings in response to radial displacement of the rotor and the rotating magnetic field generated by the drive windings, a circuit for detecting radial displacement of the rotor based on the induced voltage or current and the magnitude and speed of the rotating magnetic field, and a position control circuit for controlling the radial positio

Abstract: A method for calibrating the center point of a tool attached to a robot face plate or other machine uses a calibration block having vertical and horizontal faces. The position of the tool center point is determined by moving the tool from a starting position to touch one of the faces, recording the location of the face plate and returning the tool to the starting point. This is repeated for the other surfaces. Then the tool center point can be calculated from the recorded locations. Also disclosed is a calibration block having a centering area with four walls arranged to form a parallelogram and a leveling area with four walls arranged to form an x, y coordinate axis.