Abstract: A uniaxial drive unit is provided with a tiltable pulse generating device having a joystick, which generates a continuous pulse of a frequency corresponding to the tilt angle of the joystick, and a rotary encoder having a knob, which generates a pulse of a frequency corresponding to the turning speed of the knob and generates pulses of the number corresponding to the turning angle of the knob to drive a linear motor. High-speed and medium-speed operations are carried out by using the tiltable pulse generating device, and low-speed fine feed is carried out by using the rotary encoder.

Abstract: The invention provides a synchronous motor sensorless controller which drives a synchronous motor without use of a rotational position sensor. The controller has a relative position counter 4 which acquires an estimated position of a magnetic pole from the position-and-speed estimation device simultaneously with resetting a summated value to zero when the reference position signal is input and which starts summation operation; and a speed instruction generator 3 having a position controller 29 which performs position control operation on the basis of a deviation between an instruction value pertaining to the amount of movement from the reference position and a summated value output as a relative position from the relative position counter, the generator outputting a speed instruction. The sensorless controller can position at a predetermined location a synchronous motor not having a position sensor.

Abstract: A single-body structure is presented for use as a tool tip for making modifications and/or collecting measurements on a target object. The single-body structure comprises a first end portion, a second end portion opposite the first portion, and a mid portion between the first and second end portions, wherein a central axis can be defined extending from the first end portion to the second end portion, and wherein the single-body structure has a maximum linear dimension of approximately 50 microns or less. The single-body structure may be comprised of diamond. One of the first and second end portions may have a larger cross sectional area, in a plane perpendicular to the central axis, than does the other of the first and second end portions. One of the first and second end portions may have a larger cross sectional diameter, in at least one direction perpendicular to the central axis, than does the other of the first and second end portions.

Abstract: A high accuracy stage supported in six degrees of freedom by electromagnetic bearings. Movements in the horizontal plane of the stage are controlled by variable reluctance actuators which are mounted between the high accuracy stage and a coarse stage so as not to distort the high accuracy stage during movements thereof. The high accuracy stage is supported in three vertical degrees of freedom by electromagnetic actuators disposed between the coarse stage and the high accuracy stage and aided by a supplemental vertical support disposed adjacent to the actuators. Preferably, the high accuracy stage is suspended from a bar supported by the supplemental vertical support, which is preferably air bellows.

Abstract: The present invention is a control system for conditioning movement of a work implement during a work cycle. In one embodiment, the control system comprises an electronic-hydraulic valve connected to the work implement and a computer system having a central processing unit and a memory device. The control system further comprises a mode control module stored on the memory device. The mode control module is generally adapted to detect whether the control handle of the work implement is signaling for operating in a smooth mode or an abrupt mode, and to output a control signal to the electronic-hydraulic valve to control operation of the work implement during the smooth mode or the abrupt mode. The mode control module comprises a smooth mode module and an abrupt mode module. The smooth mode module and the abrupt mode module are adapted to optimize movement of the work cycle during the smooth mode, and abrupt mode, respectively.

Abstract: Method and apparatus for controlling a motor. A digital to analog converter (DAC) converts input digital values to corresponding analog voltages over a range of different selectable dynamic operating ranges. A first motor adjustment signal within a first dynamic range of the DAC is generated in relation to a velocity error of the motor, and applied to the DAC to control flow of current through the motor. The DAC is adjusted to a different, second dynamic range when the first motor adjustment signal is proximate an upper end or a lower end of the first dynamic range. Expanding the dynamic range allows greater amounts of current to be applied to the motor; contracting the dynamic range provides higher resolution (volts/count) and greater stability. The different ranges are automatically selected for different motor load conditions.

Abstract: Where high control precision is required in contour control or the like, mode B for a short PWM period is selected to assure a high control precision. Where high torque is required in fast feed, high acceleration or deceleration, mode A for long PWM period is selected so as to decrease the rate of the time of dead zone &dgr; where voltage is not applied to the motor.

Abstract: An actuator is configured to reliably provide fine and coarse positioning or adjusting for objects such as a telescope or other technical or scientific instrument or communication components, preferably at cryogenic as well as higher temperatures. The actuator includes a fine positioning system and a selectively engageable coarse positioning system. The fine positioning system includes a flexure structure constructed to provide support and strength, preferably in all axes, such as may be needed to withstand launch forces. Preferably flexure axes are defined at upper and lower edges of sidewalls and at intermediate positions of sidewalls. A cam or other suitable device adjusts distance between sidewall intermediate flexures and, by operation of sidewall flexures, adjusts the distance between upper and lower surfaces.

Abstract: The present invention preferably employs non-contact, small-displacement, capacitive sensors to determine Abbe errors due to the pitch, yaw, or roll of a near linear mechanical stage that are not indicated by an on-axis position indicator, such as a linear scale encoder or laser interferometer. The system is calibrated against a precise reference standard so the corrections depend only on sensing small changes in the sensor readings and not on absolute accuracy of the sensor readings. Although the present invention is preferred for use in split-axis positioning systems with inertially separated stages, the invention can be employed in typical split-axis or stacked stage systems to reduce their manufacturing costs.

Abstract: The present invention provides a position control apparatus in which a motor output torque can be approximated to that of the maximum output torque curve of the motor by generating a position command combining constant acceleration and exponential acceleration. This position control apparatus comprises means for generating a position command so as to give constant acceleration by adding an acceleration unit quantity &Dgr;Naa, set as a parameter beforehand, to a speed unit quantity N(n), means for generating a position command by calculating an acceleration unit quantity using an exponential function expression and by adding the calculated result to the speed unit quantity N(n), and means for generating a position command by comparing the present speed unit quantity N(n) and a function change speed unit quantity Nc set as a parameter beforehand and by selecting either of the command generating means described above on the basis of the compared result.

Abstract: A command trajectory drives a stage to produce a smooth motion while minimizing any vibrations or oscillations of the structure. The command trajectory provides an acceleration and a deceleration that have derivatives, known as the jerk, equal to zero at the beginning and end of the acceleration and deceleration periods. Because the jerk is equal to zero at the beginning and end of acceleration and deceleration, the influence of the reactive forces on the positioning system's structure is reduced, thereby minimizing oscillation of the structure. Moreover, the jerk is continuous throughout the acceleration and deceleration periods, resulting in a smooth continuous motion of the stage. The jerk on the stage during acceleration and deceleration has an adjustable duration to reduce the structural disturbances and decrease settling time.

Abstract: A circuit to establish an accurate instantaneous position of a DC motor rotor includes an input terminal to receive a rotor position signal. A first counter circuit counts to a value between two successive rotor position signals at a slow clock rate, and stores this count value in a register. Then a second counter begins counting from zero at a system clock rate, which is faster than the slow clock rate. The first counter circuit and the second counter circuit are evaluated by a comparator, and when the counters equal one another, the instantaneous position signal is generated. Alternately, the second counter can be a down-counter that is initially loaded with the count value, and the instantaneous position signal is generated when the second counter reaches zero.

Abstract: A stage assembly (10) for moving and positioning one or more objects (24) for an exposure apparatus (28) is provided herein. The stage assembly (10) includes a fine stage (14) and a coarse stage (18). The fine stage (14) includes a holder (15) that retains the object (24). The stage assembly (10) also includes a fine Y mover (32) and a fine X mover (34) that precisely move the fine stage (14) relative to the coarse stage (18). Uniquely, the fine movers (32), (34) are positioned on only one side of the holder (15). With this design, the resulting stage assembly (10) has a relatively low mass and a relatively high servo bandwidth. Further, with this design, the stage assembly (10) is readily accessible for service and a measurement system (16) can be easily positioned near the fine stage (14). The stage assembly (10) can also include an anti-gravity mechanism (40) that minimizes distortion of a stage base (12) that supports the fine stage (14) as the fine stage (14) moves above the stage base (12).

Abstract: A method of controlling the drive of computer-controlled transporting devices (2), in particular crane facilities with lifting winches and at least one mast supported on a moving frame on which are mounted shelf operator devices provided with load-carrying means and a lifting platform, and including a current control circuit (7), a drive control circuit with a speed control circuit (6), and a position control circuit (5), extend the possibilities of intervention when an instantaneous dynamic behavior of a transporting device (2) is calculated from an available data tree of a state and disruption monitor-regulator module (8) by using available measurement and setting values-containing information on a device dynamic and based on coefficient-characteristic fields, wherein the coefficient-characteristic fields incorporate structural details and/or dynamic characteristics of the transporting device and are determined by a regulator module (9) which performs an automatic self-teaching coefficient identification, p

Abstract: The present invention provides a high precision three-dimensional alignment system using SPM techniques and method of using the same. The system comprises a fine distance control unit for the effective three-dimensional micromovement in the nanometer range of a planar object, and proximity detection unit to monitor the alignment process. In the preferred embodiment, the fine distance control unit comprises a set of at least three strategically positioned fine distance control elements which are capable of controlled expansion and contraction in the nanometer range. The most preferred embodiment of the fine distance control element comprises a piezoelectric tube, which crystal size may be varied by varying an applied voltage. This system may be applied to microlithography, in which case the planar object is a scribing tool having a planar base with multiple tips fabricated on one surface.

Abstract: A video recorder capstan drive motor is controlled for slow-motion, freeze-frame and similar operations by setting a rate of acceleration or braking. A speed parameter is measured during an initial acceleration phase and is compared to a predetermined desired value. Based on the result of such comparison, current to the drive motor is limited, or an existing current limitation value is increased or reduced, so as to alter the acceleration or braking and bring the tape speed more nearly to the predetermined value. A representative current value can be stored in nonvolatile storage and used for such current limitation control, for so long as conditions remain unchanged. The value can be changed when conditions change, for example due to loading of a different tape cassette or a change in operational temperature.

Abstract: A slow-speed servomechanism includes a motor for driving a load; a direct drive transmission between the motor and the load; an incremental optical encoder connected to the load, the encoder having analog sine and cosine outputs; an analog to digital converter for converting the sine and cosine analog values to digital values; and a digital controller, connected to the motor and the analog to digital converter, for controlling the motor.

Abstract: An improved stop control system and method are provided for a motor having a drive mechanism in which the motor is coupled to a motor controller that controls the speed and position of the drive mechanism using a first signal indicative of a commanded position of the drive mechanism, a second signal indicative of the actual speed of the drive mechanism and a third signal indicative of the actual position of the drive mechanism. The improved system/method uses a first circuit that receives the first and third signal and generates an error signal indicative of a difference therebetween. A second circuit receives the error signal and compares same with a threshold position error. The result of this comparison is used to selectively supply the second signal (i.e., speed) to the motor controller at least whenever the error signal is less than the threshold position error so that the motor controller can use the second signal in conjunction with the third signal to stop the motor.

Abstract: A position control apparatus for synchronously controlling the movement of fine stages in a high-precision scanning positioning instrument. The position control apparatus uses actuators to adjust the fine stages with six degrees of freedom. By adjusting the fine stages, any synchronous errors between the fine stages during scanning may be dynamically corrected. Further, the fine stages may be adjusted during periods of acceleration and deceleration to reduce the settling time and consequently increasing throughput. Encoders directly attached to the actuators produce signals that are used in a velocity feedback loop. The locations of the fine stages are measured by interferometers. The position control apparatus uses a position control circuit to control the actuators to compensate for synchronous error.

Abstract: Torque ripples of a motor having interior permanent magnets can be reduced through the following method and the torque ripple controller using the same method: first, drive the motor having a plurality of phase windings and interior permanent magnets with a basic current supply circuit which outputs a basic current having a predetermined waveform, then store torque ripple waves produced in the running motor or obtained through a numerical analysis into a torque-ripple-wave-memory, next, compensate the torque ripple wave tapped off from the memory according to a prepared torque ripple compensation pattern and transform it to a torque compensation waveform with a torque-compensation-waveform-producing-circuit, further, multiply the torque compensation waveform tapped off from the waveform producing circuit by the basic current with a multiplier to output a torque ripple control current, and, supply the torque ripple control current to the plurality of phase windings shifting a phase by a predetermined electrica

Abstract: A scan-projection type exposure apparatus quickly suppresses disturbance in synchronization between a wafer stage and a reticle stage, and enables high-precision pattern exposure. This apparatus employs a master-slave control with a wafer-stage side as the master with a reticle-stage side as the slave, so as to correct a target value of a position control system of a rough-motion stage or that of a position control system of the reticle stage by using motion-mode errors e.sub.g, e.theta..sub.x and e.theta..sub.y in a one-to-one correspondence with a disturbance occurring to the rough-motion stage of the wafer stage due to movement of a fine-motion stage of the wafer stage.

Abstract: The present invention provides a position control unit having a torque command computing device (a position control circuit, and a speed control circuit) for outputting a torque command signal (q-axis current command signal Iq*) according to a positional command signal .theta.m* given from the outside and a positional detection signal .theta.m for an electric motor, and a torque control device (current control circuit) for controlling a torque of the electric motor according to a torque command signal outputted from the torque command computing device, in which the torque control device selects a gain Kqp or a gain Kqi according to whether an absolute value of a positional deviation between the positional command signal .theta.m* and the positional detection signal .theta.m is larger or smaller than a gain switching reference value P for a positional deviation.

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: A precision positioning control apparatus includes a coarse positioner, a fine positioner, a displacement totalizer for totaling the displacements of the two positioners, a total displacement detector for producing a total displacement signal, a comparator for producing an error signal, a coarse positioner adjuster for adjusting the error signal and inputting the adjusted signal to the coarse positioner, and fine positioner adjuster for adjusting the error signal and inputting the adjusted signal to the fine positioner. The coarse position adjuster includes a gain element, a transfer element, a limitter, an integrator, a gain adjuster and an adder.

Abstract: A multi-rate positioner system (50) receives unpanelized positioning commands from a database storage subsystem (64), profiles the commands (72) into a half-sine positioning signal, and further processes the signal into a low-frequency positioning signal (LFP) and a high-frequency positioning signal (HFP) for actuating respective slow (56, 58) and fast (54) positioners to target locations on a workpiece (62). The slow and fast positioners move without necessarily stopping in response to a stream of positioning command data while coordinating their individually moving positions to produce temporarily stationary tool positions (140) over target locations defined by the database. The multi-rate positioning system reduces the fast positioner movement range requirement while providing significantly increased tool processing throughput.

Abstract: A system for measuring the angle of rotation in order to determine the absolute angular position of the shaft of an electromotor is described which consists of a device for measuring the angle of rotation (10) and a control unit (11) connected to one another via an electric interface. The electric interface comprises an analog process data channel (8) and a digital parameter channel (9). The control unit (11) controls a change-over switch (7) of the process data channel (8) via the digital parameter channel (9). As a result thereof, a sine-cosine signal pair with one period for revolution is supplied via the process data channel (8) to the control unit (11) in order to determine the absolute angular position for the starting of the motor. Then, a sine-cosine signal pair with a high number of periods per revolution is supplied via the process data channel (8) in order to incrementally count the angle of rotation.

Abstract: A signal processing apparatus is provided for processing first and second periodic analog signals having the same period and having a fixed phase relationship therebetween. The apparatus includes an A/D converter for converting respective amplitudes of the first and second periodic analog signals into first and second digital signals. The apparatus also includes a phase digitizer for generating a signal from the first periodic analog signal, the generated signal having a period that is shorter than the period of the first periodic analog signal, and a high speed signal processing portion for generating from the generated signal a periodicity and first phase information of the first periodic analog signal. The apparatus further includes a another signal processor for producing second phase information of the first periodic analog signal from the first and second digital signals, and for correcting the periodicity on the basis of the first phase information and the second phase information.

Abstract: A controlled variable is detected at each predetermined timing by a detecting section 2, and the controlled variable is compared with a target value by a comparator 3 to obtain a deviation. A manipulated variable is calculated, based on the deviation, by a compensating section 4, and a height H corresponding to the manipulated variable is calculated by a controlling section 5. A manipulated pulse having the height H and a predetermined width W is provided to a controlled system 6 by the controlling section 5.

Abstract: An emergency robot shutdown circuit reliably stops a movable component of a robot which has suffered an overtravel condition. The emergency robot shutdown circuit has three relays, and detects an overtravel condition of the robot with a dog located in a limit position of a normal operation range of the movable component of the robot to command an emergency shutdown of the robot. The second relay holds an overtravel signal which is outputted from a detecting circuit. A switching transistor is connected parallel to a make contact of the second relay, and an overtravel cancel switch is connected parallel to another make contact of the second relay. The base of the switching transistor is supplied with an overtravel unlatching pulse in synchronism with the closing of the overtravel cancel switch. The third relay, which is connected in series with the other make contact of the second relay, has three make contacts which make up a power cutoff circuit.

Abstract: An encoder for indicating a position of a movable member and for generating at least two signals which are offset in phase from one another in accordance with movement of the movable member. The encoder includes a position detector and a presettable counter. The position detector generates a position reference signal indicating at least one reference position during movement of the movable member, and the presettable counter is preset for an absolute position of the encoder during movement of the movable member when the position reference signal is generated. The encoder can be constructed in a small size enabling use in servo systems and in industrial robots.

Abstract: An actuator for heating, cooling and climatic valves in vehicles includes a gear housing, an electric motor placed therein, a reduction gear acted on by the turning moment of the electric motor, a drive shaft and a position determining device connected thereto. A slide carrier with teeth on its perimeter allows use of an adjusting tool to make adjustments to the position determining device. Other fixing areas are provided on the slide carrier and in the driven gear which make it possible to form lock the slide carrier to the driven gear by means of a rapidly hardening substance without damaging the gear.

Abstract: A stage driving system capable of positioning an object with a higher speed and a higher precision than prior systems. The system includes a base member, plural movable members provided on the base member, and a controller for controlling the plural movable members so as to substantially suppress the vibration of the base member caused by the displacements of the plural movable members.

Abstract: A method and apparatus for synchronizing the operation of multiple elements of a system to the motion of a movable element using a programmable element as the control element.

Abstract: The invention relates to a recording apparatus for effecting recording on a recording material. The recording apparatus comprises a stepping motor, a recording head capable of reciprocating along the recorded material by a drive force of the stepping motor to effect recording on the recording material, an angular position detector for detecting a rotated angular position of a rotor of the stepping motor, a controller for controlling drive of the stepping motor in a closed-loop manner dependent on the detected result of the detector, a controller for operating the stepping motor in a mode of stepwise motor drive, a movement position detector for detecting a movement position of the recording head, and switching circuitry for switching over between the closed-loop control and the stepwise motor drive dependent on the detected value of the movement position detector.

Abstract: A magnetic bearing is provided which may be utilized in a fine position control or movement system. Stability is enhanced by providing separate mechanisms for supporting the weight of a platen or other object being controlled with electromagnets utilized to control or compensate for motion of the platen in N degrees of freedom. The support mechanism is preferably one or more permanent magnets having an air gap with the platen which is greater than the air gap for the electromagnets. The mechanisms for supporting the weight of the platen may be made adjustable so as to support the weight of the platen regardless of any changes in such weight by, for example, adjusting the air gap for the permanent magnet to compensate for weight changes. Resonant vibration is reduced by constructing the platen of a hollowed, cellular structure, for example, a honeycomb structure.

Abstract: A positioning control method and apparatus in which a fine movement mechanism is moved without exceeding a movable area so that positioning of a large amount of displacement can be attained with high accuracy and high-speed positioning from a point to a point with the same control method. A coarse movement mechanism (101) has a large amount of movement and low positioning accuracy and a fine movement mechanism (102) on the coarse movement mechanism has a small amount of movement and high positioning accuracy.

Abstract: Disclosed is herein a rotational position detector for a robot which can always accurately detect the rotational positions of each rotational member based on the output values from each absolute value detector regardless of the rotational conditions of the rotational member. Each absolute value detector (resolver) is connected to each rotational member such that the ratio of the rotational angle period of the absolute value detector to the rotational angle period of the rotational member is set to be 1:N (N is an integer larger than 1).

Abstract: A servo circuit having a speed detection circuit for detecting a real speed from a position signal from an object under servo control. A speed error detection circuit generates an error between a target speed and the real speed. A position error detection circuit generates a position error signal from the position signal. A switching unit switches connection of the servo object to the speed error detection circuit and the position error detection circuit. A main processing unit controls the switching of the switching unit. Near the target position, speed control by the speed error detection circuit is switched to position control by the position error detection circuit. A speed detection gain adjustment unit is provided in the speed detection circuit. The main processing unit measures the intervals between the position signals and, based on the measured value, changes the detection gain of the speed detection gain adjustment unit.

Abstract: Method and apparatus for control of positioning of a recording/playback head or other controlled object. When a controlled object reaches the vicinity of a target position, the control system is switched from operation as a velocity control system to operation as a position control system. By using state variables of the controlled object at that time, coefficients corresponding to the detected state variables are determined from characteristics of the controlled object which are determined in advance. By using the determined coefficient values, initial values upon start of position control of the position control system are set, and positioning control is then carried out.

Abstract: A positioning system moves a movable element along a path and detects the movable element in a plurality of predetermined positions spaced along the path. The movable element is positioned selectively in the positions using a signal indicative of the detected movable element in the positions and a positioning command.

Abstract: A magnetic bearing is provided which may be utilized in a fine position control or movement system. Stability is enhanced by providing separate mechanisms for supporting the weight of a platen or other object being controlled with electromagnets utilized to control or compensate for motion of the platen in N degrees of freedom. The support mechanism is preferably one or more permanent magnets having an air gap with the platen which is greater than the air gap for the electromagnets. The mechanisms for supporting the weight of the platen may be made adjustable so as to support the weight of the platen regardless of any changes in such weight by, for example, adjusting the air gap for the permanent magnet to compensate for weight changes. Resonant vibration is reduced by constructing the platen of a hollowed, cellular structure, for example, a honeycomb structure.

Abstract: An optical system adjusting device for a camera comprises a first driver for driving the optical system of the camera; a second driver for driving the optical system at a finer pitch than the first driver; and a control system arranged to divide a degree to which the optical system is to be driven into a first degree to which the optical system is to be driven by the first driver and a second degree to which the optical system is to be driven by the second driver and to cause the first driver to drive the optical system to the first degree and the second driver to drive the optical system to the second degree.

Abstract: A technique for overcoming the difficulties that arise from the transition between coarse and fine loop control. Coarse and fine phase locked loops, each having a respective latch provide a coarse number in the range 000.0.degree.-359.9.degree. and a fine number in the range of 0.0000.degree.-0.9999.degree.. The coarse number is offset relative to the fine number so that the least significant digit (tenths digit) of the coarse number is always less than the most significant digit (tenths digit) of the fine number over the entire range of motion. The fine number latch is clocked by a reference clock (ZDS) while correlation circuitry provides a clock signal for the coarse number latch. The correlation circuitry generates the clock signal when the tenths digit of the coarse number agrees with the latched fine number. The result is a latched fine number and a coarse number that is latched when it correlates with the fine number (tenths digits agree).

Abstract: A system for carrying out reference point return in a numerical control device is provided, including a deceleration dog having a short length and arranged at a machine table, a deceleration limit switch operated by the deceleration dog, for generating a deceleration start signal, and a time setting device (6) for setting a deceleration time, starting with a generation of the deceleration start signal and ending with a generation of a deceleration end signal, and a slow-speed travel time. A reference point return processing device (5) starts a deceleration of the machine table in response to the deceleration start signal, and stops the machine table at a first electrical grid point reached by the machine table after the slow-speed travel time has elapsed after the passing of the deceleration time.

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

Abstract: As disclosed herein, a new and improved method and apparatus provide for fine tuning the position of a servomotor used to drive a transducer mounted on an ultrasound probe to a desired position. This improvement is accomplished by processing the analog quadrature output signals of an incremental optical encoder, coupled to the servomotor. The improvement uses the positional information derived from the analog quadrature output signals. The analog quadrature output signals, defined as sine and cosine, are converted to digital square waves. The digital square waves are decoded to produce digital position quadrants, wherein each quadrant represents a specific motor position. The corresponding digital square waves are also decoded by a logic array device and coupled to the select input of an analog switch.

Abstract: In an apparatus for measuring texture and characterization of the surface of a sample on the basis of the drive signal of a servo control circuit by allowing a probe-tip (1) to approach the sample (2) and subjecting the probe-tip (1) to servo control so that a current, which is generated by moving the probe-tip (1) on the sample surface and which flows between the probe-tip (1) and the sample (2), becomes constant, the present invention discloses a surface metrological apparatus comprising a circuit (11, 12) for correcting the texture and characterization of the sample by use of a current error of the measured value of the current described above from the set current value.

Abstract: A motor feedback control system which in addition to a quantized digital position feedback value, uses a feedback signal which represents the error between the actual motor position and the quantized digital position. The error function is combined with the quantized digital position value to produce a digital position value with greater resolution. The combined value is differentiated to produce a velocity value for velocity feedback control of the motor.

Abstract: A technique for overcoming the difficulties that arise from the transition between coarse and fine loop control. Coarse and fine phase locked loops, each having a respective latch, provide a coarse number in the range 000.0.degree.-359.9.degree. and a fine number in the range of 0.0000.degree.-0.9999.degree.. The coarse number is offset relative to the fine number so that the least significant digit (tenths digit) of the coarse number is always less than the most significant digit (tenths digit) of the fine number over the entire range of motion. The fine number latch is clocked by a reference clock (ZDS) while correlation circuitry provides a clock signal for the coarse number latch. The correlation circuitry generates the clock signal when the tenths digit of the coarse number agrees with the latched fine number. The result is a latched fine number and a coarse number that is latched when it correlates with the fine number (tenths digits agree).

Abstract: A method of and apparatus for controlling the velocity of an industrial robot where the velocity is controlled without producing an edge when an instruction velocity is higher than an allowable velocity and an operator can readily recognize the actual velocity of the robot. The method includes the setting of an allowable velocity for a first step section or each of step sections in an acceleration or deceleration section between taught points for each of the axes of the robot. At the first or each step section an instruction velocity to each axis is compared with a corresponding allowable velocity, and when the former is highter than the latter, a control cycle after which a next trigger signal is to be developed is modified using the allowable and instruction velocities.