Canon Kabushiki Kaisha

Naoki Kawamata

Makoto Takamiya

Hidejiro Kadowaki

Jun Ashiwa

Kou Ishizuka

Hiroyuki Hagiwara

Hiroyuki Shiomi

Hiroshi Itoh

Masayoshi Sekine

Isao Harigaya

Hiroyuki Kimura

Shigeki Kato

Toshiaki Kondo

Hiroaki Takeishi

Jun Tokumitsu

Masahiro Morisada

Yasuhiko Ishida

Yoichi Kubota

Katsuhiro Fujii

A controller which generates a driving instruction to control driving of an object while detecting a position of the object based on two periodic signals that are provided by an encoder and have different phases, comprises a counter configured to count periods of one of the two periodic signals, and a processor configured to detect the position of the object based on an arctangent value of a ratio of values of the two periodic signals and a count value provided by the counter, and to generate the driving instruction based on the position, wherein the processor is configured to compensates an error in the count value based on the driving instruction generated in the past and an acceleration of the object computed based on the arctangent value and the count value, and to compute the position of the object based on the compensated count value.

Controller and machining apparatus with position encoder compensation

A rotation-angle detecting apparatus detects a rotation angle of a rotating disc having radial markings, includes a plurality of detectors arranged at opposite sides of the axis of rotation of the disc and facing the markings, each of the detectors operable to detect a light beam from the markings, and outputting a pair of periodic signals having a 90-degree phase difference between the members of the pair; an analog-to-digital converter arranged to convert pairs of periodic signals from the detectors into pairs of digital signals; a digital signal processor configured to process the pairs of digital signals from the analog-to-digital converter; a binarization unit arranged to binarize the pairs of periodic signals from the detectors; and a counter arranged to count the pairs of periodic signals binarized by the binarization unit. The digital signal processor determines the rotation angle of the disc based on the pairs of digital signals from the analog-to-digital converter and count results from the counter.

Rotation-angle detecting apparatus

An apparatus for optically detecting rotational position information of a rotating object, includes a light source, a detector which is located at a position to receive scattered light from the rotating object when the rotating object is irradiated with a light beam from the light source, and outputs a frequency signal based on the scattered light, a signal processing system for detecting rotational position information by performing signal processing for the frequency signal from the detector, and a rotation control system for controlling rotation of the rotating object. The rotation control system preliminarily rotates the rotating object in detecting the rotational position information.

Optical rotational position information detecting apparatus

This invention is to allow accurate high-speed coincidence detection while preventing any increase in circuit scale. To achieve this object, a coincidence detection apparatus includes a detector which outputs at least two periodical signals in accordance with the displacement of an object, a digital interpolator which processes the periodical signal output from the detector at a predetermined time interval to generate a displacement or angle at a period shorter than the period of the periodical signal, a pulse generation unit which generates a constant frequency pulse signal, a counter which counts the pulse signal output from the pulse generation unit, and a pulse conversion unit which calculates a value to be set in the counter from the difference between displacement information corresponding to the target position of the object and the output from the digital interpolator.

Coincidence detection apparatus and method

An apparatus having a first system for forming a composite light beam of two light beams to be made to interfere with each other, a splitting member for amplitude-splitting the composite light beam into three or more split light beams in the same area, and a second system for obtaining interference light beams of different phases from the plurality of split light beams. Also, an apparatus for effecting information recording on a hard disc drive device comprising an (i) optical system for splitting a light beam into two light beams, causing one of the two light beams to be condensed and reflected by the side of an arm for a recording reading head in the hard disc drive device, and superposing the condensed and reflected light beam on the other light beam to thereby obtain a composite light beam, (ii) a splitting member for amplitude-splitting the composite light beam into three or more split light beams in the same area, (iii) an optical member for obtaining interference light beams of different phases from the plurality of split light beams, (iv) light receiving elements for detecting respective ones of the interference light beams of different phases, (v) a control system for effecting the positioning of the arm on the basis of the result of the detection by each of the light receiving elements, and (vi) a signal writing-in system for writing a signal into a hard disc through the recording reading head each time the arm is positioned.

Interference device, position detecting device, positioning device and information recording apparatus using the same

An angular division apparatus for circumferentially dividing a rotating object into a plurality of areas by using Doppler pulses includes an optical head for applying a beam emitted from a light source unit to a rotating object and detecting Doppler pulses based on a shift of the frequency of the light scattered from the rotating object, and a counting unit for counting the Doppler pulses output from the optical head to determine the number of pulses for one revolution of the rotating object. The number of Doppler pulses for one revolution is divided by a division number for dividing the rotating object into a plurality of areas in the angular direction. The rotating object is divided into a plurality of areas in the angular direction thereof by using the number of Doppler pulses per divided area.

Apparatus for detecting rotational displacement information of a

A one-phase electromagnetic motor drive controller includes a one-phase electromagnetic motor, a position detection mechanism for detecting a rotational position of the motor and a control mechanism for controlling the drive of the one-phase electromagnetic motor from the detected rotational position. When the torque constant of the motor is used as a parameter of a control calculation, the torque constant parameter is corrected by the relationship between it and the rotational position of the electromagnetic motor.

Motor drive controller

An apparatus records information on a hard disk with a magnetic head arm provided in a hard disk drive. The apparatus comprises an interference measuring system, containing an outgoing portion for a measuring light beam to the arm and a reference light forming portion, for obtaining relative displacement information with respect to the arm by interfering the reference light with reflected light of the measuring light from the arm or a slider belonging to the arm, the interference measuring system having a light beam deflecting member for deflecting the measuring light and thus guiding the measuring light to a lateral surface of the arm or of the slider, a control system for generating a signal for positioning the arm with respect to the hard disk on the basis of the relative displacement information obtained by the interference measuring system, and a signal system for transmitting a signal for recording information on the hard disk to the magnetic head.

Information recording apparatus

This invention relates to a method of and an apparatus for detecting the amount of displacement of an object by the use of two periodic signals having a predetermined phase difference therebetween which are outputted in conformity with the displacement of the object. The apparatus has means for detecting the two periodic signals, means for calculating the ratio between the two periodic signals, and means for obtaining the amount of displacement of the object from the value of the ratio by reference to prestored data.

Method of and apparatus for detecting an amount of displacement

An image pick-up apparatus includes a detection circuit for detecting vibration of the apparatus body, a correction system for correcting the vibration by shifting an image, and a control circuit for controlling driving of the correction system in accordance with an output of the detection circuit. A closed loop frequency characteristic is constituted as a notch filter, and a blocking frequency of the notch filter is made variable on the basis of changes in the detected vibration frequency.

Image pick-up apparatus having vibration correcting circuitry

A positioning device and method includes a motor having a rotation axis, a driver for driving the motor on the basis of control information, a detector for detecting position information of the rotation axis of the motor, and a digital signal processor for performing an operation on the control information in accordance with the position information detected by the detector.

Device and method comprising a motor and/or a digital signal processor,

A tape transport system control device for controlling a tape transport system in which a tape payed out from a supply-side reel driven by a supply-side reel motor travels through a predetermined path to be taken up on a takeup-side reel driven by a takeup-side reel motor, includes a tape speed control servoloop for the takeup-side reel motor, a tape tension control servoloop for the supply-side reel motor, a detecting part arranged to detect a difference between a tape tension obtained on the side of the supply-side reel and a tape tension obtained on the side of the takeup-side reel, and a loop arranged to feed the detected difference of tension forward to the supply-side reel motor.

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Utsunomiya, Japan

Naoki Kawamata