KR101841821B1 - An absolute position measuring equipment using two absolute encoders and measurement method it using the same - Google Patents

An absolute position measuring equipment using two absolute encoders and measurement method it using the same Download PDF

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KR101841821B1
KR101841821B1 KR1020160001529A KR20160001529A KR101841821B1 KR 101841821 B1 KR101841821 B1 KR 101841821B1 KR 1020160001529 A KR1020160001529 A KR 1020160001529A KR 20160001529 A KR20160001529 A KR 20160001529A KR 101841821 B1 KR101841821 B1 KR 101841821B1
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encoder
value
gear
absolute position
wide
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KR20170082298A (en
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김병기
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김병기
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H1/00—Toothed gearings for conveying rotary motion
    • F16H1/02—Toothed gearings for conveying rotary motion without gears having orbital motion
    • F16H1/20—Toothed gearings for conveying rotary motion without gears having orbital motion involving more than two intermeshing members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H1/00—Toothed gearings for conveying rotary motion
    • F16H1/28—Toothed gearings for conveying rotary motion with gears having orbital motion
    • F16H1/34—Toothed gearings for conveying rotary motion with gears having orbital motion involving gears essentially having intermeshing elements other than involute or cycloidal teeth
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
    • G01B21/02—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness
    • G01B21/04—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness by measuring coordinates of points
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
    • G01B21/02—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness
    • G01B21/04—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness by measuring coordinates of points
    • G01B21/045—Correction of measurements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B5/00—Measuring arrangements characterised by the use of mechanical techniques
    • G01B5/004—Measuring arrangements characterised by the use of mechanical techniques for measuring coordinates of points
    • G01B5/008—Measuring arrangements characterised by the use of mechanical techniques for measuring coordinates of points using coordinate measuring machines
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D18/00—Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/347—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells using displacement encoding scales
    • G01D5/34707—Scales; Discs, e.g. fixation, fabrication, compensation

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)

Abstract

In the present invention, two absolute encoders are combined with an appropriate decelerating device to accurately measure an absolute position with respect to a long distance in order to measure the amount of physical displacement, and two moving devices To an absolute position measuring apparatus and a measuring method using an absolute encoder.
The absolute position measuring apparatus using two absolute encoders according to the present invention is coupled to a rotating shaft 104 that rotates in accordance with the movement of the measurement object, and measures a value corresponding to the rotation angle of the rotating shaft 104, A precision encoder 112 which is an absolute encoder for measurement; A reduction gear 106 meshing with a gear 105 formed on the rotation shaft 104 to reduce a rotation speed of the rotation shaft 104; A wide-angle encoder 113 for measuring a rotation angle corresponding to a rotation angle decelerated by the reduction gear 106 and outputting an absolute encoder for wide-area measurement; And an absolute position measuring controller 200 for analyzing measured values of the precise encoder 112 and the wide-angle encoder 113 and calculating an absolute position value according to the movement of the measurement object, It is provided for precise measurement.

Description

Field of the Invention The present invention relates to an absolute position measuring apparatus and an absolute position measuring apparatus using two absolute encoders,

More particularly, the present invention relates to an absolute position measuring apparatus and a measuring method, and more particularly, to an absolute position measuring apparatus and a measuring method, more specifically, to detect an absolute position of a long distance by combining two absolute encoders with a proper decelerating device, To an absolute position measuring apparatus and a measuring method using two absolute encoders which can measure a moving amount of a moving apparatus even when it is blocked.

Generally, a method of measuring a physical linear displacement includes a method using a linear potentiometer that measures a resistance value or a change in voltage when the wiper coupled to a measurement object moves while contacting the linear resistor, and a method of measuring a linear displacement of the measurement object A rotary encoder for converting a linear movement amount into a rotation angle and outputting a pulse proportional to the rotation angle, and a method using an ultrasonic distance meter or a laser distance meter have been widely used.

The linear potentiometer has a problem that the wiper is moved in contact with the resistor at all times, and the resistance is worn down when the resistor is used for a long period of time. The resistance of the resistor can not be made long, drift error occurs with temperature, There is a problem that a straight-line error due to digital conversion occurs.

The ultrasonic distance meter and the laser distance meter measure an elapsed time reflected by an object to be measured after outputting an ultrasonic wave and a laser and multiply the distance by a speed of a sound wave or a laser to calculate a distance, . However, in case of a sound wave, since the propagation speed varies with temperature, it is necessary to compensate for a temperature-dependent speed due to an error, and in the case of a laser, the speed of the laser light is too fast to cause an error in measuring the elapsed time .

The measurement method using the rotary encoder includes a method using an incremental encoder and a method using an absolute encoder. Among them, a method using an incremental encoder is a method in which a pulley is attached to an axis of an encoder, and a wire is wound around the pulley to detect a linear displacement at a rotation angle. Performance depends on the diameter of the pulley and the resolution of the encoder. There is no change in precision even when the length is long, and since the encoder output value is digital, there is no influence on the temperature change and stable measurement can be performed. The method using this incremental encoder detects the displacement by integrating the number of pulses generated in the incremental encoder by the controller and multiplying the total number of pulses by the mechanical constant. If the controller is powered off or the cable connecting the controller and the encoder When the device is moved in the cut state, the number of pulses output during the operation is lost and the position of the device can not be accurately measured.

Absolute encoders among rotary encoders are sensors that can measure the absolute position within one rotation. When the controller is turned off within one revolution, the position of the device can be read out as soon as the power is turned on There is an advantage. However, in the conventional method, when a long moving distance is measured due to a method using only one absolute encoder, a complex speed reduction gear is provided at the front end of the encoder to reduce speed, so that the entire movement amount should be compressed within one revolution of the absolute encoder. However, when the reduction gear is used, a large error occurs due to the backlash of the gear, and the precision of the rotary encoder, which is obtained by dividing the total travel distance by the resolution of the encoder, becomes relatively long as the travel distance is long.

Korean Registered Patent No. 10-1509578 (Registered on April 21, 2015)

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to precisely detect an absolute position of a long distance by combining two absolute encoders with a decelerating device composed of a plurality of gears And an absolute position measuring device and a measuring method using two absolute encoders which can measure a movement amount of a device as soon as the power is applied even when the device moves in a state where the power source is shut off.

According to another aspect of the present invention, there is provided an apparatus for measuring an absolute position of an object to be measured using an absolute encoder, the apparatus comprising: A precision encoder which is an absolute encoder for precision measurement for measuring and outputting a value according to an angle; A reduction gear engaged with a gear formed on the rotary shaft to reduce a rotation speed of the rotary shaft; A wide-angle encoder which is an absolute encoder for wide-area measurement for measuring and outputting a value corresponding to a rotation angle decelerated by the reduction gear; And an absolute position measurement controller for analyzing measured values of the precision encoder and the wide-angle encoder and calculating an absolute position value according to the movement of the measurement object. Here, the wide-area encoder can be replaced with a potentiometer.

The speed reducer includes a first gear that meshes with a rotary shaft of the rotary shaft and decelerates the rotational speed of the rotary shaft, a second gear that meshes with the first gear to reduce the rotational speed of the first gear, And a third gear that decelerates the rotational speed. A wide-angle encoder is installed on an axis of the gear installed at the last end of the plurality of gears to measure a value according to the reduced rotation angle. Here, the speed reducer may be a reducer or a harmonic driver integrally formed.

In addition, the axis of the gear on which the wide-angle encoder is installed is provided with an opaque detection disc having a detection groove for detecting a zero point, and a detection disc rotating together with the rotation of the gear shaft, A photoelectric sensor for detecting the zero point position is provided.

Wherein the detection disc is detachably coupled to the gear shaft via a fixing screw, a gear for adjusting the zero point is formed in the circumference of the detection disc, a gear formed on the circumference of the detection disc is coupled to the adjustment gear, The position of the detection disc is adjusted by rotating the adjustment gear in a state where the gear shaft and the detection disc are released from the fixed state, and then the gear shaft and the detection disc are fixed via the fixing screw, So that it can be changed.

Further, the adjustment bearing is fixed to the upper portion of the sensor fixing plate, and the adjusting bearing is closely attached to the spindle of the micrometer head fixed to the fixed block installed on the body of the absolute position measuring device, The sensor fixing plate provided with the adjustment bearing and the photoelectric sensor provided on the sensor fixing plate rotate to the left or right so that the detection position of the detection groove formed on the detection disc can be finely adjusted .

On the other hand, the absolute position measuring controller calculates the number of revolutions of the precise encoder using the value of the wide-angle encoder, multiplies the calculated number of revolutions of the precise encoder by the resolution of the precise encoder, The absolute value of the position of the object is calculated.

Here, the absolute position measurement controller checks the precision encoder rotation number calculation table in which the step-up lower limit value, the step-up upper limit value and the down step-band value are set for each revolution number of the precision encoder, A table index value in a range that is greater than or equal to the step-up lower limit value of the precision encoder rotation speed calculation table and smaller than the step-up upper limit value is set as the rotation speed of the precision encoder, If the value of the encoder is larger than the lower step limit value, down-step correction is performed to subtract 1 from the set number of revolutions of the precision encoder to calculate the number of revolutions of the precise encoder.

The step-up lower limit value, the step up upper limit value, the down step band value, and the down step lower limit value of the precision encoder rotation speed calculation table are set through the following equations.

[Mathematical Expression]

Figure 112016001277682-pat00001

Figure 112016001277682-pat00002

Figure 112016001277682-pat00003

Figure 112016001277682-pat00004

(Where A3 is the value of the wide encoder per rotation of the precision encoder, A3 = int (B1 / B2 + 0.5) where B1 is the value of the wide encoder in the entire stroke, B2 is the number of revolutions of the precision encoder with respect to B1, Α is a constant in the range of 0 to 0.499, β is a constant in the range of 0.5 to 0.999, γ is a constant in the range of 0 to 0.499, and δ is in the range of 0 to 0.75. Lt; / RTI >

The absolute position measuring controller includes a precise encoder interface unit to which a measurement signal is inputted from a precise encoder, a wide-range encoder interface unit to which a measurement signal is inputted from the wide-angle encoder, and a precise encoder measurement signal And a zero point signal input unit for receiving a zero point setting signal from an external zero point switch and transmitting the zero point setting signal to the microprocessor. And a position value output unit for outputting an absolute position value calculated through the microprocessor.

The absolute position measuring controller is provided with a zero point permission signal input section for receiving a zero point change permission signal from an external zero point permission switch and transmitting the zero point change permission signal to the microprocessor so that the zero point setting can be performed only when the zero point permission signal is ON .

In addition, the microprocessor receives parameter information from an external device through an LCD & Key board, a USB port or an RS-485 communication unit. The parameter information includes a Para_Unit for setting an operation unit in mm or cm, Para_Offset for setting a value to add or subtract a value, Para_Baud for setting a communication speed, Para_Ratio for setting a ratio of an absolute position value to an actual physical quantity of 1000 mm, and a signal when the absolute position value is reached or exceeded The output includes Para_Pos1 and Para_Pos2.

The microprocessor transmits the calculated absolute position value to an external device using at least one of an RS-232C communication unit, an RS-485 communication unit, an optical signal transmission / reception unit, an Ethernet communication unit, and a wireless transmission / reception unit.

According to another aspect of the present invention, there is provided a method for measuring an absolute position of an object to be measured using an absolute encoder, the method comprising: Measuring a value corresponding to a rotation angle of the rotation shaft in a precision encoder which is an absolute type encoder and inputting the measured value to an absolute position measurement controller; Measuring a value corresponding to a rotation angle decelerated by the reduction gear in a wide-angle encoder which is an absolute encoder for wide-range measurement installed in a reduction gear that reduces the rotation speed of the rotation shaft, and inputting the measured value to an absolute position measurement controller; The rotation speed of the precision encoder is calculated using the value of the wide-angle encoder measured by the absolute position measurement controller, the resolution of the precision encoder is multiplied by the resolution of the precision encoder, The absolute value of the position of the object is calculated.

Here, the absolute position measurement controller checks the precision encoder rotation number calculation table in which the step-up lower limit value, the step-up upper limit value and the down step-band value are set for each revolution number of the precision encoder, A table index value in a range that is greater than or equal to the step-up lower limit value of the precision encoder rotation speed calculation table and smaller than the step-up upper limit value is set as the rotation speed of the precision encoder, If the value of the encoder is larger than the lower step limit value, down-step correction is performed to subtract 1 from the set number of revolutions of the precision encoder to calculate the number of revolutions of the precise encoder.

The absolute position measuring apparatus according to the present invention can precisely measure an absolute position with respect to a long distance through an absolute encoder for precision directly connected to a rotary shaft and a wide-area absolute encoder installed in a decelerator connected to a rotary shaft, There is an effect that can be utilized in various fields such as elevator position control, dam control of a dam, crane control for loading and unloading containers, and the like, which require precise measurement for distance movement.

Further, in the present invention, by using two absolute encoders, even when the measurement object moves in a state where the power is off, the absolute position of the measurement object can be calculated using the output values of the two absolute encoders immediately after power is applied It is effective.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a portion of an absolute position measuring apparatus according to the present invention,
FIG. 2 is a side partial sectional view for controlling the fine zero point of the absolute position measuring apparatus according to the present invention,
3 is a diagram showing a relationship between output values of the precision encoder and the wide-angle encoder according to the present invention,
4 shows an example of a general backlash formed between two gears,
FIG. 5 is a conceptual diagram for measuring the number of revolutions of a precise encoder using a wide-angle encoder value according to a conventional method,
6 is a conceptual diagram for measuring the number of revolutions of a precision encoder using a wide-range encoder value according to the present invention,
7 to 9 show an example of a simulation result of continuous movement of the precision encoder and the wide-angle encoder according to the present invention in an Excel program,
10 is a conceptual diagram of a precision encoder rotation number calculation table according to the present invention,
11 is a block diagram of an absolute position measuring controller according to the present invention,
12 is a flowchart illustrating a process of measuring absolute position values through an absolute position measuring apparatus according to the present invention.
13 shows an example of the configuration of parameters used in the absolute position measuring apparatus according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a plan view of a portion of an absolute position measuring apparatus according to an embodiment of the present invention.

1, the absolute position measuring apparatus 100 according to the present invention includes a rotating shaft 104 that rotates in accordance with movement of an object to be measured, a rotating shaft 104 coupled to the rotating shaft 104, A deceleration gear 106 for decelerating the rotation speed of the rotation shaft 104 by engaging with a gear 105 formed on the rotation shaft 104. The precision encoder 112 is an absolute encoder for precision measurement, And a wide-angle encoder 113 for outputting a unique code value corresponding to a rotation angle decelerated by the reduction gear 106. The wide-angle encoder 113 and the wide- And an absolute position measuring controller 200 (shown in FIG. 12) for analyzing the measured values and calculating an absolute position value according to the movement of the measurement object.

The rotation shaft 104 receives rotational motion or linear motion of the measurement object in a rotational motion. A bearing 103 is inserted into the rotation shaft 104 to enable smooth rotation.

The precision encoder 112 coupled to the rotation shaft 104 is an absolute type encoder that outputs a unique code value for an arbitrary rotation angle within one rotation of the rotation shaft 104. The precision encoder 112, And outputs an eigenvalue corresponding to the rotation of the rotary shaft 104 according to the resolution, thereby accurately measuring the amount of movement of the rotary shaft 104 within one rotation.

A gear 105 is formed on the rotary shaft 104 and a reduction gear 106 for reducing the rotation speed of the rotary shaft 104 is coupled to the gear 105. In the embodiment of the present invention, And a plurality of gears that are sequentially coupled to the rotary shaft 104 and sequentially decelerate the rotary speed of the rotary shaft 104. That is, in the embodiment of the present invention, the reduction gear 106 includes a first gear 107a, a second gear 107b, and a third gear 107c having appropriate deceleration ratios, The number of reduction gears 106 and the gear ratio can be appropriately changed according to the movement range of the detection subject and a speed reducer or a harmonic driver or the like constituted by a single component can be used by another deceleration method It is possible.

A wide-angle encoder 113 is coupled to the shaft of the third gear 107c located at the last end of the reduction gear 106 that decelerates the rotation speed of the rotary shaft 104. The wide- Is an absolute type encoder that outputs a unique code value for an arbitrary rotation angle within one revolution of the third gear 170c whose rotation speed of the rotation shaft 104 is reduced by the reduction gear 106. [ That is, the third gear 107c makes one rotation when the rotation shaft 104 rotates several times according to the deceleration ratio with respect to the rotation shaft 104. The wide-angle encoder 113 rotates the third gear 107c , The eccentricity can be measured over a wide range corresponding to the number of rotations of the rotary shaft 104.

The values output through the precision encoder 112 and the wide-angle encoder 113 are transmitted to the absolute position measuring controller 200. The absolute position measuring controller 200 includes a rotary shaft 104 in which the precision encoder 112 is installed, The absolute position value according to the movement of the measurement object is calculated by analyzing the output values of the precise encoder 112 and the wide-angle encoder 113 in consideration of the deceleration rate and the backlash error of the third gear 107c provided with the encoder 113 .

The third gear 107c to which the wide-angle encoder 113 is coupled is provided with a detection disk 111 and a photoelectric sensor 109 for setting the absolute zero point of the precision encoder 112 and the wide-angle encoder 113 . The detection disc 111 is detachably fixed to a shaft of a third gear 170c to which the wide-angle encoder 113 is coupled through a fixing screw 108. The detection disc 111 is provided with a detection groove 114 And is made of a circular plate of opaque material. The photoelectric sensor 109 includes a light emitting element for outputting a beam to a detecting disk 111 that rotates together with the rotation of the shaft of the third gear 107c and a light emitting element for outputting the beam to the detecting groove 114 of the detecting disk 111, A light receiving element for receiving the light. The photoelectric sensor 109 is fixed to a sensor fixing plate 109a coupled to the shaft of the third gear 107c and passes through the detection groove 114 of the detection disc 111 through the photoelectric sensor 109 When the beam is received, the photoelectric sensor 109 transmits the beam reception signal to the absolute position measuring controller 200, and the absolute position measuring controller 200 sets the absolute position to the absolute zero position.

A gear for adjusting the zero point is formed on the circumference of the detection disk 111 and the adjustment gear 110 is coupled to the gear to adjust the position of the detection disk 111. That is, the detection disc 111 coupled to the axis of the third gear 107c can change its zero point position to set a correct zero point position. After moving the measurement object to the zero point position, The detection disk 111 is separated from the shaft of the third gear 107c by releasing the fixing screw 108 for fixing the shaft 103c to the shaft of the third gear 107c, The gear 110 is rotated so that the detection groove 114 of the detection disc 111 is rotated so as to reach the detection beam position of the photoelectric sensor 109 and then the detection disc 111 is rotated 3 gear 107c, as shown in FIG.

FIG. 2 is a cross-sectional side view of the absolute position measuring apparatus according to the embodiment of the present invention. Referring to FIG.

As shown in Figs. 1 and 2, a photoelectric sensor 109 for detecting a zero point position is installed in a sensor fixing plate 109a, which is coupled to the shaft of the third gear 107c by a bearing So as to support the photoelectric sensor 109 with the same center as the axis of the third gear 107c without affecting the rotation of the third gear 107c. An adjustment bearing 115 protrudes from the sensor fixing plate 109a and contacts the spindle 116 of the micrometer head 118 fixed to the fixing block 117 Tension is provided by the tension spring 109b so as to maintain the tightened state. The tension spring 109b is fastened to the hole formed in the body 101 at one side through the tension spring retaining ring 109c and is fastened to the hole formed at the sensor fixing plate 109a at the other side to fix the sensor fixing plate 109a to the spindle (116). As the spindle 116 of the micrometer head 118 advances or retracts, the adjustment bearing 115 also rotates left and right to rotate the sensor fixing plate 109a, and the sensor fixing plate 109a is rotated in the left- The photoelectric sensor 109 also rotates finely left and right around the axis of the third gear 107c so that the detection position of the detection groove 114 formed in the detection disc 111 can be precisely adjusted.

In the absolute position measuring apparatus 100 constructed as described above, the rotary shaft 104 rotates in accordance with the movement of the object to be measured, and the precision encoder 112 provided on the rotary shaft 104 in accordance with the rotation of the rotary shaft 104 And outputs an eigenvalue corresponding to the rotation angle within one rotation. The reduction gear 106 composed of the first gear 107a, the second gear 107b and the third gear 107c coupled to the rotation shaft 104 is rotated and rotated according to the rotation of the rotation shaft 104 And the wide-angle encoder 113 coupled to the last end of the reduction gear 106, that is, the third gear 107c axis, outputs an eigenvalue corresponding to the rotation angle within one rotation. The output values of the precision encoder 112 and the wide-angle encoder 113 are analyzed by the absolute position measurement controller 200 to calculate an absolute position value according to the movement of the measurement object.

Hereinafter, the process of calculating the absolute position value of the measurement object by analyzing the measured values of the precise encoder 112 and the wide-angle encoder 113 by the absolute position measurement controller 200 will be described.

The absolute position of the measurement object is obtained by calculating the number of revolutions of the precise encoder 112 using the value of the wide-angle encoder 113, multiplying the calculated number of revolutions of the precise encoder 112 by the resolution of the precise encoder 112, The value of the encoder 112 may be added.

First, the easiest way to calculate the number of revolutions of the precision encoder 112 is when the resolution of the precision encoder 112 is 1024, when the value of the precision encoder 112 is changed from 1023 to 0, The number of revolutions of the precision encoder 112 is decreased by 1 at the moment when the number of revolutions of the precision encoder 112 is changed from 0 to 1023. However, this method can not be applied because the number of rotations of the precision encoder 112 can not be calculated by reading the value of the wide-angle encoder 113 at the moment when the power is turned on. In this method, the number of revolutions before the power is turned off is stored in the backup memory, and when the power is supplied, the value is read to know the number of revolutions until the power is turned off. However, Since the amount of movement can not be calculated, it is impossible to apply to the absolute position measurement as a result.

FIG. 3 is a graph illustrating output values of a precision encoder and a wide-angle encoder according to an embodiment of the present invention.

3, the precision encoder 112 and the wide-angle encoder 113 have a resolution of 1024. When the precision encoder 112 makes one revolution, the value of the precision encoder 112 increases from 0 to 1023 The wide-angle encoder 113 is moved to the deceleration gear 106 as it is decelerated.

When the value of the precision encoder 112 is Enc_A, the value of the wide-angle encoder 113 is Enc_B, and the resolution of the precision encoder 112 and the wide-angle encoder 113 is 1024, the absolute position The value can be expressed by the following equation (1).

Figure 112016001277682-pat00005

Here, f (Enc_B) is a series of functions for calculating the number of rotations of the precision encoder 112 with the value Enc_B of the wide-angle encoder 113 as a variable. The value of f (Enc_B) .

The first gear 107a, the second gear 107b, the third gear 107c, and the third gear 107c in the process of calculating the number of revolutions of the precision encoder 112 using the value of the wide- There is a non-response region in which the value of the wide-angle encoder 113 does not change even if the rotation axis 104 rotates when the rotation direction of the rotation axis 104 is changed.

In most cases, the value of the wide-angle encoder 113 for one rotation of the precision encoder 112 is not an integer. For example, the first gear 107a, the second gear 107b, the third gear The value A1 of the wide-angle encoder 113 for one rotation of the precision encoder 112 is calculated by the following equation (2): " (1) " .

Figure 112016001277682-pat00006

Since the value of the wide-angle encoder 113 for one rotation of the precision encoder 112 is not an integer as in Equation (2) above, the value of the wide-angle encoder 113 is used because of the backlash existing between the gears, A complicated process is required to calculate the number of revolutions of the rotor 112.

First, backlash existing between gears will be described.

Fig. 4 shows an example of a general backlash formed between two gears. Assume that the amount of backlash between two gears is d ?.

Generally, backlash occurs at the time when the rotational direction of the rotating shaft 104 is changed. In the absolute position measuring apparatus 100 of the present invention, the amount of backlash and the gear ratio between the rotating shaft 104 and the first gear 107a are expressed by d? The backlash amount and the gear ratio of the first gear 107a and the second gear 107b are denoted by d? 2 and Gr2 and the amount of backlash and the gear bar between the second gear 107c and the third gear 107c are denoted by d? The total backlash amount ?? formed between the rotating shaft 104 and the third gear 107c can be expressed by the following equation (3).

Figure 112016001277682-pat00007

The total backlash amount [Delta] [theta] is converted into the value A2 of the precision encoder 112, and can be expressed by the following equation (4).

Figure 112016001277682-pat00008

FIG. 5 is a conceptual diagram for measuring the number of revolutions of a precise encoder using a wide-area encoder value according to a conventional method, FIG. 6 is a conceptual diagram for measuring the number of revolutions of a precise encoder using a wide- .

In general, the absolute position value of the measurement object is obtained by dividing the value of the wide-angle encoder 113 by a predetermined coefficient to calculate the number of revolutions of the precise encoder 112, multiplying the value by the resolution 1024 of the precise encoder 112, 112) are added to calculate the absolute position value. However, since the value of the wide-angle encoder 113 is outputted as an integer rather than a real number, a round-off error occurs in the calculation process, and the value of the precision encoder 112 is changed from 0 to 1023 or 1023 A large error of 1024 which is a positive (+) position error or -1024 which is a (-) position error occurs in the portion where 0 is changed.

In order to explain this more specifically, an Excel program is created, and the value of the precision encoder 112 is incremented by 1, four rotations, and then decremented by 1 in the opposite direction, A simulation for calculating the value of the encoder 113 was performed. Also, assuming that the backlash amount [Delta] [theta] is 15, the process of changing the value of the wide-angle encoder 113 due to the delay of signal transmission every time the direction of the precision encoder 112 increases or decreases Respectively. The simulation results for the continuous movement of the precise encoder 112 and the wide-angle encoder 113 are shown in the Excel program of Figs. 7 to 9.

The simulation items shown in Fig. 7 are classified into common items, general calculation, invention calculation, and precision encoder rotation number calculation table, and the respective items are as follows.

[Common Items]

In the common item, the B column is incremented by 1 or decremented by 1 to indicate a reference absolute position, the C column represents a process in which the value of the precision encoder 112 is incremented by 1 or decremented by 1, The backlash is expressed on the assumption that the backlash is shifted downward in an apparatus having a backlash amount (??) of 15. The row F represents the theoretical value of the wide-angle encoder 113 taking into account the influence of backlash, The value is expressed as a digital value like an actual encoder output by integrating.

[General calculation]

Column I of the general calculation item indicates the number of rotations of the precision encoder 112 calculated on the assumption that the value of the wide-angle encoder 113 is 972 and the gear ratio to the rotation axis 104 is 90: 1 in the entire stroke, and J Column represents the value of I column which is the number of revolutions of the precise encoder 112 multiplied by the resolution 1024 of the precise encoder 112 plus the value of the precise encoder 112 of the C column and the K column represents the value of the J column Absolute position_general) is subtracted.

[Invention calculation]

In the inventive calculation item, column M refers to the value of the theoretical wide-angle encoder 113, which is the value of the column G, to the number of revolutions of the precision encoder 112 according to Equation 17 described later with reference to the precision encoder rotation number calculation table 420 on the right side And N represents a downstep band value with respect to the number of revolutions of the precision encoder 112 displayed in the column M, and the column O determines whether down-step correction is to be performed according to the following equation (19) When the correction is performed, the value is indicated as 1. When the down-step correction is not performed, the value is indicated as 0. The P column indicates a value obtained by multiplying the number of revolutions of the precise encoder 112 displayed in the column M by the resolution 1024 of the precise encoder 112 plus the value of the precise encoder 112 in the column C, (Absolute position_invention) value in the column.

In the general calculation shown in FIG. 7, the value of the theoretical wide-angle encoder 113 is calculated and integerized for the entire process of incrementing the value of the precision encoder 112 displayed in column C by 1 or decrementing by 1, , The value of the G column is simply divided by the value of the wide-angle encoder 113 for one rotation of the precise encoder 112 to indicate the number of rotations of the precise encoder 112 in the I column, The resolution is multiplied by 1024, and the value of the precision encoder 112 is added to calculate the J-th column.

Further, the invention calculation is performed by calculating the number of revolutions of the M-column precision encoder 112 using the G column value, which is the theoretical wide-range encoder 113 value of the common item, by referring to the precision encoder rotation number calculation table 420, Which is obtained by multiplying the number of rotations of the precision encoder 112 by the resolution 1024 of the precision encoder 112 and adding the value of the precision encoder 112 of the C column. The U column indicates that the value of the precise encoder 112 is 0? 1023 or 1023 (?), And the U column indicates the step-up upper limit value. Step down compensation for eliminating the phenomenon that a large error is generated in the absolute position calculation at the portion where the change is made from 0 to? 0. In the down-step correction, in order to eliminate the occurrence of (+) position error or (-) position error in calculating the absolute position value at the portion where the value of the precision encoder described in FIG. 4 is changed from 0 → 1023 or 1023 → 0 , Subtracting 1 from the number of revolutions of the precise encoder 112 when the value of the wide encoder 113 is smaller than the value of the down step band and the value of the precise encoder 112 is larger than the down step lower limit value . In the practice of the present invention, the lower step lower limit value is set to a constant in the range of 0 to 0.75 of the resolution of the precision encoder 112. Hereinafter, the lower step lower limit value is 0.5, that is, 512 of the resolution of the precision encoder 112 A set example will be described.

Fig. 10 is a conceptual diagram of such a precision encoder rotation number calculation table.

A step-up lower limit value 306, a step-up upper limit value 308 and a down step band value 307 of the precision encoder rotation speed calculation table 420 are calculated as follows.

First, the value of the wide-angle encoder 113 is B1, and the number of revolutions of the precise encoder 112 is B2. At this time, if the value of the wide-angle encoder 113 per revolution of the precise encoder 112 is A3 , The above-described equation (2) can be modified as the following equation (5). In this case, the int function is used to convert the value (A3) of the wide-angle encoder 113 per rotation of the precision encoder 112 into an integer value in Equation (5), and 0.5 is added for rounding.

Figure 112016001277682-pat00009

The step-up lower limit value 306 for the number of revolutions N of the precise encoder 112 in the entire stroke and the step-up upper limit value 306 for the number of revolutions N of the precise encoder 112 in the entire stroke can be obtained by using the value A3 of the wide-angle encoder 113 per revolution of the precise encoder 112 (308) and the down step band value (307) are calculated through the following equations.

Figure 112016001277682-pat00010

Figure 112016001277682-pat00011

Figure 112016001277682-pat00012

Figure 112016001277682-pat00013

Here, A3 is the value of the wide-angle encoder per one rotation of the precision encoder of Equation (5), N is the number of rotations of the precision encoder, and int () represents a function of converting real numbers to integers. Also, α is a constant in the range of 0 to 0.499, β is a constant in the range of 0.5 to 0.999, γ is a constant in the range of 0 to 0.499, and δ is a constant in the range of 0 to 0.75.

7 and 10 based on the step-up lower limit value 306, the step-up upper limit value 308, the down-step band value 307, and the down-step lower limit value calculated through the above- 420. The precision encoder rotation number calculation table 420 shown in Figs. 7 and 10 shows an example in which? Is set to 0.25,? Is set to 0.75, and? Is set to 0.25. The step-up lower limit value 306 thus set is displayed in the column T, the step-up upper limit value 308 is displayed in the column V, and the downstep band value 307 is displayed in the column U. Although not shown in the precision encoder rotation speed calculation table 420, the case where δ for the lower step lower limit value is set to 0.5 will be described as an example.

In order to verify whether the present invention operates correctly with respect to the continuous movement of the precise encoder 112 and the wide-area encoder 113, each row number is sequentially increased in the Excel program of FIG. 7 showing the simulation result. The mathematical expressions show the item-specific simulation values displayed on the fourth line of each row of the Excel program.

Figure 112016001277682-pat00014

Figure 112016001277682-pat00015

Figure 112016001277682-pat00016

Figure 112016001277682-pat00017

Figure 112016001277682-pat00018

Figure 112016001277682-pat00019

Figure 112016001277682-pat00020

Figure 112016001277682-pat00021

Figure 112016001277682-pat00022

Figure 112016001277682-pat00023

Figure 112016001277682-pat00024

Figure 112016001277682-pat00025

Figure 112016001277682-pat00026

Figure 112016001277682-pat00027

In FIG. 8, for example, in the case where the left row number is 1982, the absolute position value of the B column B1982 is 1979, the precision encoder 112 value C1982 of the C column is 955 and the rotation number G1982 of the wide- 21. At this time, the value of the precision encoder 112 in the C column, in which the value of the precision encoder 112 is increased by one pulse and the row number is changed to 1983, is changed to 956.

[Example 1 (common), row = 1982]

8, the precision encoder 112 value C1982 of the column C is 955 and the revolution number I1982 of the precision encoder 112 of the column I is 1. Therefore, the absolute position value J1982 is calculated by the following equation And so on.

Figure 112016001277682-pat00028

Here, when the precision encoder value is increased by 1 and the row number is changed to 1983, the absolute position value will be compared with a general calculation method and a calculation method according to the present invention.

[ Example  1A (general calculation method), row = 1983]

The general calculation method is as follows. When the row number increases from 1983 to the precision encoder 112 value C1983 of the column C to 956, the revolution number G1983 of the wide band encoder 113 of the G column is changed to 22 and the precision encoder 112 of the general calculation item I1983 is calculated by the following equation according to the following equation (16).

Figure 112016001277682-pat00029

The absolute position value J1983 at this time is calculated by the following equation according to the equation (17).

Figure 112016001277682-pat00030

Thus, according to the general calculation method, the value of absolute position_general J1983 becomes 3004, which causes a large error of 1024, which is the (+) position error, between the value of absolute position_general J1982 and the value of K1983.

[Example 1B (invention calculation method), line = 1983]

According to the calculation of the present invention, since the number of revolutions of the wide-area encoder 113 is 22 in 1983 and the number of revolutions of the wide-area encoder 113 is 22, if the range to which this value belongs is found in the precision encoder revolution number calculation table 420, The upper limit value corresponds to 30 of V5 and the down step band value corresponds to U5 24, and it can be seen that the number of rotations of the precision encoder 112 corresponds to 2 in S5.

In this state, the value G1983 of the wide-angle encoder 113 is 22, and the number of rotations M1983 of the precision encoder 112 is 2. At this time, since the downstep band value U5 is 24, the value of G1983 22 is less than the value 24 of U5, the precision encoder value C1983 is 956, and the lower step lower limit value is larger than 512, the down step correction judgment O1983 becomes 1, and the down step correction should be applied.

Therefore, the absolute position value at this time is calculated by the following equation according to equation (22).

Figure 112016001277682-pat00031

Thus, it can be seen that the value of P1983 increases linearly with respect to P1982.

Therefore, according to the general calculation method, a large error of 1024, which is the (+) position error, occurs between the absolute position_normal J1982 value and the K1983 value. On the other hand, according to the present invention calculation, the value of P1983 is normally 1 Is increasing.

9 shows the result of calculating the absolute position value for the C column of the precision encoder 112 in a state where the value of the precision encoder 112 is decremented by one.

[Example 2 (common), row = 6447]

9, in the process of changing the precision encoder 112 value from C6447 to 1023 in the row number 6447, the C-column precision encoder 112 value C6447 is 0 and the I-column precision encoder 112 rotation Since the number I6447 is 2, the absolute position value J6447 is calculated according to the following Equation (17).

Figure 112016001277682-pat00032

Here, the absolute position value when the value of the precision encoder 112 decreases by one pulse and the row number becomes 6448 will be described by dividing the calculation method by the general method and the calculation method according to the present invention.

[ Example  2A (general calculation method), row = 6448]

In the general calculation method, the value of the precise encoder 112 in the column C is changed from 6448 to 1023 in the column number C6448, the number of revolutions G6448 of the wide-angle encoder 113 in the column G is not changed to 22, Since the rotation number I6448 is 2, the absolute position value J6448 is calculated by the following equation according to the equation (17).

Figure 112016001277682-pat00033

Thus, according to the general calculation method, the value of absolute position_general J6448 becomes 3071, which causes a large error of 1024 as in the case of absolute position_general J6447 and K6448.

[Example 2B (Inventive calculation method), row = 6448]

According to the calculation of the present invention, since the number of revolutions of the wide-area encoder 113 is equal to 22 and the number of revolutions of the wide-area encoder 113 is 22, if the range to which this value belongs is found in the precision encoder revolution number calculation table 420, The upper limit value corresponds to V5 of 30 and the down step band value corresponds to U5 24, and the number of rotations of the precision encoder 112 corresponds to 2 in S5.

The value G6448 of the wide-angle encoder 113 is 22, and the number of rotations of the precision encoder 112 is M6448 is 2, and since the downstep band value U5 is 24, the value of G6448 22 is less than the value 24 of U5 and the precision encoder value C6448 is 1023, which is greater than the downstep lower limit value of 512, and the downstep correction judgment O6448 becomes 1, and the downstep correction should be applied.

Therefore, the absolute position value at this time is calculated by the following equation according to equation (22).

Figure 112016001277682-pat00034

Thus, it can be seen that the value of P6448 is 1 linearly decreased compared to P6447.

Therefore, according to the general calculation method, a large error of 1024 is generated as in the case of the absolute position_general J6447 and the value of K6448. On the other hand, according to the calculation of the present invention, the value of P6448 is normally decreased by 1 as compared with P6447 .

7 to 10, in the present invention, the rotation speed of the precision encoder 112 is calculated by applying the step-up lower limit value, the step-up upper limit value and the down-step band value according to the value of the wide- (+) Position error or (-) position error at the portion where the rotation number of the precision encoder 112 is changed from 0 → 1023 or 1023 → 0 can be completely eliminated by calculating the absolute position value based on this, The absolute position value can be calculated.

Meanwhile, as another embodiment of the present invention, the wide-angle encoder 113 is replaced with a precision rotatable potentiometer, and the voltage value of the potentiometer is analog-to-digital converted and read at an arbitrary position, The number of rotations of the precision encoder 112 can be determined.

Hereinafter, the configuration and operation of the absolute position measuring controller 200, which receives signals output from the precise encoder 112 and the wide-angle encoder 113 through an interface and calculates an absolute position, will be described.

11 is a block diagram of an absolute position measuring controller according to an embodiment of the present invention.

11, the absolute position measuring controller 200 according to the present invention includes a precise encoder interface unit 202 to which a measurement signal is input from the precise encoder 112, And a microprocessor 201 for analyzing the measurement signals of the precise encoder 112 and the wide-angle encoder 113 and calculating an absolute position value. The absolute position measuring controller 200 includes a zero point signal input unit 206 for setting the zero point, a zero point permission signal input unit 207 for permitting the zero point change permission, a limit signal input unit 208 for limiting the operation range, A FRAM memory 205 in which various parameters and variables are stored, an RS-232C communication unit 209 and an RS-485 communication unit 210 for communication with an external device, A limit value output unit 211 for outputting an absolute position value to the outside, a limit signal output unit 212 for transmitting a limit signal for limiting the operation range of the apparatus to an external control device, Receiving unit 213, an Ethernet communication unit 215 for transmitting data in an Ethernet mode, and a wireless transmitting / receiving unit 216 for transmitting and receiving data in a wireless manner.

A precision encoder 112 is connected to the precision encoder interface unit 202. The precision encoder interface unit 202 adjusts the level of a signal input from the precision encoder 112, And converts the signal into a binary number and inputs the binary number to the microprocessor 201. Preferably, the time constant of the RC filter is designed to be at least two times higher than the maximum frequency of the precise encoder 112.

A wide-angle encoder 113 is connected to the wide-angle encoder interface 203. The wide-angle encoder interface 203 controls the level of a signal input from the wide-angle encoder 113, And converts the signal into a binary number and inputs the binary number to the microprocessor 201. It is preferable that the time constant of the RC filter is designed to be two times higher than the maximum frequency of the wide-angle encoder 113.

The microprocessor 201 analyzes an input signal through the precise encoder interface unit 202 and the wide-angle encoder interface unit 203 to calculate an absolute position value of the measurement object. In the microprocessor 201, A flash memory in which a program for analyzing measurement signals of the precision encoder 112 and the wide-angle encoder 113 is calculated to calculate an absolute position value, and an SRAM for storing various variables are provided. A USB port 204 is connected to the microprocessor 201. A notebook computer 130 is connected to the USB port 204 so that the notebook computer 130 and the microprocessor 201 can communicate with each other through a USB communication method. The notebook computer 130 transmits an operation program to the microprocessor 201 or transmits parameter values to be set.

The FRAM memory 205 is a nonvolatile memory whose contents are not erased even when the power is turned off. The FRAM memory 205 stores a parameter value transmitted from the notebook computer 130 or an external device, or stores important parameter values .

The zero point signal input unit 206 is provided with an optical isolator (photocoupler) to receive a signal input from the zero point switch 120 to isolate a signal. The chattering phenomenon of the switch is mitigated through an RC filter circuit, And transmits a signal to the microprocessor 201 by eliminating the chattering phenomenon of the signal due to the inversion of the signal or the thresholding function.

The zero point enable signal input unit 207 is provided with an optical isolating element to receive a signal input from the zero point enable switch 121 to isolate the signal and to mitigate the chattering of the switch through the RC filter circuit, And transmits a signal to the microprocessor 201 by excluding the chattering of the signal due to the inversion of the signal or the thresholding function.

The limit signal input unit 208 is a function for setting a limit position where the measurement object exceeds the movement range and should not be moved forward or backward. The limit switch 122, which is provided outside the absolute position measurement controller 200, And receives a signal from the upper limit switch or the lower limit switch. The limit signal input unit 208 receives a signal input from a plurality of limit switches or the like through an optical isolator as a signal in which an external power supply and an internal power supply are separated from each other, and mitigates chattering of the switch through an RC filter circuit And controls the signal level to eliminate the chattering phenomenon of the signal due to the inversion or thresholding function of the signal and transmits the signal to the microprocessor 201.

The RS-232C communication unit 209 is a circuit for communicating with an external device such as an external keyboard or an LCD display (LCD & Keyboard) 131. The RS-232C communication unit 209 communicates with the RS- And the operation state is displayed on the LCD display device, and the function of enabling the keyboard to be pressed or the state of the device and the alarm state to be displayed through the buzzer is also performed.

The RS-485 communication unit 210 is a communication circuit that performs a function of transmitting an absolute position value or an operation state value to the external position display device 132 by a half-duplex communication method. The RS- MODBUS-RTU or MODBUS-ASCII or CAN communication or CC-Link method, the signal is transmitted through the protocol such as PLC protocol specified in the parameter. The RS-485 communication unit 210 also performs a function of exchanging signals by radio such as CDMA, WIFI, ZIGBEE and the like by installing a media converter on the outside.

The position value output section 211 is a circuit for outputting the absolute position value calculated by the microprocessor 201 to the upper monitoring apparatus 133. The position value output section 211 outputs Or a voltage for driving the open collector device and outputs the voltage to a relay contact signal or an open collector output signal. As shown in FIG. 13, if the value is 1, the signal output through the position value output unit 211 is a BCD signal if the value is 1, a binary signal if the value is 2, The output is in the form of a gray code.

The position signal output unit 212 outputs a plurality of position signals. The position signal output unit 212 has a function of outputting a limit sensor signal input through the limit signal input unit 208 and a limit signal input unit 208 ), Para_Pos1 as a first parameter for outputting a first position signal for outputting a signal when the absolute position value reaches or exceeds a set parameter value, and a second position signal There is Para_Pos2 as the second parameter for outputting.

The DC / DC converter 214 converts the external DC 24V power supply 123 to DC 5V and supplies the converted DC 5V to the absolute position measuring controller 200.

The optical signal transmitting and receiving unit 213 is a circuit for receiving or outputting signals of a glass optic fiber or a plastic optic fiber. The optical signal transmitting and receiving unit 213 transmits and receives data to and from the outside through an external optical signal converting apparatus 135 and an optical fiber, And functions to protect the device by blocking the incoming surge signal.

The Ethernet communication unit 215 transmits data to the upper monitoring apparatus 133 through a protocol such as MODBUS-TCP using Ethernet as a medium, EtherCAT, EthernetIP, Profinet, or CC Link IE.

The wireless transceiver 216 is a communication device equipped with a module for transmitting and receiving data by using radio waves. The wireless transceiver 216 is a communication device that is equipped with a CDMA method, a Zigbee method, a WIFI method, an LTE method, To the device 136.

The absolute position measuring controller 200 configured as described above receives the zero point signal output from the zero point switch 120 through the zero point signal input unit 206 to set a zero point. That is, the absolute position measuring controller 200 sets a specific position as a zero point (origin point, reference point) and displays an absolute position value with reference to the zero point. The zero point, which is a reference of the absolute position value, It is set by operation.

When the zero point switch 120 is turned on, the ON signal is transmitted to the microprocessor 201 through the zero point signal input unit 206. In this case, When the ON signal of the zero point switch 120 is input to the microprocessor 201, the microprocessor 201 compares the value of the precise encoder 112 input through the precise encoder interface unit 202 with the value of the precoder 112 input to the wide- The values of the precise encoder 112 and the wide-angle encoder 113 inputted through the memory unit 203 are immediately stored in the precision encoder 112 zero value area and the wide-angle encoder 113 zero value area allocated to the FRAM memory 205 .

In the embodiment of the present invention, since the precision encoder zero value and the wide encoder zero value are important values based on the measurement, three consecutive values are stored, and in the process of reading the parameter after power supply, Even if the values of the two values are different, if the two values match, it is recognized as a correct value, thereby improving the reliability.

If the zero point value is set through the above process, the microprocessor 201 calculates a result value obtained by subtracting the zero value of the wide-angle encoder 113 from the value of the raw wide-angle encoder 113 input through the wide- And the value of the precision encoder 112 is also calculated by subtracting the precision encoder 112 zero value from the value of the raw precision encoder 112 input through the precision encoder interface unit 202 . That is, the value of the wide-angle encoder 113 and the value of the precise encoder 112 are calculated by the following equation.

Figure 112016001277682-pat00035

Figure 112016001277682-pat00036

On the other hand, when the measuring apparatus according to the present invention is used, the zero point switch 120 is inadvertently operated to set the current position of the apparatus as a zero point, the absolute position value of the apparatus is initialized, It also has a huge impact on the operation of the facility. In the present invention, in order to preclude such inadvertent setting of the zero point, only when the zero point setting switch 121 is set separately and the zero point setting is performed, the zero point enabling switch 121 is turned ON and is normally OFF, Even when the zero point switch 120 is input, the processor 201 prevents the zero point from being set inadvertently by setting the zero point when the zero point enable switch 121 is OFF.

When the zero point is set, the detection of the zero point position is performed through the detection plate 111 of an opaque material having the photoelectric sensor 109 and the detection groove 114. 1 and 2, when the detection groove 114 reaches the position of the light receiving beam and the light emitting beam of the photoelectric sensor 109 in the course of the rotation of the detection disc 111, the opaque detection disc 111 When the light of the light emitting element which has been blocked by the light receiving element reaches the light receiving element, the signal corresponding thereto is detected and set to the zero point position. When the zero point position is detected through the photoelectric sensor 109, the zero point position detection operation is output to the light or sound so that the user can easily confirm the zero point position detection operation.

A method for easily detecting a zero point position is to set a zero point at a position where the measurement object is moved to a desired zero point position. In this method, the detection disc 111 is rotated arbitrarily, Is rotated to the position of the detection beam of the photoelectric sensor 109. To this end, the fixing screw 108 is loosened so that the detection disc 111 is rotatably separated from the shaft of the third gear 107c, and the gear and the adjustment gear 110, which are formed in the circumference of the detection disc 111, The detection groove 114 is rotated to reach the detection beam position of the photoelectric sensor 109 and then the fixing screw 108 is fixed.

As described above with reference to FIG. 2, the adjustment bearing 115 is mounted on the sensor fixing plate 109a for fixing the photoelectric sensor 109. In this case, The photoreceptor 115 is brought into contact with the spindle 116 of the micrometer head 118 fixed to the fixed block 117 and rotated to the left or to the right by the forward or backward movement of the spindle 116, The detection position of the detection groove 114 in the detection disc 111 is adjusted so that the zero point can be detected more finely.

12 is a flowchart illustrating a process of measuring absolute position values through an absolute position measuring apparatus according to an embodiment of the present invention.

Step S100: When the measurement is started through the periodic interrupt (1 ms), the absolute position measuring controller 200 of the absolute position measuring apparatus 100 first calculates the value A of the wide-angle encoder 113, 113) The value A is a value obtained by subtracting the zero point value of the wide-angle encoder 113 set in the value A0 of the raw wide-angle encoder 113 input through the wide-angle encoder interface unit 203 as described in Equation 30 do.

Step S110: The precision encoder 112 value B is calculated as the zero point of the precision encoder 112 set in the raw precise encoder 112 value B0 input through the precise encoder interface unit 202 as described in Equation (31) Minus the value.

Steps S120 and S130: In order to calculate the absolute position value through the wide-angle encoder 113 value and the precision encoder 112 value calculated through the above process, the precision encoder 112 The step up index value, which is a value for finding the number of rotations, is set to 0 (S120), and the step up upper limit value, the step up lower limit value and the down step_band value for this step up index value are read (S130).

Steps S140, S141 and S142: Next, in order to determine the number of revolutions of the precision encoder, it is first determined whether the value A of the wide-angle encoder 113 is equal to or larger than the step-up lower limit value (S140). If the value of the wide-angle encoder 113 is equal to or greater than the step-up_lower limit value, the process proceeds to the next step S150. If the value of the wide-angle encoder 113 is smaller than the step-up_lower limit value, If the difference is greater than or equal to the predetermined value, the process proceeds to step S130. If the difference is greater than or equal to the predetermined value, the fine position calculation process is terminated (S142).

Step S150: It is determined whether the value of the wide encoder 113 is smaller than the step up_limit value. If the value of the wide encoder 113 is smaller than the step up_limit value, the process moves to the next step S160, The process proceeds to step S141 and the step up index value is incremented by one.

Step S160: The step-up index value is input as the number of rotations of the precision encoder 112. [

Step S170, S180 and S190: It is determined whether the value of the wide encoder 113 is smaller than the downstep band value to determine whether the down-step correction is applied (S170). If the value of the precision encoder 112 is small, (S180). If it is larger than the lower limit value, i.e., 512, the down-step correction is performed to subtract 1 from the rotation number of the precise encoder 112 (S190). On the other hand, if the value of the wide-angle encoder 113 is not larger than the value of the downstep band or the value of the precision encoder 112 is not larger than 512, which is the lower limit of the downstep, the downstep correction is not applied. The lower step lower limit value 512 is a value set to 0.5 of the precision encoder resolution when the resolution of the precision encoder 112 is 1024, which can be appropriately changed within the range of 0 to 0.75 of the precision encoder resolution.

Step S200: When the number of revolutions of the precise encoder 112 is calculated through the above process, the number of revolutions of the precise encoder 112 is multiplied by the resolution of the precise encoder 112 and the value of the precoder 112 To calculate the absolute position value, and then ends the cycle interruption.

13, the microprocessor 201 of the absolute position measuring controller 200 includes an LCD & Key board 131, a microprocessor (not shown) Or a parameter value from an external device via the USB port 204 or the RS-485 communication unit 210 and stores the parameter value in the FRAM memory 205. When the power is supplied, Initialize variables to implement various operations and functions.

13, Para_Unit for setting the operation unit to mm or cm, Para_Comp for setting whether to perform linear interpolation or circular interpolation, Para_Offset for setting a value for adding or subtracting the initial offset value to the operation value, Para_Output for setting the output format to BCD or binary, Para_Baud for setting the communication speed, Para_Ratio for setting the ratio of the absolute position value to the actual physical quantity 1000 mm, and the position value Para_Pos1 for outputting a signal when it is exceeded, and Para_Pos2 for outputting a signal when the absolute position value reaches or exceeds the set position_2.

As described above, in the present invention, the absolute position of a long distance can be measured through the precise encoder 112 and the wide-angle encoder 113. The value of the wide- The up-limit value and the down-step band value to determine whether the down-step is corrected, and calculates the absolute number of revolutions of the precision encoder 112 according to the determination result, So that it can be measured.

It is to be understood that the present invention is not limited to the above-described embodiment, and that various modifications and changes may be made by those skilled in the art without departing from the spirit and scope of the appended claims. Of course, can be achieved.

100: absolute position measuring device 101: body
102: cover 103: bearing
104: rotating shaft 105: rotating shaft gear
106: reduction gear 107a: first gear
107b: second gear 107c: third gear
108: fixing screw 109: photoelectric sensor
109a: Sensor fixing plate 109b: Tension spring
109c: tension spring fixing ring 110: adjusting gear
111: detection plate 112: precision encoder
113: wide-area encoder 114: detection groove
115: adjusting bearing 116: spindle
117: fixed block 118: micrometer head
120: Zero switch 121: Zero point switch
122: Limit switch 123: DC 24V power supply
130: Notebook computer 131: LCD & Key board
132: Position value display device 133: Upper monitoring device
134, 136: host controller 135: optical signal converter
200: absolute position measuring controller 201: microprocessor
202: precision encoder interface unit 203: wide encoder interface unit
204: USB port 205: FRAM memory
206: Zero point signal input unit 207: Zero point permission signal input unit
208: Limit signal input unit 209: RS-232C communication unit
210: RS-485 communication unit 211: Position value output unit
212: limit signal output unit 213: optical signal transmission /
214: DC / DC converter 215: Ethernet communication unit
216: radio transmitting /

Claims (16)

A precision encoder 112, which is an absolute encoder for precision measurement, which is coupled to a rotating rotary shaft 104 in accordance with the movement of the measurement object and measures and outputs a value according to the rotation angle of the rotary shaft 104; A reduction gear 106 that meshes with a gear 105 formed and decelerates the rotation speed of the rotation shaft 104 and an absolute type for wide area measurement that measures and outputs a value corresponding to a rotation angle decelerated by the reduction gear 106 An absolute position measuring controller 200 for analyzing the measured values of the precise encoder 112 and the wide-angle encoder 113 and calculating an absolute position value according to the movement of the measurement object, A position measuring apparatus comprising:
A detection disc 111 of an opaque material having a detection groove 114 for detecting a zero point is mounted on the axis of the gear on which the wide-angle encoder 113 is installed, and a detection disc 111, which rotates together with the rotation of the gear shaft, And a sensor fixing plate 109a provided with a photoelectric sensor 109 for detecting a zero point when the irradiated beam passes through the detection groove 114 of the detection disc 111,
The detection disc 111 is detachably coupled to the gear shaft via a fixing screw 108. A gear for adjusting the zero point is formed in the circumference of the detection disc 111. A detection mark is formed on the circumference of the detection disc 111 The formed gear is coupled to the adjusting gear 110 to rotate the adjusting gear 110 while releasing the fixing screw 108 to release the fixed state of the gear shaft and the detecting disk 111, Wherein the position of the zero point of the detection disc (111) can be changed by fixing the gear shaft and the detection disc (111) through the fixing screw (108) after adjusting the position of the detection disc (111).
The method according to claim 1,
The reduction gear 106 includes a first gear 107a that meshes with a rotary shaft gear 105 formed on a rotary shaft 104 and decelerates a rotation speed of the rotary shaft 104 and a second gear 107b that meshes with the first gear 107a, And a third gear 107c that meshes with the second gear 107b and decelerates the rotational speed of the second gear 107b,
Wherein a wide-angle encoder (113) is installed on an axis of a gear installed at a last end of the plurality of gears to measure a value corresponding to a reduced rotation angle.
The method according to claim 1,
Wherein the reduction gear (106) comprises an integrally formed reducer or a harmonic driver.
delete delete The method according to claim 1,
The adjustment bearing 115 is fixed to the upper portion of the sensor fixing plate 109a and the adjustment bearing 115 is fixed to the fixing block 117 installed on the body 101 of the absolute position measuring apparatus 100. [ The sensor fixing plate 109a is attached to the spindle 116 of the metering head 118 and rotates to the left or right by forward or backward movement of the spindle 116, 109a is rotated to the left or right so that the detection position of the detection groove 114 formed in the detection disc 111 can be finely adjusted.
delete The method according to claim 1,
The absolute position measuring controller 200 calculates the number of rotations of the precision encoder 112 using the value of the wide encoder 113 and outputs the resolution of the precision encoder 112 to the number of rotations of the calculated precision encoder 112 And then adds the value of the measured precision encoder 112 to calculate an absolute position value of the measurement object,
The absolute position measurement controller 200 checks the precision encoder rotation number calculation table 420 in which the step-up lower limit value, the step-up upper-limit value and the down-step-band value for each revolution of the precision encoder 112 are set , The table index value in the range in which the value of the wide-angle encoder 113 is greater than or equal to the step-up lower limit value of the precision encoder rotation speed calculation table 420 and smaller than the step-up upper limit value is set as the rotation speed of the precision encoder 112 If the value of the wide encoder 113 is smaller than the value of the down step_band value and the value of the precision encoder 112 is larger than the down step lower limit value, a down step correction is performed to subtract 1 from the set number of revolutions of the precision encoder 112 And calculates the number of revolutions of the precision encoder (112).
9. The method of claim 8,
The step-up lower limit value, the step up upper limit value, the down step band value, and the down step lower limit value of the precision encoder rotation speed calculation table 420 are set through the following equation.
[Mathematical Expression]
Figure 112016001277682-pat00037

Figure 112016001277682-pat00038

Figure 112016001277682-pat00039

Figure 112016001277682-pat00040

(Where A3 is the value of the wide encoder per rotation of the precision encoder, A3 = int (B1 / B2 + 0.5) where B1 is the value of the wide encoder in the entire stroke, B2 is the number of revolutions of the precision encoder with respect to B1, Α is a constant in the range of 0 to 0.499, β is a constant in the range of 0.5 to 0.999, γ is a constant in the range of 0 to 0.499, and δ is in the range of 0 to 0.75. Lt; / RTI >
A precision encoder 112, which is an absolute encoder for precision measurement, which is coupled to a rotating rotary shaft 104 in accordance with the movement of the measurement object and measures and outputs a value according to the rotation angle of the rotary shaft 104; A reduction gear 106 that meshes with a gear 105 formed and decelerates the rotation speed of the rotation shaft 104 and an absolute type for wide area measurement that measures and outputs a value corresponding to a rotation angle decelerated by the reduction gear 106 An absolute position measuring controller 200 for analyzing the measured values of the precise encoder 112 and the wide-angle encoder 113 and calculating an absolute position value according to the movement of the measurement object, A position measuring apparatus comprising:
The absolute position measuring controller 200 includes a precise encoder interface unit 202 to which a measurement signal is input from the precise encoder 112, a wide-range encoder interface unit 203 to which a measurement signal is input from the wide- A microprocessor 201 for receiving and analyzing the precise encoder measurement signal and the wideband encoder measurement signal through the precise encoder interface unit 202 and the wideband encoder interface unit 203 to calculate an absolute position value, A zero point signal input unit 206 for receiving a zero point setting signal from the microprocessor 120 and transmitting the zero point setting signal to the microprocessor 201 and a position value output unit 211 for outputting an absolute position value calculated through the microprocessor 201 Including,
The absolute position measuring controller 200 is provided with a zero point permission signal input unit 207 for receiving a zero point change permission signal from an external zero point enable switch 121 and transmitting the zero point change permission signal to the microprocessor 201, Controls the zero point setting to be performed only when the zero point permission signal is ON.
delete 11. The method of claim 10,
The microprocessor 201 receives parameter information from an external device through the LCD & Key board 131, the USB port 204, or the RS-485 communication unit 210,
The parameter information includes Para_Unit for setting an operation unit in mm or cm, Para_Offset for setting a value for adding or subtracting an initial offset value to an operation value, Para_Baud for setting a communication speed, and an absolute position value And Para_Pos1 and Para_Pos2 for outputting a signal when the absolute position value reaches or exceeds the set position value.
11. The method of claim 10,
The microprocessor 201 transmits the calculated absolute position value to the RS-232C communication unit 209, the RS-485 communication unit 210, the optical signal transmission / reception unit 213, the Ethernet communication unit 215, and the wireless transmission / And transmits the result to an external apparatus by using at least one of them.
delete delete delete
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