JP2581804B2 - Moving distance measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a finger speed signal generator, such as a linear encoder and a rotary encoder, for generating an electric signal of one cycle for a predetermined small amount of linear motion or rotational motion. With respect to the movement amount measuring device used, in particular, the first and second sets of two sets having a phase shift of 90 ° in one cycle with respect to the movement of the movement amount measurement target material such as linear movement and rotation movement in a predetermined unit. The present invention relates to a movement amount measuring device that uses an electric signal generator that generates an electric signal.

[Conventional technology]

Conventionally, this type of measuring apparatus binarizes first and second electric signals to shape them into first and second electric pulses, and a direction for detecting a moving direction from the first and second electric pulses. It has a detection means and an up / down counter that counts up the first electric pulse when the moving direction is one of the forward and reverse directions and counts down when the moving direction is the other. The count data of the counter indicates the movement amount.

When the electric signal generator is, for example, one in which a light source and two sets of photosensors are installed with a moving slit plate having a light-transmitting slit formed at a predetermined pitch and a fixed slit plate interposed therebetween, the moving amount (count data) is The minimum unit is one pitch of the light-transmitting slit, and a fractional value (less than one pitch) cannot generally be measured. However, during the movement of one pitch, the first and second electric signals each show a level change of one cycle. Therefore, the fractional moving amount is calculated based on the level of these signals, and the fractional moving amount data is calculated. Can also be obtained. One such type of moving amount measuring device that calculates a fraction is disclosed in Japanese Patent Publication No. 62-57930.

[Problems to be solved by the invention]

When the level of the electric signal generated by the electric signal generator fluctuates, for example, when the light amount or the light intensity of the light source fluctuates, the calculated value of the fractional movement amount fluctuates with this, and the measurement accuracy of the fraction is low.

Further, the above-described up / down counter is omitted, a fraction value is calculated from the level of the electric signal generated by the electric signal generator, and when the fraction value increases to a value corresponding to one pitch amount, the pitch amount detection value is calculated. When the fractional value is updated to 1 larger value and the fractional value is set to 0, and when the fractional value decreases from 0 in the negative direction, the pitch amount detection value is updated to 1 smaller value. If the calculation requires a relatively long time and the moving speed is high, the following speed of the measured moving amount to the actual moving amount is low.

Using the up / down counter described above and arithmetic processing means for calculating a fractional value from the level of the electric signal generated by the electric signal generator, the pitch amount is obtained from the count data of the counter. If only the numerical data is calculated, the arithmetic processing means for calculating the pitch amount by the arithmetic processing means is omitted, and the speed of following the measured movement amount with respect to the actual movement amount is increased. However, up /
It is impossible on the electric circuit and in the arithmetic processing to completely match the timing at which the down counter counts up / down with the timing at which the arithmetic processing means calculates the fractional value 0, and the up / down counter counts up. / In a very narrow range including the timing of down,
For example, when the arithmetic processing means calculates the fractional value 0, the up / down counter still counts up (or down).
When the up / down counter counts up (or down), or when the up / down counter counts up (or down), a change in the pitch movement amount such as a calculation value of the arithmetic processing means being a value different from the fractional value 0. The change in the fractional value does not match, which results in a measurement error of approximately one pitch. Such an error only occurs within a very narrow range including the timing at which the up / down counter counts up / down, but it becomes a problem because it appears every movement of one pitch.

For example, the moving amount measuring device disclosed in Japanese Patent Publication No. Sho 62-57930 calculates fractional values 0 to 9 based on the levels of an up / down counter and two sets of electric signals generated by a linear encoder having a 90 ° phase difference. The gate circuit 30 compares the two sets of electric signals to determine whether one electric signal (b) is in the first half area or the second half area of the area between the zero cross points (180 ° range). When the logical product of the first half area and the fractional value of any of 0 to 4 is established, the up / down counter is counted up, and the second half area and the fractional value of any of 5 to 9 are determined.
The up / down counter is down-counted when the logical product of is established. According to this, the timing of the up / down count is changed from the fractional value 9 → 0 or 0.
→ There is a case where it does not match with the switching of 9, and the continuity of the measured value is lost.

That is, when the fractional value progresses to 8, 9, 0, 1 and 1, the up / down counter counts up from the value n to n + 1 by one, and the up switching of the cue data (pitch data) occurs at the fractional value 1. The measured value is calculated from [n (number of pitches) + fraction 1] to [n + 1 (number of pitches) + fraction 1].
Switch to. It should be noted that the measured value is switched from [n (pitch number) + fraction 9] to [n (pitch number) + fraction 0] immediately before that, and the range of fraction 0 to 9 corresponds to one pitch. , The measured value (the number of pitches + the fraction) shows an instantaneous change of one pitch twice before and after one zero cross point. When the fractional value has progressed to 2,1,0,9 and 9, the up / down counter counts down by 1 and the count data is switched down at the fractional value of 9, and the measured value is [n (Pitch number) + fraction 9] is switched to [n-1 (pitch number) + fraction 9]. It should be noted that the measured value switches from [n (pitch number) + fraction 9] to [n (pitch number) + fraction 0] immediately before that, and the range of fraction 9 to 0 corresponds to one pitch. , The measured value (the number of pitches + the fraction) shows an instantaneous change of one pitch twice before and after one zero cross point.

Another object of the present invention is to provide a movement amount measuring device that measures a pitch movement amount and a fractional value thereof with high accuracy, and in which a measurement value continuously changes with respect to a continuous movement of a movement amount measurement target. .

[Means for solving the problem]

The measuring apparatus according to the present invention is coupled to a movement amount measurement object and has two sets of first and second phases that are 90 ° out of phase with each other in one cycle with respect to a movement such as a linear movement or a rotation movement in a predetermined unit. Electric signal generators (1-4x, 4y) for generating electric signals of the following; first and second amplifying means (5x, 5y) for amplifying the first and second electric signals, respectively; first and second Amplification means (5
A / D conversion means (7) for converting the level of the signal (Lc, Ls) amplified by (x, 5y) into first and second digital data, respectively; a mean square of the first and second digital data is set The first and second amplification means (5x, 5
signal level adjusting means (8) for adjusting the amplification factor of y); trigonometric function value calculating means (8) for calculating the ratio of the first and second digital data; ratio calculated by the trigonometric function value calculating means (8) Means (8) for converting the angle (θ) represented by the correlation between the levels of the first and second electric signals into data (Rd); The direction of movement of the movement amount measurement object and a predetermined angle (0
゜) The passage of the corresponding value (0) is detected, and when the detected moving direction is one direction (clockwise) at the time of passing the predetermined angle corresponding value, the pitch movement amount information (CS) is increased by one pitch equivalent value. Counting means (8) for updating to a value and, in the other direction (counterclockwise), to a value smaller by one pitch equivalent value; and from pitch movement amount information (CS) and angle-corresponding data (Rd), A movement amount information calculating means (8) for generating information (TR) including the pitch movement amount (CS) and the movement amount within one pitch (Rd); The symbol in parentheses is
The corresponding elements of the embodiment shown in the drawings and described later are shown.

[Function 1] A trigonometric function value calculating means (8) calculates a ratio between the first and second digital data, and converts this ratio into an inverse converting means (8).
Is converted into data (Rd) corresponding to the angle (θ) represented by the correlation between the levels of the first and second electric signals, so that the first and second electric signal generators (1 to 4x, 4y) generate the first and second electric signals. Even if the levels of the two electric signals change in the same direction, the ratio does not substantially change, and there is no change in the data (Rd). Therefore, the measurement of the fractional value (Rd) becomes accurate. If the level of the first and second electric signals fluctuates greatly, an error in the conversion into digital data increases due to the resolution of the A / D conversion, which also affects the calculation ratio. The adjusting means (8) adjusts the amplification factors of the first and second amplifying means (5x, 5y) so that the root mean square of the first and second digital data becomes a set value. An error in the conversion into digital data due to the conversion resolution is small, the ratio is calculated with high accuracy, and the fractional value (Rd) is accurately measured.

Since the measurement of the fractional value (Rd) is accurate, the calculation of the pitch movement amount based on the fractional value (Rd) by the counting means (8) also becomes accurate, and therefore, the pitch movement amount and the fractional value are obtained with high accuracy. Measured.

In addition, the counting means (8) determines the direction (clockwise / counterclockwise) of the movement of the movement amount measurement target and the value corresponding to the predetermined angle (0 °) based on the time-series transition of the angle-corresponding data (Rd). 0) The passage is detected, and at the time of passing the value corresponding to the predetermined angle, when the detected movement direction is one direction (clockwise), the pitch movement amount information (CS) is updated to a value larger by one pitch, In the other direction (counterclockwise), the pitch is updated to a value equivalent to one pitch smaller, so that the switching of the angle-corresponding data (Rd) and the switching of the pitch movement amount information (CS) are synchronized, and this pitch movement is performed. The measured value (CS + Rd) does not cause an instantaneous change of one pitch at the time of switching of the amount information (CS), and the measured value continuously changes with the continuous movement of the movement amount measurement object. .

[Means 2 for Solving the Problems] The measuring device of the present invention is coupled to a movement amount measurement object, and has one cycle with respect to movement such as linear movement and rotation movement of a predetermined unit.
Two sets of electric signal generators (1 to 4x, 4y) for generating first and second electric signals 90 ° out of phase with each other; a first and a second pulse for the first and second electric signals Signal (A, B)
Binarizing means (6); binarizing means (6); direction detecting means (10) for generating, from the first and second pulse signals (A, B), a direction signal representing the direction of movement of the movement amount determination target; Up / down counting up one (A) of the first and second pulse signals (A, B) when the signal is in one direction (clockwise), and counting down when the signal is in the other direction (counterclockwise). Counter (11); first and second amplifying means (5x, 5) each amplifying the first and second electric signals.
y); A / D conversion means (7) for converting the level of the signal amplified by the first and second amplifying means (5x, 5y) into first and second digital data, respectively; Trigonometric function value calculating means (8) for calculating a ratio of digital data;
Inverting means (8) for converting the ratio calculated by the trigonometric function value calculating means (8) into data (Rd) corresponding to the angle (θ); including the timing at which the up / down counter (11) counts up / down. In the immediate area (Ar), the direction of movement of the movement amount measurement target and the passage of the predetermined angle (0 °) corresponding value (0) are detected from the time-series transition of the angle-related data (Rd),
When the detected moving direction is one direction (clockwise) at the time of passing the predetermined angle corresponding value, the pitch moving amount information (CS) is updated to a value larger by one pitch, and the other direction (counterclockwise). )), Counting means (8) for updating to a value smaller by one pitch equivalent value; and, in the immediate area (Ar), pitch movement amount information (CS) and data (R) corresponding to the angle.
From d), information (TR) including the pitch movement amount (CS) and the movement amount within one pitch (Rd) is generated. Outside the immediate area (Ar), the count data (Rp) of the up / down counter (11) is generated. Information (TR) including the pitch movement amount (Rp) and the movement amount within one pitch (Rd) from the data (Rd) corresponding to the angle and the angle.
And a movement amount information calculation means (8).

[Operation 2] In a wide range outside the immediate area (Ar) including the timing at which the up / down counter (11) counts up / down, the movement amount information calculating means (8) uses the up / down counter (11) From the count data (Rp) and the data corresponding to the angle (Rd), information (TR) including the pitch movement amount (Rp) and the movement amount within one pitch (Rd) is generated. Since the pitch movement amount calculation processing such as the determination of the need to count up / down the pitch movement amount is unnecessary, and the counting by the up / down counter (11) is fast, the movement amount measurement value with respect to the actual movement amount is obtained. Tracking accuracy is high. In the immediate area (Ar) including the timing at which the up / down counter (11) counts up / down, the counting means (8) determines the direction of movement of the movement amount measurement target from the transition of the data (Rd) corresponding to the angle. , A predetermined angle (0 °) corresponding value (0) passing is detected,
When the detected moving direction is one direction (clockwise) at the time of passing the predetermined angle corresponding value, the pitch moving amount information (CS) is updated to a value larger by one pitch, and the other direction (counterclockwise). In the case of ()), the pitch amount is updated to a value that is smaller by one pitch, and the movement amount information calculating means (8) calculates the pitch movement amount (CS) and 1 by the pitch movement amount information (CS) and the data (Rd) corresponding to the angle. Information (TR) including the movement amount within the pitch (Rd)
Is generated, the switching of the pitch movement amount information (CS) and the change of the movement amount within one pitch (Rd) are matched (linked), and a measurement error of approximately one pitch does not occur between the two. That is, the switching of the angle-corresponding data (Rd) and the switching of the pitch movement information (CS) are synchronized, and the measured value (CS + Rd) for one pitch at the time of the switching of the pitch movement information (CS). There is no instantaneous change, and the measurement value changes continuously with the continuous movement of the movement amount measurement object.

The above-mentioned pitch movement amount information (CS) of the counting means (8)
Takes a relatively long time, but since the region (Ar) in which this is performed is in a very narrow range, the tracking performance of the time-series average of the measuring apparatus does not significantly decrease.

In a preferred embodiment of the present invention, the trigonometric function value calculating means compares the first and second digital data and determines that the direction (angle) of the combined vector is No. 0: 0 ° or more and less than 45 °, No.1: 45 to 90 ゜, No.2: 90 to 135 ゜, No.3: 135 to 180 No, No.4: 180 to less than 225 ゜, No.5: 225 ゜No. 6: More than 270 mm and less than 315 mm, No. 7: More than 315 mm and less than 360 mm, and when it is detected as No. 3, 4 or 7, it corresponds to the tangent value , The ratio of the absolute value of the first and second digital data is calculated, and when it is detected as No. 1, 2, 5, or 6, the absolute value of the first and second digital data corresponds to the reciprocal of the tangent value Shall be calculated.

The electric signal (Ls = Sinθ + Vsm, Lc = Cosθ + Vsm) amplified by the first and second amplifying means (5x, 5y) is equal to the reference voltage V
The level (vertical axis) shown in FIG. 2a is shown for sm. One cycle of this level is one pitch. Electric signal generator (1 to
4x, 4y) and the amplifying means (5x, 5y) are ideally designed, or are calibrated by adjusting the amplification factor of the amplifying means (6y, 6x), as shown in FIG. 2a. When the extreme values of the first and second electric signals (La = Sinθ + Vsm, Lc = Cosθ + Vsm) are equal and ideal Sin and Cos functions appear, as shown in FIG. 4, the first and second electric signals The direction θ of the composite vector (proportional to the fractional amount of movement in the pitch) is 0 to 360 ° divided into eight equal quadrants 0 to 7.
(FIG. 3). Assuming that the quadrant is set in this way and that the quadrant is located in θ, focusing on the absolute value of the fluctuation level (Ls = Sinθ, Lc = Cosθ) of the electric signal, it is as shown in FIG. 2b. .

In the No. 0 quadrant, Tanθt = | Sinθ | / | Cosθ | = | Ls | / | Lc |, so | Ls | / | Lc | is calculated, and this is regarded as the value of Tanθt. Arc tangent), θ
t is calculated, and this is obtained as a detection angle θ.

In the No. 1 quadrant, as shown by the arrow in FIG. 2b, looking at the angle of 90 ° as the starting point, the | Ls | and | Lc |
The angle in the decreasing direction can be calculated by exchanging That is, Tanθct = | Cosθct | / | Sinθct | = | Lc | / | Ls | is calculated as the value of Tanθct, and θct is calculated by inverse transformation (arc tangent), and θ = 90 ° −θct and the angle θ can be obtained.

In the No. 2 quadrant, as shown by the arrow in FIG. 2b, looking at 90 ° as the base point and looking at the angle increasing direction, | Ls | and | Lc |
The angle in the increasing direction can be calculated in a form where? That is, Tanθct = | Cosθct | / | Sinθct | = | Lc | / | Ls | is calculated as the value of Tanθct, and θct is calculated by inverse transformation (arc tangent), and θ = 90 ° + Θct and the angle θ can be obtained.

In the No. 3 quadrant, as shown by the arrow in FIG. 2b, the angle in the decreasing direction can be calculated in the same manner as in the case of the No. 0 quadrant when viewed in the angle decreasing direction from 180 ° as a base point. That is, Tanθt = | Sinθt | / | Cosθt | = | Ls | / | Lc | is calculated as the value of Tanθt, and θt is calculated by inverse transformation (arc tangent), and θ = 180 ° −θt and the angle θ can be obtained.

In the No. 4 quadrant, as shown by the arrow in FIG. 2b, the angle in the increasing direction can be calculated in the same manner as in the quadrant of No. 0 when viewed from 180 ° as the base point in the angle increasing direction. That is, Tanθt = | Sinθt | / | Cosθt | = | Ls | / | Lc | is calculated as the value of Tanθt, and θt is calculated by inverse transformation (arc tangent), and θ = 180 ° + Θt and the angle θ.

In the No. 5 quadrant, as shown by the arrow in FIG. 2b, when looking at the angle decrease starting from 270 °, | Ls | and | L of the No. 0 quadrant
The angle in the decreasing direction can be calculated by exchanging c |.
That is, Tanθct = | Cosθct | / | Sinθct | = | Lc | / | Ls | is calculated as the value of Tanθct, and θct is calculated by inverse transformation (arc tangent), and θ = 270 ° −θct and the angle θ can be obtained.

In the No. 6 quadrant, as shown by the arrow in FIG. 2b, looking at the angle increase from 270 °, the | Ls | and | L of the No. 0 quadrant
The angle in the increasing direction can be calculated by exchanging c |.
That is, Tanθct = | Cosθct | / | Sinθct | = | Lc | / | Ls | is calculated as the value of Tanθct, and θct is calculated by inverse transformation (arc tangent), and θ = 270 ° + Θct and the angle θ can be obtained.

In the No. 7 quadrant, as shown by the arrow in FIG. 2b, the angle in the decreasing direction can be calculated in the same manner as in the quadrant of No. 0 when viewed in the direction of decreasing angle from 360 ° as the base point. That is, Tanθt = | Sinθt | / | Cosθt | = | Ls | / | Lc | is calculated as the value of Tanθt, and θt is calculated by inverse conversion (arc dangent), and θ = 360゜ −θt and the angle θ can be obtained.

By performing the calculation in this manner, θt and θct are in the range of 0 to 45 °, and the data for performing the inverse calculation of the angle from the trigonometric function value (tangent) need only be for one quadrant (0 to 45 °). Since the data amount is extremely small, the angle resolution can be increased accordingly and the angle θ can be calculated with high resolution. In a preferred embodiment described later, one quadrant (0 to 45 °: 1/8 of the pitch) is set to 1
The angle θ (the numerical value at the end of the pitch) is expressed in units of 024 divisions.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

〔Example〕

FIG. 1 shows an embodiment of the present invention. The electric signal generator is composed of a light source 8, a movable slit plate mechanically coupled to the moving amount measurement object and reciprocating in the direction of the arrow in conjunction with the reciprocating linear movement, forward and reverse rotation of the moving amount measurement object 1, fixed. It comprises a slit plate 2 and first and second photosensors 4y and 4x. In the movable slit plate 1 and the fixed slit plate 2, light-transmitting windows having substantially the same pitch are formed at a predetermined pitch in the moving direction indicated by the arrow. The photo sensors 4y and 4x receive the light passing through the light transmitting windows of the slit plates 1 and 2,
One photosensor generates a sinusoidal (or cosine) electric signal generated by one of the photosensors when the movable slit plate 1 moves by one pitch. The relative positions of the two photosensors 4y and 4x in the direction of the arrow are set so as to generate (sine wave) electric signals.

The electric signals generated by the photo sensors 4y and 4x are amplified by the variable gain amplifiers 5y and 5x, respectively, and are amplified by the comparator 6 and the A / D.
It is provided to converter 7.

The comparator 6 converts the amplified electric signal into a reference electric Vsm.
To generate pulse signals A and B, which are supplied to the direction detector 10. It should be noted that the comparator 6 has a hysteresis characteristic, and, more precisely, performs binarization at a potential slightly shifted from the reference potential Vsm.

The direction detector 10 detects that the movable slit plate 1 moves in the backward direction when the signal A falls from H to low level L when the signal B is at the high level H based on the level change of the pulse signals A and B. When the signal A rises from L to H while the signal B is at the high level H, the movable slit plate 1
Is supplied to an up / down instruction signal input terminal (UP / DOWN) of the up / down counter 11 as an L signal indicating that it is moving in the forward direction (Q output of the flip-flop). The signal A is inverted by the inverter of the direction detector 10 and applied to the count pulse input terminal (CK) of the up / down counter 11.

When the direction signal is L (forward movement), the up / down counter 11 starts the signal A from L to H (signal A).
When the direction signal is H (backward movement), the count-up is performed by one in response to the fall of the signal A from H to L. The count data of the counter 11 is given to a microprocessor (hereinafter referred to as CPU) 8. A reset signal (L indicates reset) is applied to the clear signal input terminal (CLR) of the counter 11 and the CPU 8, and the reset signal is
, The up / down counter 11 sets the count data to 0.
And the count up / down operation is performed after the reset signal returns to H.

Since the comparator 6 has a hysteresis characteristic, the electric signal Ls = Sinθ generated by the variable gain amplifier 5y
When the signal A rises from L to H (falls from H to L) when the variation Sinθ of + Vsm is 0, the counter 11 should count up (down) there. This rising (falling) is caused by the extremely narrow region Ar (−) shown in FIG. 2a.
Within the range of Ld <Sinθ <Ld), the timing is shifted from the timing of Sinθ = 0, so that the count-up / down timing of the counter 11 does not exactly match Sinθ = 0.

The A / D converter 7 converts the electric signals Ls = Sinθ + Vsm, Lc = Cosθ + Vsm generated by the variable gain amplifiers 5y and 5x into digital data based on the reference potential Vsm, so that the conversion data of the converter 7 is Ls = Sinθ , Lc = Cos θ.

The CPU 8 sends the signal Ls to the A / D converter 7 with the required timing.
Ls = Sinθ and Lc
Digital data of c = Cosθ is obtained.

The variable gain amplifiers 5y and 5x can adjust the ratio of the output signal level (the potential fluctuating from the reference potential Vsm) to the input signal level (the fluctuating potential from the reference potential Vsm). Each time the CPU 8 instructs an up (or down), the gain is stepped up (down) by a minimum.

The CPU 8 is connected to a display unit 9 having a three-digit character display for displaying the light emission intensity of the light source 3 and an eight-digit character display for displaying the movement amount.

The CPU 8 is also connected to a key switch HS for stopping the change of the display value during display reading. In addition, the CPU 8 is connected with key switches and the like for calibrating the display value and adjusting the reference gain, the upper and lower limits of the variable gain amplifier, and the like, but these are not shown.

In this embodiment, as shown in FIG.
Ls = Sinθ and Lc during the movement of the light-transmitting window by one pitch
= Cosθ The angle of the composite belt in the range of 0 to 360 ° (that is, one pitch) (the pitch fraction value) is represented by decimal 0
Calculate with the value of ~ 8192, these values (0-8192)
It is converted to an angle value of 360 ° (pitch fraction value) to display a 4-digit fraction (decimal point or less) and a 4-digit pitch number (decimal point or more).

FIG. 5 shows the movement amount measurement operation of the CPU 8. When the power is turned on, the CPU 8 clears its internal registers, counters, timers, and the like, and provides the display unit 9 with data (display clear) for displaying all digits 0 (SIN). Next, a reset signal is given to the variable gain amplifiers 5y and 5x, and then reference gain data Gm is given (AIN). The variable gain amplifiers 5y and 5x set the gain to the base value (lowest value) in response to the reset signal, and then, when receiving the reference gain data Gm, increase the gain by one minimum unit (step).
The number of times of the increase is counted up, and when the count value reaches Gm, the change of the gain is stopped there.

Thereafter, when the key switch HS is open, the CPU 8 alternately repeats "gain setting of the amplifiers 5x and 5y" (AGA) and "measurement of the movement amount" (MDD). When a reset signal (= L) arrives from the outside, the up / down counter 11 clears itself (count value = 0) in response to this, and the CPU 8 responds to the reset signal (= L) to calculate at that time. The stored fractional value Rd is written to the initial value register (internal register) Rdi (3, 4), the display data TR of the display value register TR is cleared to 0, and this is displayed on the display 9. (4,5).

In “gain setting of amplifier 5” (AGA), Ls = Sinθ and Lc = Cosθ are converted into digital and read, and the sum of the squares (square of the polar coordinate radius) Rds is set in a setting range (Rss−A <Rd).
The gain of the amplifier 5 is adjusted so that s <Rss + B), and the light emission intensity = gain × √Rds is calculated and displayed on the three-digit character display of the display unit 9 for displaying the light emission intensity.

In “Measurement of travel distance” (MDD), Ls = Sinθ and Lc =
Digitally converts and reads Cos θ, determines which of the quadrants Nos. 0 to 7 of the eight equal division shown in FIG. 3 belongs to, and calculates an angle θ based on the determination result. The calculated angle θ is converted into a numerical value Rda ₁ below the decimal point, and the value obtained by subtracting the content of the initial value register Rdi from this is displayed on the 4-digit character display of the display unit 9 for displaying a fraction. In addition, it is determined whether or not the fractional value Rda ₁ is within a predetermined range Ar shown in FIGS. 2A and 3. If the fractional value Rda ₁ is out of the range, the integer value (pitch amount) of the display unit 9 is displayed. The count value of the counter 11 is displayed on the 4-digit character display. When it is within the range Ar, the transition of the fractional value Rda ₁ is detected, and when it crosses 0 in the forward direction, the content of the pitch count register CS is updated to 1 larger value, and when it crosses in the forward direction, the content of the register CS is updated. Is updated to one smaller value, and the data CS of the register CS is displayed on the 4-digit character display of the display unit 9 for displaying an integer value.

The "gain setting of the amplifiers 5x and 5y" (AGA) and the "movement amount measurement" (MDD) are alternately repeated, and when the measured value changes, the display of the display unit 9 changes and the display character flickers. When confirming the display correctly, the operator closes the key switch HS. While HS is Hei, CPU8 is "gain setting of amplifier 5x, 5y" (AGA) and "measurement of travel distance"
Since both (MDD) are stopped and waiting for the HS to open, the display unit 9 keeps displaying the measured value immediately before the HS is closed, and the display value does not change. When the HS returns to the open state, the CPU 8 alternately repeats “gain setting of the amplifiers 5x and 5y” (AGA) and “measurement of the movement amount” (MDD).

FIG. 6a shows the contents of “gain setting of amplifiers 5x and 5y” (AGA). When proceeding to “gain setting of amplifiers 5x and 5y” (AGA), the CPU 8 converts Ls = Sinθ and Lc = Cosθ into digital form and reads them (1, 2), and calculates the sum Rds of their squares (3). It is checked whether it is within the setting range (Rss-A <Rds <Rss + B) (4, 7).

If it is outside the lower limit of the setting range, it is checked whether or not the sum of the gain G currently set to the amplifier 5 plus 1 is equal to or more than the gain upper limit Gt (5). And instruct the amplifier 5 to step up to 1 and update the contents of the gain register (internal register) G to the sum G + 1 obtained by adding 1 to the value at that time (6), and Ls = Sinθ and Lc = Cosθ Is converted to digital and read (1, 2). Thus, the gain G is sequentially increased. When the gain becomes equal to or more than the upper limit Gt, the increase of the gain is stopped there, and the digital data of Ls = Sinθ and Lc = Cosθ at that time
The root mean is multiplied by the gain G at that time, the obtained value Mf is given to the display unit 9, and the updated value is displayed on the character display for displaying the light emission intensity (10, 11). Then, the gain is set to the upper limit Gt (12), and the main routine (fifth
Return to figure) (Go to MDD).

If the sum Rds is outside the upper limit of the setting range (Rss-A <Rds <Rss + B), it is checked whether the value obtained by subtracting 1 from the gain G currently set in the amplifier 5 is equal to or less than the gain lower limit Gb. (13), if it exceeds the lower limit Gb, the amplifier 5
, The content of the gain register G is updated to a residual value G−1 obtained by subtracting 1 from the value at that time (14), and Ls = Sinθ and Lc = Cosθ are converted to digital and read. (1,2). In this way, the gain G is sequentially reduced. When the gain becomes equal to or less than the lower limit Gb, the gain stop is stopped there, and then Ls = Sinθ and Lc
Multiply the mean square of the digital data of = Cosθ by the gain G at that time, give the obtained value Mf to the display unit 9, and update and display it on the character display for displaying the light emission intensity (15, 16). Then, the gain is set to the lower limit Gb (17), and the process returns to the main routine (FIG. 5) (proceeds to MDD).

FIG. 6b shows the contents of the “measurement of movement amount” (MDD).
When the process proceeds to “Measurement of movement amount” (MDD), the CPU 8 converts Ls = Sinθ and Lc = Cosθ into digital data and reads them (21, 22).
It is determined which of the equally divided quadrants No. 0 to 7 belongs, and data Dabc representing the determined quadrant No. i is determined (2
3). FIG. 4 shows the relationship between the quadrant No., the polarities of Ls = Sinθ and Lc = Cosθ, the magnitude relation of Ls = Sinθ and Lc = Cosθ, and the quadrant data Dabc determined by focusing on these.

That is, in the determination of the quadrant No. (23), when No. 0: Ls, Lc ≧ reference value (0), and | Ls | <| Lc |, Dabc is converted to data (000) indicating decimal 0. If No.1: Ls, Lc ≧ reference value (0) and | Ls | ≧ | Lc |, then Dabc is defined as data (001) indicating decimal 1 and No.2: Ls ≧ reference If the value (0), Lc ≧ reference value (0) and | Ls | ≧ | Lc |, then Dabc is defined as data (010) indicating a decimal number 2, and No. 3: Ls ≧ reference value (0) , Lc <reference value (0) and | Ls | <| Lc |, Dabc is defined as data (011) indicating a decimal number 3, and No. 4: Ls, Lc <reference value (0), and If | Ls | <| Lc |, then Dabc is defined as data (100) indicating decimal 0, and No.5: Ls, Lc <reference value (0), and | Ls | ≧ | Lc | If there is, set Dabc to data (101) indicating decimal number 5, and No. 6: Ls <reference value (0), Lc ≧ reference value (0) and | Ls | ≧ | Lc | Data indicating decimal 6 No. 7: Ls <reference value (0), Lc ≧ reference value (0), and | Ls | <| Lc |, where Dabc is a decimal number 7 (111). Set forth in

When the quadrant data Dabc is defined, Tanθt = | Ls | / | Lc | is calculated when Dabc is 0, 3, 4, or 7, corresponding to the contents of the data Dabc (detected quadrants). when the 1, 2, 5 or 6, Tanθct = | Lc | / | Ls | is calculated (25:25 _{0-25 7).}

Next, the CPU 8 inversely converts the calculated Tanθt or Tanθct into an angle value θt or θct (26). This content will be described later with reference to FIG. 6c. The angle θt or θct is in the range of 0 ° to 45 °. These angles are 2-byte data and are represented by decimal numbers 0 to 1024.

CPU8 then obtained angle value, Ls = sin [theta = 0 angle (0) angle value relative to the converted into (theta) (27:27 ₀ ~
27 ₇ ). The converted angle value (θ) is 2-byte data, 1
It is represented by a number from 0 to 8191 in base 0.

CPU8 then converted angle value (theta) i.e. the end value of the pitch, it was replaced with decimal values, written into the current value register Rda ₁ for storing fractional values calculated this time (8
1).

The CPU 8 then reads the polarity of Lc = Cosθ and Ls = Sin
From the absolute value of θ, the direction of these composite vectors (θ)
Are set before and after the timing (θ = 0 °) at which pitch count up / down is performed (see FIG. 2A and FIG.
(82, 83), and if it is outside the area, the count data of the counter 11 is written to the pitch movement amount register Rp (84), and the current value is written to the fractional value register Rd. The calculated fractional value Rda ₁ is written (85). And
Rp + Rd-Rdi is calculated and written to the movement amount register TR (86), and the value indicated by the data of the movement amount register TR is updated and displayed on the character display 9. This display value is
The movable slit plate 1 calculated based on the pitch movement amount counted by the counter 11 and the movement amount fractional value calculated by the CPU 8 after the reset signal rises from L indicating the reset to H indicating the measurement. (The integer 1 corresponds to the slit pitch).

Direction (θ) of the composite vector of Lc = Cosθ and Ls = Sinθ
Is in the set small area Ar before and after the timing (θ = 0 °) at which the pitch count up / down is performed, CP
U8 is the fractional value Rda ₂ calculated last time and the fractional value Rd calculated this time.
a ₁ is to check whether larger or not than 180 ° corresponding value Rda (4096) (88, 89), and whether across the 0 ° corresponding value Rda (0), if the crossing direction (the 3 is detected (88, 89; 88, 90), and when it crosses in the clockwise direction (FIG. 3), the content of the pitch movement count register CS is updated to one larger. (91), When crossing counterclockwise, pitch movement count register CS
Is updated to one less (92). When there is no crossing, such an increment or decrement of the register CS is not performed.

Next, the CPU 8 writes the data of the current value register Rda ₁ (fraction data calculated this time) to the previous value register Rda ₂ and stores the pitch movement amount register Rp in the pitch movement amount register Rp.
Write CS data (94). And the fractional value register Rd
The fractional value Rda ₁ calculated this time is written in (85). And Rp +
Rd-Rdi is calculated and written to the movement amount register TR (86), and the value indicated by the data of the movement amount register TR is updated and displayed on the character display 9. This display value indicates the pitch movement amount and fractional movement amount calculated by the CPU 8 since the reset signal rises from L indicating reset to H indicating measurement.

As described above, when the direction θ (fractional value of the moving amount) of the combined vector of Ls = Sinθ and Lc = Cosθ is in the small area Ar including the timing at which the hardware up / down counter 11 counts up / down. The CPU 8 determines the moving direction of the movable slit plate 1 based on the current fractional value Rda ₁ calculated by itself and the previous fractional value Rda ₂ and determines the position (fractional value 0) at which the pitch movement amount count / up / down is performed. Judgment is made as to whether or not the vehicle has crossed, and if it crosses a fractional value of 0 in the forward direction (clockwise in FIG. 3), the pitch movement count register CS is counted up by one. the movement amount count register CS 1 counts down, the movement amount based on CS and a fractional value Rda ₁ TR - displays this on the display 9 calculates the (= pitch movement amount CS + fraction value Rda ₁ initial value Rdi fractional value) I do.

Hardware up / down outside small area Ar
Since neither the counter 11 nor the pitch movement amount count register CS counts up / down, the data of both counters completely match. Here, since it is not necessary to determine whether the count up / down of the pitch movement amount count register CS is necessary, the count data of the up / down counter 11
Calculates Rp movement amount based on the fractional locations Rda ₁ to (pitch shift amount) and CPU8 are computed _{TR (= Rp + Rda 1 -Rdi} ), and displays it on the display 9.

Referring to FIG. 6c, the angle value θ of Tanθt or Tanθct
The contents of the inverse conversion (26) to t or θct will be described. The angle [Aθ: 0 (0 °) to 1024 (45
Tangent value Tan (Aθ) = R (0) to R (1024)
Are stored as data for angle determination. That is, a tangent function inverse conversion table in the range of 0 to 45 ° (0 to 1024) is prepared.

When proceeding to the inverse transformation (26), the CPU 8 first compares Av = Tanθt or Tanθct with the tangent value R (512) of the intermediate value 512 in the angle range (0 to 1024) (31), and then obtains Av <R (512). ), Then Av is compared with the tangent value R (256) of the angle 256 (32). Thus, for example, when Av = R (4), that is, when Av is the tangent of angle 4 in decimal notation, step 31-
After passing through 32-33-34-35-36-37-38-42-43, the tangent value Av
Angle Aθ is an angle 4, and determines (70 _4). As a result, the angle Aθ is obtained through ten comparison determination steps.
Is calculated.

As described above, the pitch movement amount is counted up / down only in the small region Ar, and is not counted up / down in a wide region outside the region Ar. In addition, when there is one pitch change in the information area Ar, CP
As U8 counts up / down the pitch movement amount,
Depending on the use of the measuring device, the hardware counter 11 can be omitted.

FIG. 7a shows the configuration of the second embodiment of the present invention. In this embodiment, the hardware counter 11 is omitted, and the comparator 6 and the direction detector 10 are also omitted. The variable gain amplifier 5y converts the amplified light receiving signal Ls = Sinθ + Vsmy and its reference potential (intermediate value of the fluctuation range of the light receiving signal) Vsmy into A / D
The variable gain amplifier 5x provides the first analog / digital conversion input terminal and the reference potential input terminal of the converter 7 with the amplified light receiving signal Lc = Cos θ + Vsmx and the reference potential (intermediate value of the fluctuation range of the light receiving signal) Vsmx To the second analog / digital conversion input terminal and the reference voltage input terminal of the A / D converter 7.

The A / D converter 7 converts the levels of the signal potentials Ls and Lc with respect to the reference potentials Vsmy and Vsmx into digital data.

In the CPU 8, a movement amount detection program similar to that of the above-described first embodiment (FIG. 1) is incorporated. FIG. 7b shows only the portions of the movement amount detection program of the second embodiment that are different from those of the first embodiment. This corresponds to subroutine 81 to step 94 in FIG. 6b.
Other parts are the same as those of the first embodiment. 7b
Referring to the figure, in this second embodiment, the CPU 8
Is determined to be outside the range, the pitch movement amount register CS
Is written into the register Rp (84). That is, since there is no up / down counter 11, the pitch movement amount register
Write the CS data directly to the register Rp. Since the data of the pitch shift register CS is written into the register Rp even when the pitch shift amount is within the range of the small area Ar, in the second embodiment, the pitch shift amount (in the entire range of the direction θ of the combined vector of Ls and Lc). As the integer, a value counted by the CPU 8 is used. However, the count-up / down of the pitch movement amount (integer value) may be performed only in the small range Ar, so that the necessity of the count-up / down (88 to 90) is determined only in the small range Ar. Do not execute within the range outside Ar.

〔The invention's effect〕

As described above, in one aspect of the present invention, the trigonometric function value calculation means (8) calculates the ratio between the first and second digital data, and the inverse conversion means (8) calculates the ratio between the first and second digital data. 2
(Θ) represented by the correlation of the levels of the electrical signals
Since the data is converted into the corresponding data (Rd), even if the levels of the first and second electric signals generated by the electric signal generators (1 to 4x, 4y) both change in the same direction, the ratio substantially fluctuates. No change in data (Rd). Therefore, the fractional value (R
d) The measurement becomes accurate.

If the level of the first and second electric signals fluctuates greatly, an error in the conversion into digital data increases due to the resolution of the A / D conversion, which also affects the calculation ratio. Adjusting means (8)
Since the gains of the first and second amplifying means (5x, 5y) are adjusted so that the root mean square of the second digital data becomes a set value, conversion into digital data by A / D conversion resolution is performed. Is small, the ratio is calculated with stable and high accuracy, and the fractional value (Rd) is accurately measured.

In addition, the counting means (8) determines the direction (clockwise / counterclockwise) of the movement of the movement amount measurement target and the value corresponding to the predetermined angle (0 °) based on the time-series transition of the angle-corresponding data (Rd). 0) The passage is detected, and when the passage of the value corresponding to the predetermined angle is in one direction (clockwise), the pitch movement amount information (CS) is updated to a value larger by one pitch, and the other direction (counterclockwise).
In the case of, since the value is updated to a value smaller by one pitch, the switching of the angle-corresponding data (Rd) and the pitch movement amount information (C
Switching of S) is synchronized, and this pitch movement information (CS)
The measured value (CS + Rd) does not cause an instantaneous change of one pitch at the time of switching, and the measured value continuously changes with the continuous movement of the movement amount measurement object.

In the other sun of the present invention, in a wide range outside the immediate area (Ar) including the timing at which the up / down counter (11) counts up / down, the movement amount information calculating means (8) increases the sun. / From the count data (Rp) of the down counter (11) and the data corresponding to the angle (Rd),
Since information (TR) including the pitch movement amount (Rp) and the movement amount within one pitch (Rd) is generated, data corresponding to the angle (Rd)
Since the pitch movement amount calculation processing such as the determination of the necessity of counting up / down of the pitch movement amount based on the above is unnecessary, and the counting by the up / down counter (11) is fast, the movement amount with respect to the actual movement amount is obtained. High tracking accuracy of measured values. In the immediate area (Ar) including the timing at which the up / down counter (11) counts up / down, the counting means (8) determines the direction of movement of the movement amount measurement target from the transition of the data (Rd) corresponding to the angle. , A predetermined angle (0
゜) The passage of the corresponding value (0) is detected, and when the passage of the predetermined angle corresponding value is in one direction (clockwise), pitch movement amount information (C
S) is updated to a value larger by one pitch, and in the other direction (counterclockwise), it is updated to a smaller value by one pitch. Information (TR) including the pitch movement amount (CS) and the movement amount within one pitch (Rd) from the data (Rd) corresponding to the angle (CS) and the angle.
Is generated, the switching of the pitch movement amount information (CS) and the change (coordination) of the movement amount within one pitch (Rd) are coordinated, and a measurement error of approximately one pitch does not occur between the two.
The calculation of the above-mentioned pitch movement amount information (CS) by the counting means (8) requires a relatively long time, but since the region (Ar) in which this is performed is a very narrow range, the time series average The follow-up performance does not significantly decrease.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention. FIG. 2a is a time chart showing the levels of the signals output by the variable gain amplifiers 5y and 5x shown in FIG. FIG. 2b is a time chart showing the absolute value level of only the variation of the signals output by the amplifiers 5y and 5x shown in FIG. FIG. 3 is a plan view showing the combined vector direction θ of the variation of the output signals Ls and Lc of the variable gain amplifiers 5y and 5x, and quadrant divisions obtained by dividing the entire range of the direction θ from 0 to 360 ° into eight equal parts. It is. FIG. 4 shows the quadrant to which the direction θ belongs and the amplifier shown in FIG.
FIG. 3 is a plan view showing a relationship between signal levels Ls and Lc of 5y and 5x and correlations, and data generated by the CPU 8 shown in FIG. 1 in each quadrant. FIG. 5, FIG. 6a, FIG. 6b and FIG. 6c are shown in FIG.
6 is a flowchart showing the contents of a calculation process of the CPU 8. FIG. 7a is a block diagram showing a second embodiment of the present invention. FIG. 7b is a flowchart showing the contents of the arithmetic processing of the CPU 8 shown in FIG. 7a, and shows only the parts different from the arithmetic processing of the CPU 8 shown in FIG. 1: movable slit plate, 2: fixed slit plate 3: light source, 4x, 4y: photo sensor (1 to 4x, 4y: electric signal generator) 5x, 5y: variable gain amplifier (first and second amplification means) 6: Comparator (binarization means), 7: A / D converter (A / D conversion means) 8: Microprocessor (signal level adjustment means, trigonometric function value calculation means, inverse conversion means, counting means, movement amount information Calculation means) 9: Display unit, 10: Direction detector (direction detection means) 11: Up / down counter (up / down counter) HS: Key switch

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kazuo Kato 79-2 Kamoshida, Midori-ku, Yokohama-shi, Kanagawa Prefecture, within System Uniques Co., Ltd. (56) References JP-A-55-54406 (JP, A) Showa 55-27962 (JP, A) Japanese Patent Publication Sho 62-57930 (JP, B2)

Claims (3)

(57) [Claims] 1. A first and a second electric device, which are coupled to a movement amount measurement object and have one cycle with respect to a movement such as a linear movement or a rotation movement of a predetermined unit, and which are out of phase with each other by two sets of 90 °. An electric signal generator for generating a signal; first and second amplifying means for amplifying the first and second electric signals, respectively; first and second amplifying means for increasing the level of the signal amplified by the first and second amplifying means, respectively; A / D to convert to second digital data
Conversion means; signal level adjusting means for adjusting the gains of the first and second amplifying means so that the root mean square of the first and second digital data becomes a set value; A trigonometric function value calculating means for calculating the ratio; an inverse converting means for converting the ratio calculated by the trigonometric function value calculating means into angle-corresponding data represented by a correlation between the levels of the first and second electric signals; From the time-series transition of the data, the direction of movement of the movement amount measurement target and the passage of a predetermined angle corresponding value are detected,
At the time of passing the predetermined angle corresponding value, when the detected moving direction is one direction, the pitch moving amount information is updated to a value larger by one pitch value, and when the detected moving direction is the other direction, the pitch moving amount information is updated to a value smaller by one pitch value. A movement amount information calculating means for generating information including a pitch movement amount and a movement amount within one pitch from the pitch movement amount information and data corresponding to an angle; 2. A method according to claim 1, wherein said first and second electric units are coupled to a movement amount measurement object and have a period of 90.degree. With respect to a predetermined unit of movement such as linear movement and rotation movement. An electric signal generator for generating a signal; binarizing means for binarizing the first and second electric signals into first and second pulse signals; the movement amount measurement object from the first and second pulse signals Direction detecting means for generating a direction signal representing the direction of movement of the first and second pulse signals when the direction signal is in one direction; and an up / down counter for counting down when the direction signal is the other. First and second amplifying means for amplifying the first and second electric signals; A / D for converting the level of the signal amplified by the first and second amplifying means into first and second digital data, respectively;
Conversion means; trigonometric function value calculation means for calculating a ratio of the first and second digital data; inverse conversion means for converting the ratio calculated by the trigonometric function value calculation means into data corresponding to an angle; the up / down counter counts In the immediate area including the timing of up / down, the direction of movement of the movement amount measurement object and the passage of a predetermined angle corresponding value are detected from the time series transition of the angle corresponding data, and the time point of passing the predetermined angle corresponding value is detected. A counting means for updating the pitch movement amount information to a value larger by one pitch when the detected movement direction is one direction, and updating the pitch movement amount information to a value smaller by one pitch when the direction is local; In the immediate region, information including the pitch movement amount and the movement amount within one pitch is generated from the pitch movement amount information and the data corresponding to the angle. A movement amount information calculating means for generating information including a pitch movement amount and a movement amount within one pitch from count data of an up / down counter and the data corresponding to the angle; 3. The trigonometric function value calculating means compares the first and second digital data and determines that the angle represented by the data is No. 0: 0 ° or more and less than 45 °, No. 1: 45 ° or more. No. 2: 90 to 135 mm, No. 3: 135 to 180 mm, No. 4: 180 to 225 mm, No. 5: 225 to 270 mm, No. 6: 270 mm or more and less than 315 mm, No. 7: 315 mm or more and less than 360 mm, and when No. 3, 4 or 7 is detected, the first and second values correspond to the tangent values. Calculating the ratio of the absolute values of the digital data and calculating the ratio of the absolute values of the first and second digital data corresponding to the reciprocal of the tangent value when No. 1, 2, 5, or 6 is detected; The moving amount measuring device according to claim 1 or 2.