JPS6038617A - Photoelectric type angle measuring apparatus - Google Patents

Abstract

PURPOSE:To elevate the response of the titled apparatus by using a photoelectric means for generating a signal. CONSTITUTION:LEDs 110 and 111 are controlled in the lighting by a sine wave and a cosine wave with a modulated pulse width respectively and the emissions of the LEDs are changed according to the angle of intersection between a polarizer disc 105 of a polarizer rotor 108 and transmission axes of respective polarizer plates 116 and 117 and applied to phototransistors PTR 112 and 113. Therefore, as the rotor 108 rotates integral with the turning of a detection shaft 103, a voltage signal is generated in each of the PTRs which varies in the state of sine wave and cosine wave in proportion to the doubling of the angle theta of rotation of the shaft 103. The signal generated and the drive signal from an ROM123 are computed 130 and a phase signal is extracted via an LPF140.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an angle measuring device in which the signal generating means of a resolver is photoelectric.

Resolvers are widely used as angle or position detectors for robot I-, No. 2 machine tools, etc.

The reason for this is that speed information and angle information can be obtained with a single device, and the structure is relatively simple and failures are rare.

Additionally, integrated circuit signal converters (e.g.

This is because a high-resolution angular pulse can be easily obtained in combination with Analog Devices' IRI) 01730).

The resolver will be briefly explained below.

In FIG. 1 showing the principle, two coils 2 and 3 are wound around a stator 1 in a perpendicular state.

Inside the stator 1 is a rotatable rotor 4,
A coil 5 is wound around it.

When using the coil 5 of the rotor 4, the voltage generated in the coils 2 and 3 of the stator 1 can be used, and vice versa. May be used.

That is, in the former case, as shown in FIG. 2, a voltage Vc of the following formula is applied to the coil 5 where: Vc = Vl s in ωt 1 where 1: amplitude, ω: excitation angular velocity. As a result, the magnetic flux interlinking with the coils 2 and 3 changes in accordance with the rotation angle θ of the rotor 4.

As a result, voltages Va and Vb generated in coils 2 and 3
The amplitude of changes depending on the rotation angle θ. in the end.

The result is that the rotation angle θ is converted into an amplitude signal as shown in the following equation.

Here, Kl: proportional coefficient (constant) Next, the latter is 90% for the coil 2°3 as shown in Figure 3.
When voltages Va and Vb with a degree phase difference are applied, the magnetic flux interlinking with the coil 5 among the respective magnetic fluxes changes corresponding to the rotation angle θ of the rotor 4,
As a result, the phase of the voltage VC generated by the coil 5 changes in a quadratic manner corresponding to the rotation angle θ. As a result, the two rotation angles θ are converted into phase signals as shown in the following equation.

Vc = K2V2 cos ωt sinθ+2V
2 s in ωt cos θ= to 3V2 s in (
When ω is 10 θ) or more, the resolver converts the signal into an angle signal whose amplitude or phase changes depending on the rotation angle θ of the rotor 4 and extracts it.

Hereinafter, to simply determine the angle θ, either measure Va and Vb of the above equation 0 with a voltmeter, or measure the voltage Vc of the above equation 0.
The phase difference θ between and the excitation signal Va shown in equation 0 is measured using a phase difference meter.

In addition, for example, the rotation angle θ used for the feedback signal of the servo system
In order to obtain the pulse train signal and angular velocity signal dθ/dt corresponding to , it is sufficient to combine the amplitude signal of the above-mentioned 0 type with a converter such as the above-mentioned H 01730 developed for the conversion.

An example of this type of converter will be briefly described below.

In FIG. 4, 6 and 7 are the output terminals of the output voltages Va and vb of the coils 2 and 3 of the resolver, respectively, which are connected to one input terminal of the corresponding cosine multiplier 11° and sine multiplier 12, respectively. and cosine multiplier 11
．． The other input terminal for angle data of the sine multiplier 12 is connected to the counted value output terminal of a reversible counter 13 (described later), and the cosine multiplier 11. The output end of the sine multiplier 12 is connected to the positive and negative input ends of the deviation amplifier 14, and the output end of the deviation amplifier 14 is connected to the input end of the phase detection circuit 15.
The detection command input terminal is connected to the output terminal 8 of a rectangular wave shaping circuit (not shown) for the excitation signal of the resolver, and the detection signal output terminal of the 1-phase detection circuit 15 is connected to the low-pass filter 21 of the addition/subtraction pulse generator 20. The output end of the low-pass filter 21 is connected to the input end of the absolute value circuit 22, and the output end of the absolute value circuit 22 is connected to the input end of the voltage controlled oscillator 23. The output end is the first. It is connected to one input terminal of the second gate circuit 24, 25, and the other input terminal of the first gate circuit 24 is connected to the polar signal output terminal of the 1-phase detection circuit 15 and the inverter 26.
The other input terminal of the second gate circuit 25 is directly connected to the polarity signal output terminal, and the first . The output terminal of the second gate circuit 24.25 is an external terminal 27.2.
8, and the reversible counter I3.
addition.

Each is connected to the reduction input terminal.

FIG. 5 is a waveform diagram of the signal corresponding to the number indicated in a circle on the signal line in FIG. 4. Hereinafter, with reference to FIGS. The operation of the above converter will be explained by taking as an example the case where the angle is changed from 30 degrees to 45 degrees.

Assuming that the second rotation angle remains at 30 degrees and does not move,
The voltage Va taken out from the output ends 6 and 7 of the coils 2 and 3,
vb is obtained from equation (2). Also, in this state, there is no input pulse to the reversible counter 13 (
In other words, there is no generation of incremental signals).

The count value of the reversible counter 13 corresponds to 30 degrees. That is, cosine multiplier 11. Sine multiplier 12
In, Va − and cos 30 , respectively.

A multiplication of Vb-sin 30 is performed, and in the end, the result of the two-car multiplication is the same (I3KM/4) sin ωt, which is the result.

The output of the deviation amplifier 14 becomes O, and the 9-phase detection circuit 15,
Both input and output of the additive pulse generator 20 are O. Next, when the resolver rotor 4 starts rotating from 30 degrees,
The output voltage Va of the coil 2 increases, and the output voltage Vb of the coil 3 decreases. As a result, the output of cosine multiplier 11 increases and the output of sine multiplier 12 decreases. As a result, the deviation amplifier 14 outputs a sine wave of angular velocity ω having an amplitude corresponding to the difference between the two outputs.

In the phase detection circuit 15, 0 to 180 of the sine wave
The output in the phase range of degrees is detected, it is leveled through a low-pass filter 21, and then through an absolute value circuit 22 (in this case, the detection output is positive, and the output of the low-pass filter 21 is simply (only passes through the absolute value circuit 22)
It is sent to a voltage controlled oscillator 23 which generates pulses at a frequency proportional to its input. At this time, the detection signal of the phase detection circuit 15 is positive, and as a result, no polarity signal is sent out, only the first gate circuit 24 is conductive, and the output pulse of the voltage controlled oscillator 23 is sent to the external terminal 27. At the same time as being output, the signal is introduced into the addition input terminal of the reversible counter 13. As a result, the count value of the reversible counter 13 increases,
When the count value becomes tt of the above value, Va and Vc become 2.
Due to the multiplication, the output of the cosine multiplier 11 is decreased from the above, and the output of the sine multiplier 12 is increased from the above, and as a result, the output of the deviation amplifier 14 is reduced, and the output of the voltage controlled oscillator 23 is accordingly reduced as before. A pulse is sent out, and the count value of the reversible counter 13 increases.

That is cosine multiplier 11. As a result of being applied to the sine multiplier 12, the deviation between both outputs is further reduced.

The above-mentioned Rokuma coincides with the motion when rotating by a minute angle, and the outputs of the cosine multiplier 11 and the sine multiplier (KIV+
cosφsinθ)sinωt and (K+V1 sin
Loop control is performed so that φ cos θ) sin ωt match.

It becomes an incremental signal store corresponding to the increment of .

The count value of the reversible counter 13 that adds or subtracts this incremental signal directly corresponds to the rotational angle θ of the rotor 4, and the output voltage of the low-pass filter 21 is the rotational angular velocity dθ/of the rotor 4. It corresponds to dt.

By the way, the above resolver uses electromagnetic induction to generate signals, and therefore, if the excitation voltage is high, the secondary voltage waveform will be distorted.

This will result in a significant decrease in accuracy. Also.

It is inevitable that the penetrating moment of the entire rotor will be relatively large due to the rotor 4, the coil 5[deg.] wound around it, the rotating transformer for supplying excitation signals, etc. This is a problem especially when the moment of inertia of the object to be detected is small.

This causes a significant response delay. Also.

Although the structure is relatively simple, in actual manufacture, strict precision is required in the winding position of the coil in order to maintain uniformity of magnetic flux distribution, which inevitably leads to a problem of high cost.

An object of the present invention is to provide an angle measuring device that always has high responsiveness. More specifically, the upper limit of the frequency of the signal carrier wave is high, and there is no signal exchange with the rotor.

The object of the present invention is to provide an angle measuring device that does not require parts for transmitting and receiving signals, has a small moment of inertia of the rotor itself, and has high responsiveness.

Another object of the present invention is to provide an angle measuring device that is easy to manufacture and inexpensive despite having high responsiveness.

The present invention uses photoelectric means as a signal generation means, and a plurality of light sources whose light emission amounts are controlled by a sine wave drive signal having the same phase or a phase of 90 degrees with each other and a plurality or a common light receiving element are arranged in a rotor. and photoelectric conversion means which were placed opposite each other.

Provided for the photoelectric conversion means and rotor.

The rotation angle of the rotor is controlled by a light amount changing means that changes the amount of transmitted light between the light source and the light receiving element in the form of a sine wave with a phase of 90 degrees relative to each other, and a signal converting means that converts the light receiving element output of the photoelectric conversion means into an angle signal. An amplitude signal having an amplitude corresponding to the rotation angle of the rotor or a phase signal having a phase corresponding to the rotation angle of the rotor can be obtained.

First, the principle and outline of the present invention will be explained with reference to mathematical formulas. Two or four light sources are placed on one side of the rotor, and two or four light sources are placed opposite the light source on the other side.
Alternatively, a shared light-receiving element is arranged facing all of the light sources.

Then, each light source turns on its light emitting section in response to a sine wave-like drive signal, and changes the amount of light emitted in a sine wave form. Here, when extracting an amplitude signal corresponding to the rotor rotation angle, the phase of the drive signal of each light source is set to the same phase, and when extracting a phase signal corresponding to the rotor rotation angle, the phase of the drive signal of each light source is set to the same phase. They will be shifted by 90 degrees from each other.

That is, the angular velocity of the drive signal is ω, and each light source la, lb
, IC, td (Ia, lb if there are two light sources)
Let ea-ed be the amount of light emitted by (only), and let A be the minimum value of the amount of light emitted and the maximum value of O2.

The amounts of light emitted from ea to ed are when driven by in-phase drive signals.

e=ea=eb-ec=ed=(A/2)(Sinωt
+1) (1), when driven by drive signals whose phases are shifted by 90 degrees.

shall be.

Now, in the second order, this amount of light emission is determined by each of the opposing light receiving elements 2a,
2b, 2c, 2d or shared light receiving element 2a+2
b+20+2d (2a if there are two light sources,
2b or 2a-1-2b), but a light amount changing means provided for the rotor and the photoelectric conversion means is interposed in this optical path, so that each The amounts of emitted light are shifted in phase by 90 degrees from each other, and are changed in a sine wave shape corresponding to the rotation angle of the rotor, and then introduced into the light receiving elements 23 to 2d.

Note that when a shared light receiving element is used instead of the light receiving elements 23 to 2d, the sum of the amounts of light introduced to each of the light receiving elements 2a to 2d is introduced, and when two light receiving elements are used,
Since two of the above light receiving elements will be used,
In the following description, a case will be described in which there are four light receiving elements 2a to 2d.

Now, as the above-mentioned light amount changing means, there are those that use a pair of polarizer plates, those that use a transparent aperture rotor formed eccentrically with respect to the rotor, etc. The rate of change in light amount due to each of these methods will be explained below. .

That is, the ratio between the input light amount and the output light amount of the light amount changing means will be explained with reference to mathematical expressions.

First, there is a light amount changing means using a pair of polarizer plates.

Let α be the intersection angle of the transmission axes of a pair of polarizer plates.

This method utilizes the fact that the amount of light Iα transmitted through it changes as shown in the following equation in response to α (Malus's law).

I===Io ((Ho −H2O)CO82α+
I(90) (3) = IO(K4 CO82α+5
) here 1. ll; Amount of transmitted light when the intersection angle of the transmission axes is α IO = Amount of transmitted light before inserting the polarizer plate Ho Bi-parallel (the transmission axes of the two polarizer plates are parallel) Transmittance H,, o: Orthogonal (the transmission axes of the two polarizer plates are orthogonal) Transmittance α: 4 at the intersection angle of the transmission axes: (1/2XHo Hgo) Ks: (1/2) ()IO+H90) In other words, the rotor has polarized light The daughter plates are fixed integrally, and polarizer plates are also arranged in the path of each light source and light receiving element, and the transmission axes of the polarizer plates are shifted from each other by 45 degrees. Note that, contrary to the above, there are 45
Even if a donut-shaped polarizer disk whose transmission axis is shifted is integrally fixed and the transmission axis of the polarizer plate interposed between the light source and the light receiving element is the same, it is the same thing. As a result, the ratio of the input light amount to the output light amount of a pair of polarizer plates whose transmission axes are shifted by 45 degrees from each other.

That is, the transmittance of the pair of polarizer plates βa, A, βC2β
d (if there are two light sources, only βa+A) is.

As a result, the transmittances βa to βd change in the form of a sine wave whose phase is shifted by 90 degrees in response to the rotation angle θ. However, this transmittance is proportional to the sine function value of twice the rotation angle θ, and therefore, during one rotation of the rotor,
A sinusoidal transmittance change pattern occurs twice.

The overlapping state of the translucent mill and the X and Y axes drawn on the plane facing the can be changed. That is,
On the above plane, the origin is the same as the center of the rotor, and the Y-axis and Y-axis are drawn, and with the origin as the center, the negative Y-axis, negative Y-axis, positive Y-axis, and positive Y-axis, respectively. Considering s Ad on the line of overlap with the eccentric translucent mill, let's now set the rotational position of the rotor where the center of the eccentric translucent mill is on the left side of the center of the rotor as a reference, and rotate the rotor counterclockwise. This method utilizes the fact that when the rotation angle in the direction is θ, the line segments change in a substantially sine wave shape with a phase shift of 90 degrees like quadratic.

Here, L: Radius of the eccentric light-transmitting circle R: Amount of eccentricity Therefore, the photoelectric conversion means consisting of a light source and a light receiving element placed between the rotor is also a part of the light amount changing means, and the light emitting surface and light receiving surface thereof are One or both of the positive and negative X's are formed in a rectangular shape.

placed on the Y axis.

Note that instead of forming the projection and light receiving surfaces into rectangular shapes.

The same thing can be done even if a mask having a rectangular slit is placed in front of the mask.

Now, the ratio of the input light amount to the output light amount in this light amount changing means, that is, the transmittance is the ratio of the line segment ta-gradient determined by the rotation angle with respect to the maximum superimposed line segment (R + L), and now the transmittance is expressed as γ2 ~γd, they are expressed by the following equation.

The above is the light amount changing means, and the amount of light emitted from the light source to the light receiving element reaches the light receiving element after being multiplied by the transmittance shown in equation (4) or equation (6) above.

Below, we will explain the case where the emitted light amount is in the same phase for the purpose of generating an amplitude signal, that is, the case where one emitted light amount is given by e in equation (1) above, and the case where the emitted light amount is 90 degrees phased for the purpose of generating a two-phase signal. The amount of light received by each of the light-receiving elements 2a to 2d and the voltage generated thereby will be explained using mathematical formulas, dividing into the case of ea-ed in the above formula (2).

First, in one in which the light amount changing means is a pair of polarizer plates.

The amount of light received by each light receiving element when the amount of emitted light is in the same phase is fa~
fd, they become as follows.

As a result, the generated voltage ga''gd of each light receiving element is.

It corresponds to that amount of light, and now let M be the light amount-voltage conversion coefficient, K6 = AK4M/2, K7
If we set =AK5M/2, the 2 generated voltage will be as follows.

Similarly, when one light emission amount is set to a 90 degree phase, the amount of light received by each light receiving element is set as fa' to fd', which are as follows.

Therefore, the second generated voltages ga' to gd/ are as follows.

Next, the light amount changing means is an eccentric light-transmitting internal rotor.

The amount of light received by each light receiving element when the amount of emitted light is in the same phase is
hd, it will be as follows.

hd=γde As a result, the generated voltage 1a=id of each light receiving element is.

It corresponds to the amount of light, and now let the light amount-voltage coefficient be M, then 8=M/2 (R+L), Ks
=AM/2 (R+L), the generated voltage of 2 is as follows.

Similarly, if the amounts of light received by each light-receiving element are set as ha' to hd' when the two amounts of emitted light are set at 90 degrees phase, they are as follows.

Therefore, the two generated voltages la' to summer l are as follows.

As described above, by coupling the photoelectric conversion means and the light amount changing means, the voltage signal shown in equation (8) 110 < 12 < 14, which has information on the rotation angle θ of the rotor, is obtained in each of the light receiving elements 2a to 2d. .

Next, send this voltage signal to a signal converter.

Conversion is performed into an angle signal having an amplitude or phase corresponding to the rotation angle θ.

In the signal converter C1, first, the output of the light-receiving element is introduced into a bypass filter, and low-frequency components, which are frequency components that change depending on the rotational angular velocity of the rotor, and DC components are blocked. As a result, in the case where the light amount changing means described above is a pair of polarizer plates.

First, when the two amounts of light emission are in phase, only the next component Ja-Jd is extracted from the output of equation (8).

Similarly, only the following components ja' to "d' are extracted from the output of the C0 equation when the two light emission amounts have a 90 degree phase.

Further, in the case where the light amount changing means is an eccentric light-transmitting inner rotor.

First, when the two light emission quantities are in phase, only the next component ma-md is extracted from the output of equation 113.

Similarly, only the following components ma' to l1ld' are extracted from the output of formula 04 when the amount of light emission is at a 90 degree phase.

Next, in the signal converter, the output of this bypass filter is introduced into an addition/subtraction calculator to perform a predetermined addition/subtraction calculation.

In other words, in order to form an amplitude signal corresponding to the two rotation angle θ, the extracted components shown by the a9 or α7 formula are subtracted from each other as shown below, so that the amplitude changes in a sine wave shape and a cosine wave shape, respectively. 2 outputs nI+n
2 or n1' + n2''.

That is, for the extracted component J a '' J d of the above formula 00.

Similarly, the extracted components ma to Ind of the α7 formula are subtracted, thereby forming an amplitude signal. Next, the phase signal corresponding to the rotation angle θ of the rotor is the above-mentioned σ
By adding the extracted components represented by the formula 0 or 08 as shown below, the phase is converted into a signal P or P' corresponding to the rotation angle θ.

That is, the same applies to the extracted components Ja' to Jd/ of the α0 formula, and the same applies to the extracted components ma' to mdl of the 08 formula.

p'=m3'4mb'-4-In,'-1-m(1'=
2Ks (cos0sinωt-5inθcosωt)
-zKs sin (ωt-θ) -ea is calculated, thereby forming a phase signal.

Now, in the explanation of 2 and above, the number of light receiving elements is assumed to be four.

This is a case where an amplitude signal and one phase signal are obtained by adding and subtracting the respective outputs. By the way, in the case where the light amount changing means is a pair of polarizer plates, as shown in the above equations 0θ and 00, the outputs Ja' to jd' of the bypass filter have amplitudes that are unrelated to the rotation angle θ. sinω with constant amplitude
There is a component of t or cos ω1, and this component can be formed simply by amplifying the drive signal for the light source described above to a predetermined amplitude via an amplifier. Therefore, the same effect can be obtained by using two light-receiving elements, adding them and a signal obtained by amplifying the drive signal to a predetermined amplitude as described above to the addition/subtraction calculator, and calculating the difference between the two signals.

In addition, when forming a two-phase signal, the outputs of each light receiving element are added, and by using a shared light receiving element that faces all of the light sources, the light receiving element itself may have the function of adding the amount of light.

Furthermore, even if the order of filtering of the light receiving element output and addition/subtraction operations is reversed, the result is the same.

The above is an explanation of the principle and outline of the present invention.

Next, two preferred embodiments of the present invention will be described in detail.

In FIG. 6 and FIG. 7 showing a cross section in the AA direction, a bearing 102 is provided on the front cover 101 of the cylindrical housing 100.
An angle detection shaft 103 is rotatably supported through the housing 100, and a polarizer disc 105 is attached to the rear end 104 of the detection shaft 103, which penetrates into the housing 100.
A polarizer roller 108 which is sandwiched and bonded between the rollers 7 and 7 is integrally fixed. On the front cover 101 of the housing 100 located on the left side of the roller 108, there are two light emitting diodes 110 and 111 (111 in the two figures is not shown because it is located on the rear side of the detection axis 103). is fixed.

The housing 100 is located on the right side with the polarizer roller 108 in between.
The rear bottom plate 109 includes the light emitting diode 110,
A phototransistor 112. is located opposite the phototransistor 111.
113 is fixed, and its phototransistor 112 .
113 holding case 114. On the front surface of 115, polarizer plates 116 and 11 are provided with transmission axes shifted by 45 degrees from each other.
7 is fixed.

FIG. 8 shows the light emitting diode 110. A light source 120 including a phototransistor 112 . 113 is a block diagram of an addition/subtraction calculator 130 and a filter 140 forming a signal converter for the output voltage of No. 113. FIG. In the figure, the light source 12
The configuration of clock pulse oscillator 121 . A counter 122 to which the output is introduced, a read-only type that outputs a predetermined H'' or II I, 71 signal written in advance at each address and written in advance to each address, in which the counted value output of the counter 122 is introduced as an address designation signal. Memory (ROM) 123
, the read-only memory's 90 degree phase outputs, which will be described later, are respectively introduced, and the corresponding light emitting diodes 1.10. Drive circuit 124゜1 that lights up 111
It consists of 25. And the read-only memo 1J
123, as shown in Figure 9, (Al/2)(s
inωt-)-1) waveform [where A-1/2 is the amplitude], a triangular wave with a minute period is superimposed, and the intersecting period is "I Hll", and the other is ILLI+. Pulse width modulation. A signal is written with that time as an address, and a pulse width modulation signal whose phase is shifted by 90 degrees is also written.Therefore, from the read-only memory 123, the signal corresponds to a sine wave and a cosine wave of angular velocity ω. The pulse width modulated signals are sent to the drive circuits 124 and 124, respectively.
125 and two light emitting diodes 110. 111 is
The amounts of light shown as ea and eb in equation (2) above will be emitted, respectively. Next, the signal converter consists of an addition/subtraction calculator 130 and a bypass filter 140. In addition.

Here, a signal converter for extracting a phase signal is illustrated. Now, the operational amplifier 135 of the addition/subtraction calculator 130 receives the pulse-width modulated sine wave and cosine wave output from the read-only memory 123 through respective inverters 13 .

132 and then input resistor 133. 134 multiplies the voltage by a predetermined ratio and adds the output voltage of the phototransistors 112 and 113. The output of the operational amplifier 135 is sent to the output terminal 141 via the No. 1 pass filter 140.

In the above, the nine light emitting diodes 110° and 111 each have a pulse width modulated sine wave.

The lighting is controlled by a cosine wave, and as a result, two light emitting diodes 110. 111 each emits light amount of ear 61) shown in equation (2) above. and.

Phototransistor 112 of that amount of light. The amount of transmission to the polarizer 113 is changed depending on the angle of intersection of the transmission axes of the polarizer disk 105 of the polarizer rotor 108 and the respective polarizer plates 116 and 117. Therefore, when the rotor 108 rotates integrally with the rotation of the detection shaft 103, each phototransistor 112. At 113, a voltage signal ga'+gb' shown in the above formula 00 is generated which changes in a sine shape and a cosine shape in proportion to the double angle of the rotation angle θ of the detection shaft 103, and the voltage signal is sent to the addition/subtraction calculator 130. Added as a sum signal. At the same time, the read-only memory 1
The sine wave and cosine wave drive signals generated by inverter 131 . After being inverted via 132,
The amplitude is made to match 7 shown in the above formula by resistors 133 and 134, and is applied to the addition/subtraction calculator 130 as a subtraction signal. Therefore, the output q of the addition/subtraction calculator 130 is.

q = ga' + gb' - 7 sin ωt - 7 co
sωt= K6 CO52θsinωt- to 6sin2
θcosω to 6 cos 2θ− to 6sin2θ
It becomes C3. Next, this output q is passed through bypass filter 1
40, the low frequency components therein, that is, the third and fourth terms, are
The component of the term Q
A phase signal whose phase is proportional to a multiple of the rotation angle θ of the detection shaft 103 is sent out as shown in the tJ equation. In addition, although the above-mentioned example illustrated the case where filtering is performed after addition and subtraction operations, it is the same even if the order is reversed. Further, in the above embodiment, the light emitting diode 1 is directly inside the housing 100.
110, 111 and phototransistors 112 and 113 are shown as an example, but in order to further reduce the size of the two mechanical parts, these are provided externally.

Transmission and reception of light between them may be performed using an optical fiber. Further, in the above embodiment, the case where two sets of light sources and light receiving elements are used is illustrated, but the inverter 131. 132 outputs separately provided. In addition to each of the fourth light emitting diode drive circuits.

And the third one which is opposite to it. In front of the fourth phototransistor, there is a third phototransistor whose transmission axis is parallel to each other by 45 degrees. A fourth polarizer plate is provided.

Even when the outputs of the first to fourth phototransistors are added, the same result is obtained as shown in the above-mentioned QtJ equation.

Further, in the above embodiment, the polarizer plate 105 on the rotor 108 side
have a single transmission axis, and polarizer plates 116 . 117, the transmission axes of the rotor 108' are shifted by 45 degrees from each other, but as shown in FIG. 10 and FIG. 11 showing a cross-section in the C-C direction, The donut-shaped first.
a second polarizer disc 105'';

105' is fixed, and two light receiving elements 112 and 113 are attached.
The same effect can be achieved even if a polarizer plate 116' having a single transmission axis is disposed in front of the lens.

The above is an embodiment in which the light amount changing means is a pair of polarizer plates.

Next, the light amount changing means is an eccentric circular rotor and a light source.

Another embodiment of the present invention will be described in detail, in which one or both of the light-receiving elements have a rectangular facing surface as a photoelectric conversion means.

In FIG. 12 and FIG. 13 showing a cross section in the B-B direction, a bearing 10 is mounted on the front cover 101 of the cylindrical housing 100.
2, the angle detection shaft 103 is rotatably supported, and the rear end 104 of the detection shaft 103 penetrates into the housing 100.
An eccentric transparent circular roller 208 is integrally fixed. Eccentric transparent circular roller 20B.

Translucent disk 205 is replaced by transparent thin glass disk 106. 107
The light-transmitting disk 2
05 is a light-shielding disk 205', which is a circle 205'' with a radius centered on a point eccentric by a distance from the center of the light-transmitting circular roller.
It was punched out from. The eccentric transmission circular rotor 20
Inside the front cover 101 located on the left side of 8, light emitting diodes 110', to' are arranged radially at intervals of 90 degrees.
, 210.211 (However.

111', 211 are not shown) are arranged,
Each of the light emitting diodes 110', 111', 210
．． The light emitting surface 211 is formed in a rectangular shape. and,
Each of the light emitting diodes 110', 111', 210
．． 211 and the housing 1 facing each other with the eccentric circular roller 208 in between.
On the inner wall of the rear bottom plate 109 of 00 are phototransistors 112', 113', 2 having rectangular light-receiving surfaces.
12.213 is fixed.

Each of the light emitting diodes 110' and 111' is driven by a drive circuit 1241 for the light source 120 that controls the amount of light emitted by a pulse width modulated sine wave or cosine wave as in FIG.
25 and also 1 light emitting diode 210.211
are connected to respective drive circuits (not shown) that control the amount of light emitted by inverted signals of the sine wave and cosine wave, and each light emitting diode 110', 111', 21
From 0.211, ea shown in the above formula (2),
The amount of light emitted is eb+ eC+ ed. Also,
Each phototransistor 112', 113', 2
The output voltage of 12.213 is applied as an addition signal to an addition/subtraction calculator, and the output of the addition/subtraction calculator is introduced to a bypass filter.

In the above configuration, when the detection shaft 103 is rotated, the eccentric transmission circular rotor 208 rotates as a single body.

Each light emitting diode 110', 111', 210
．． Of the light emission amount of 211, each opposing phototransistor 112'.

The amount of light reaching 113', 212, and 213 is determined by the rotation angle θ of the detection axis 103, respectively, as shown in equation 13 ha' p llb' * hj t hd', and as a result, each phototransistor 112'
, 113', 212.213 is I shown in the above α4 formula
A', lb*1(', Id') are generated. Then, the voltage signals Ia' to +d/ are added by an adder/subtractor to obtain a quadratic addition output S.

S = 2KB cosθsinωt −2KB s
inθcosωt+2 to 9&2+2Kg L”-(Rc
os(7)2-4x Q4 Here, x is a constant corresponding to the radius of the tracing light circle at the center of the rotor.This addition output is then used in the bypass filter as
The low frequency components, that is, the components of the third and fourth terms in Equation 34 above, are removed, and the phase is shifted to the detection axis 1 as shown in Equation 33 above.
A phase signal proportional to the rotation angle θ of 03 is extracted. In the above embodiment, the light emitting surface of the light source and the light receiving surface of the light receiving element are formed in a rectangular shape, but the same effect can be achieved even if only one of them is formed in a rectangular shape.

Instead of forming the light emitting surface and light receiving surface into rectangular shapes.

The same thing can be done even if a mask having a rectangular slit is provided on the front surface of the mask.゛In addition, in the above embodiment, FIG. 14 and part 1)-
As shown in FIG. 15, which shows a cross section in the vertical direction, the rotor is a transparent circular rotor 308 with slits, which has a slit disk 305 added to the outer periphery of the transparent disk 205, and the slit disk is sandwiched between the rotor. Two pairs of light emitting diodes and phototransistors facing each other, 310 and 312. 311 and 3
13.

311 (not shown) are arranged with a pitch shifted by (n + 1/4) of the slit pinch, and the light emitting diodes 310 , 311 and phototransistors 312 . The same circuit as that in FIG. 8 is used for the light emission and output processing of 313, that is, these are connected to the light emitting diode 110. 111. Phototransistor 11
2. 113 and each drive circuit 124,
125. As a result, a phase signal having a phase corresponding to the rotation angle θ of the detection shaft 103 as well as a phase signal corresponding to the rotation angle θ of the detection shaft 103 is generated at the same time. The phase of Zθ with respect to θ (however,
It may also be possible to extract a phase signal having Z (Z is the number of slits in the slit disk 305). In other words, the opposing area of the light source and the light receiving element placed across the slit is the detection axis 1.
03 changes in a substantially sine wave shape every time the pitch angle of the slit rotates, and this slit also becomes a kind of light amount changing means. Therefore, from now on, an expanded phase signal in which the pitch angle θ of the slit has a phase of 360 degrees can be obtained, and by using this together with the above-mentioned phase signal, angle measurement with high resolution can be realized.

As described above, the present invention forms a signal having an amplitude or phase corresponding to the rotation angle by a photoelectric method that combines a photoelectric conversion means, a light amount changing means, and a signal conversion means.

Therefore, the frequency of the light source drive signal can be made sufficiently large as required, and since the rotor only has the function of changing the amount of light, its moment of inertia can be made extremely small, and as a result, high responsiveness can be achieved. Also, the signals sent and received between the stator and rotor are light, so.

No special sending/receiving device is required, and both parties can communicate without contact.

Furthermore, the overall structure is simple, making it easy and inexpensive to manufacture.

[Brief explanation of the drawing]

Figure 1 is a model diagram showing the principle of a known resolver;
FIG. 3 is a waveform diagram showing the excitation signal waveform and output signal waveform of the resolver, and FIG. 4 is a block diagram showing an example of a signal converter that further converts the amplitude signal of the resolver into a predetermined angle signal. 5 is a waveform diagram showing the waveforms of each part in FIG. 4, FIG. 6 is a partially sectional front view showing the first embodiment of the present invention, and FIG.
The figure is a sectional view taken along the line A-A in FIG. 6, FIG. 8 is a block diagram showing an embodiment of the light source of the present invention and a signal converter for forming a phase signal, and FIG. 9 is a drive signal waveform. Waveform explanatory diagram, FIG. 10 is a front view with a partial cross section showing the second embodiment of the present invention, FIG. 11 is a sectional view along the line C-C of FIG. 10, and FIG. 12 is a third embodiment of the present invention. FIG. 13 is a partially cross-sectional front view showing an example; FIG. 13 is a cross-sectional view along the line B-B in FIG. 12; FIG. 14 is a partially cross-sectional front view showing a fourth embodiment of the present invention; FIG. is a sectional view taken along the line D-D in FIG. 14. 0 103: Detection axis, 108.108', 208.308
: Rotor. 110, 111.111', 210.211: Light emitting diode. 112.113.112', 113', 212.2
13: Phototransistor, 105.105',
105": Polarizer plate, 2o5: Transparent disk, 305 Nislit disk, 116.117゜116': Polarizer plate application note /2I2) No. lt/, Figure No. I No. 73 (¥] 1? L2 箪 Is I21

Claims (1)

[Claims] ■ A rotor is rotatably supported within a sealed casing. a photoelectric conversion means in which a plurality of light sources whose light emission amounts are controlled by mutually in-phase or 90-degree phase sine wave drive signals and a plurality or shared light receiving element are arranged to face each other with a rotor in between;
A light amount changing means is provided for the photoelectric conversion means and the rotor, and changes the amount of transmitted light between the respective light sources and the light receiving elements in a sine wave shape with a mutual phase of 90 degrees. An angle measuring device comprising signal conversion means for converting the output of a light receiving element of a photoelectric conversion means into an angle signal. 2. The photoelectric conversion means is two light sources and two or a shared light receiving element, and the light amount changing means is a polarizer rotor formed by integrally fixing a polarizer plate. The angle measuring device according to claim 1, wherein the polarizer plate is arranged between each light source and the light receiving element with transmission axes shifted by 45 degrees from each other. 3. The photoelectric conversion means includes two light sources and two or a shared light receiving element, and the light amount changing means has a polarizer disk integrally fixed to the inner and outer circumferences of the rotor with transmission axes shifted by 45 degrees from each other. 2. The angle measuring device according to claim 1, comprising: a double polarizer rotor; and a polarizer plate disposed between each light source and the light receiving element provided between the inner and outer peripheries of the rotor. 4. The angle measuring device according to claim 1, wherein the photoelectric conversion means includes four light sources and four or shared light receiving elements, and the light amount changing means includes a polarizer plate arranged between polarizing elements. . 5. The photoelectric conversion means are arranged at 90 degrees to each other.
The light amount changing means has four light sources and four light receiving elements or a shared light receiving element, and the light amount changing means is an eccentric light transmitting internal rotor having an eccentric light transmitting interior formed on the loaf, and four light sources or four light receiving elements or both. On the other hand, the angle measuring device according to claim 1, wherein the photoelectric conversion means has a rectangular surface facing the rotor. 6. A patent claim in which the signal conversion means includes a bypass filter into which the output of the light receiving element or the output of the addition/subtraction calculator described below is input, and an addition/subtraction calculator into which the output of the bypass filter, the output of the light receiving element, or the sine wave drive signal of the light source is input. The angle measuring device according to any one of the ranges 1 to 5.