JPS636417A - Rotational position detecting device - Google Patents

Abstract

PURPOSE:To obtain an electric angle with an electric angle (n) times a spatial angle by arranging a shield plate which rotates together with a rotary body between a light emitting body and a light receiving body at specific intervals and providing light transmitting windows to the shield plate to a specific angle. CONSTITUTION:While (n) windows 31 and 32 in the same shape are fitted to the shield plate 3 at intervals of 360 deg./2n to 360 deg./2n, (m) set of (up to n) light receiving parts 41 and 42 in the same shape are arranged on the light receiving body 4 at mutual intervals of 360 deg./2n to 360 deg./2n and the sum of output voltages of the light receiving parts 41 and 42 is obtained. Consequently, the output voltages vary with function (n) times the angle of rotation and further its maximum values are determined irrelevantly to the number (n) of electrode couples, so that a decrease in detection accuracy is evaded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a detection device that uses light to detect the position of a rotating body as a function of rotation angle.

[Conventional technology]

Conventionally, various devices of this type have been proposed, such as those that detect using a sine or cosine function,
There are synchro electric machines such as resolvers that utilize electromagnetic coupling.

FIG. 2 is a principle configuration diagram showing the principle of the resolver, and FIG. 2A is a waveform diagram for explaining its operation.

As shown in FIG. 2, the resolver consists of a stator 10 and a rotor 11, each having a winding, and the rotor 11 is attached to a rotating body (not shown).

Therefore, the degree of coupling between these two windings changes according to the rotation of the rotating body. position), it is made to be a sine or cosine function as shown below.

Now, the stator winding is VB (
When excited with a voltage of = VO51flωt), the rotor winding outputs an amplitude-modulated signal such as vR = VOcosθ5in (alt). Here, if dθ/dt<< ω, the waveform of vR above is The signal becomes as shown in Fig. 2A (b), and when synchronous rectification is performed using Vs, a signal as shown in Fig. 2A (c) is obtained.Next, when the ω component of this signal is removed by a low-pass filter etc., the signal shown in Fig. 2A ( A cosine signal of θ can be obtained as shown in (d).A sine signal can be obtained by changing the spatial arrangement of the rotor windings by 90 degrees.

However, in this type of system, (a) windings are required for the stator and rotor, so there is a limit to miniaturization and weight reduction, and it is relatively expensive.

Since it uses electromagnetic coupling, an excitation signal is required as a carrier wave, and a demodulation circuit is required to obtain the sine and cosine signals of the position, making the electrical circuit part of the detector complex. .

C) Many methods have been proposed for obtaining rotor position signals without contact, but this requires the addition of several parts, which increases the size and cost.

There are other difficulties.

Therefore, the applicant has proposed a method that overcomes the above-mentioned difficulties by outputting the position of the rotating body as a function of the rotation angle using light (hereinafter referred to as the proposed method).
.

Figure 3 is a principle block diagram showing the principle of the proposed method.
Figure A is a reference diagram for explaining the transition of the light-receiving area (exposed area) observed through the window of the shroud in Figure 3;
FIG. 3B is a waveform diagram showing the output of the light receiving section.

In FIG. 3, 1 is the rotation axis of a rotating body (not shown), 2
6 is a light emitting body, 6 is a shield plate, 31 is a window for light transmission, 4 is a light receiving body, and 41 is a light receiving portion. That is, it has a light transmitting window 31 that transmits light by a rotation angle of 180 degrees from a predetermined reference axis that passes through the rotation axis, and has a light transmitting window 31 that transmits light by a rotation angle of 180 degrees from a predetermined reference axis that passes through the rotation axis. - On one side, a light emitting body 2 such as an LED (light emitting diode) that is formed in a ring shape and emits parallel light rays, and on the other side, a light receiving body 4 having, for example, a semicircular light receiving part 41, are arranged on the same axis. Deploy. child~
The light emitting body 2 and the light receiving body 4 are fixedly installed, and a predetermined interval is formed so that they do not come into contact with the rotating baffle plate 3.

Therefore, when the rotating body rotates, the door and shield plate 3 also rotate, and as a result, the portion of the light receiving section 410 visible through the window 31 of the screen plate 5, that is, the exposed portion, also changes. FIG. 3A shows the transition of this exposed area.

Now, as shown in Fig. 3A (a), the reference axis of the fixedly installed photoreceptor 4 is α, and the reference axis of the rotating baffle plate 3 is β.
If the angle of the β axis seen from this α axis is θ, then θ
As the bashing plate 3 rotates, (a), (b), and (
)・).

Assuming that the CCW (counterclockwise) direction of the knob and shield plate 3 is positive, this rotates from θ-0 in the CCW direction.
As a result, the exposed portion of the light receiving section 410 is 41'141''
, 41''', and its area S increases in proportion to θ.Then, when θ=π, this area S becomes maximum, and when θ>π, the area S decreases in proportion to θ. However, it becomes zero when θ=2π.

The third graph shows the change in area S with respect to θ.
This is diagram B, and it becomes a triangular wave as shown in the diagram.

Here, if a material that generates a voltage proportional to the amount of light, such as amorphous silicon, is used as the light receiving section 41, the generated voltage V. is proportional to the area S of the exposed light receiving section 41, so the triangular wave in the figure is proportional to θ and the output voltage V.
. It also shows the relationship between Therefore, this output voltage V. The principle of the proposed method is that the position of the rotating body can be determined by measuring the .

FIG. 4 is a schematic diagram showing a modification of the proposed method, and FIG. 4A is a waveform diagram showing the output of FIG. 4.

This is done so that the area of the two light receiving sections 42 and 43 when viewed from the window 31 of the shingle plate 3 is a sine function of the angle θ, as shown in FIG. By doing so, a two-phase output V1+v2 having a phase difference of 90 degrees as shown in FIG. 4A is obtained.

However, in such a proposed method, one period of the rotation angle is equal to one period of the output signal, and for example, the mechanical rotation angle is 1/n (n=2 , 3...) is impossible to obtain. Therefore, by attaching multiple windows to the keijahei board, the applicant achieved the above 1! A multipolar system is proposed to overcome these difficulties.

FIG. 5 is a principle configuration diagram showing the principle of such a multipolar system,
This shows an example where the output voltage is a function of twice the rotation angle (n=2).

In other words, the basic configuration of FIG. 5 is the same as that of FIG. 3, but the window 31 has the same shape over the spatial angle of -360 degrees = 90 degrees (1 opening 2) n. While providing two .32,
The difference from FIG. 3 is that one light receiving section 41 is formed over 90 degrees.

Therefore, in this case as well, let the reference axis of the photoreceptor 4 be α, the reference axis of the rotating shield plate 5 be β, and let the angle of the β axis seen from this α axis be θ, then θ is (A) and (B) in Fig. 5A as the rotation of .

It changes as shown in (c). The light receiving sections 41' and 41'' in FIG.
It receives light that has passed through //. At this time, window 31.
Area S and output voltage V of the light receiving section visible through 52.

is shown in Fig. 5B, and it can be seen that it is a function of θ which is twice the rotation angle l (the period is 1/2). Since the constant for converting electric angles into square boxes is called the number of pole pairs, n will be referred to as the number of pole pairs below.).

Above, we have explained the case of a triangular wave as a function in the negative phase, but as shown in Fig. 4, the function of the output voltage can be changed by changing the shape of the light receiving part, and furthermore, it is possible to change the function of the output voltage by changing the spatial angle. By converting the angle of the electrical signal and attaching a plurality of light receiving sections with their positions shifted accordingly, it is also possible to make the output voltage multiphase.

[Problem that the invention seeks to solve]

However, with the above method, the number of pieces of poppy and hei board is reduced,
The same applies to the light receiving section. As the number of rounding and pole pairs increases (as n increases), the area of the light receiving section must be reduced. In other words, the maximum voltage output by the light receiving section is inversely proportional to the number of pole pairs, so if the number of pole pairs tS increases, an offset occurs.

A problem arises in that the accuracy decreases due to effects such as drift.

Therefore, the present invention uses light to detect the position of a rotating body as a function of the rotation angle, and when the output voltage is made to be a function of n times the rotation angle,
It is an object of the present invention to enable the maximum value of an output voltage to be determined independently of the number of pole pairs n, so that detection accuracy does not decrease as n increases.

[Means for solving problems]

m pieces (maximum n pieces) of light are received with the same shape over the entire area, and the sum of the output voltages of each light receiving part is calculated.

[Effect]

By doing the above, the output voltage not only becomes a function of n times the rotation angle, but also its maximum value can be determined independently of the number of pole pairs n, making it possible to avoid a decrease in detection accuracy. Become.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 1A is a waveform diagram showing the output of the light receiving section. As is clear from FIG. 1, its basic configuration is the same as that shown in FIG. However, unlike in FIG. 5, the photoreceptor 4 has two light-receiving sections 41.
42 are arranged over 90 degrees with an interval of 90 degrees in the same way as the windows 51 and 32, and the adder 5 is provided.

Therefore, the shielding plate 3 and the photoreceptor 4 are -360
It looks the same even if it is rotated by -1SO degree, and by adding the output voltages of the two light receiving sections in the adder 5, the output voltage of the light receiving section can be adjusted to Try to increase it more than usual. That is, for example, window 31
If the light passing through the window 32 illuminates the light receiving section 41, the light passing through the window 32 will illuminate the light receiving section 42, and since the area of the light receiving section visible from each window is equal, the output voltage v21゜v2
□ is the same, and the function of the output voltage v2 and the rotation angle, which are summed using the adder 5, only has twice the amplitude compared to the case where there is one light receiving part, but the function itself and the phase change. I will not do it. This relationship is shown in FIG. 1A.

From this, if the output voltage is a function of n times the rotation angle, then
The amplitude of the output voltage of each light receiving part is 1/n,
By summing the output voltages of m (up to n) light receiving sections, the maximum value of the output possible table for the entire output voltage can be made to be independent of n, and as a result, the detection accuracy can also be reduced to n. This will not cause any deterioration, and it will be possible to stably perform multipolarization.

Here, consider the case of nw5, for example. In this case, the five windows provided in the shingle board will be spaced at 36 degree intervals across . At this time, the light receiving area also spans 36 degrees, and 5
By arranging them and calculating the sum of their output voltages, the maximum value of the output voltage can be made the same as in the case where the number of pole pairs is 1 (m-1), as in the previously described embodiment. Note that the number of light-receiving elements actually placed on the light-receiving body may be less than five, but the maximum output value will be reduced by that amount, and the explanation in Figure 1 shows that it will become a multi-polar type. Easy to understand.

In other words, according to the present invention, the maximum output voltage K v of the multipolar position detector is based on the maximum value v1maX of max when the number of pole pairs is 1, then vn max
=-vl maX (n=2y3y..., m""2,3...
, n), and when the number of counter electrodes is determined, the number of m that can be selected is also determined. Also, since n and m are integers, the reference direct V
However, since the area of the light receiving section can be continuously changed, the actual output voltage vn can similarly take continuous values.

Above, we have explained the case of a triangular wave as a function in the - phase, but as shown in Figure 4, by changing the shape of the light receiving part, the function of the output voltage can be changed, and furthermore, the spatial fishing force angle and the electrical signal can be changed. As described above, it is possible to convert the output voltage into multiple phases by converting the angle and attaching a plurality of light receiving sections with their positions shifted from each other accordingly. Further, the present invention can also be applied to the system K (Japanese Patent Application No. 60-272574), which has already been proposed by the applicant, in which the direction of light is radial. Furthermore, this invention applies the same idea to the method already proposed by the applicant in which two light receiving sections are combined into a set and the output voltage is used differentially to remove the offset voltage included in the output voltage. It can be applied and will be placed in place.

〔Effect of the invention〕

According to this invention, a shielding plate that rotates together with the rotating body is arranged at a predetermined interval between a fixedly installed light emitting body and a light receiving body, and the shielding plate is arranged at a spatial angle of 2n. By providing n identically shaped light transmission windows in every other equally divided window, for example, by arranging them, the output can be adjusted while having an electrical angle that is n times the spatial angle, as in the case of a multipolar resolver. Since the maximum value of the signal can be determined independently of the number n of pole pairs, there is an advantage that a multipolar position detection device whose detection accuracy does not decrease as the number n of pole pairs increases.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 1A is a waveform diagram showing the output of the light receiving section, Fig. 2 is a principle block diagram showing the principle of the resolver, and Fig. 2A explains its operation. FIG. 3 is a principle block diagram showing the principle of the proposed method; FIG. 3A is an explanatory diagram for explaining the transition of the light receiving area observed through the window of the shiihei board in FIG. 3; Third
Figure B is a waveform diagram showing the output of the light receiving section, Figure 4 is a schematic diagram showing a modification of the proposed method, Figure 4A is a waveform diagram showing the output, and Figure 5 is the principle of the multipolar system. Block diagram, 5A
The figure is an explanatory diagram for explaining the transition of the light-receiving portion observed through the window of the shroud in FIG. 5, and FIG. 5B is a waveform diagram showing the output of the light-receiving portion. Code explanation 1... Rotating body, 2... Luminous body, 3...
...Shiyahei board, 31.31'~31''', 32.
32'~32///...Light transmission window, 4...
...Photoreceptor, 41, 41'~41''', 42~44
...... Light receiving section, 1o... Stator, 11.
... Rotor, V o + V 2 ... Rotation position detection force, 5 ... - Addition calculator. Agent Patent Attorney Akio Namiki Agent Patent Attorney Kiyoshi Matsuzaki Figure 1 Figure 1A Figure 2 Figure 2A (B) Figure 4 Figure 4A

Claims (1)

[Claims] A shielding plate that rotates together with the rotating body is placed coaxially between the fixedly installed light emitting body and the light receiving plate, and the shielding plate is attached to the shielding plate at a spatial angle of 2n (n is a positive integer with a minimum value of 2) N identically shaped light transmitting windows are provided every other equally divided window, while an electric signal of a predetermined function proportional to the amount of light is emitted to the light receiving plate. is a spatial angle of 360
m pieces formed over degree/2n (m=2, 3...
. . , n) A rotational position detection device characterized in that by arranging light receiving sections and adding the output voltages of each of the light receiving sections, an output m times that of a case where there is only one light receiving section is obtained.