JPH0650725Y2 - Solar tracking device - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sunlight tracking device for detecting the position of sunlight and tracking the sunlight, and more particularly to a sunlight tracking device for tracking the sunlight by digital processing.

[0002]

2. Description of the Related Art In a sunlight tracking device for tracking sunlight, it is necessary to detect the position of sunlight, and a sunlight position detecting device is used for this purpose. The conventional sunlight position detecting device mainly uses two or a plurality of photosensors such as photodiodes and detects the position by differentially using these analog outputs. However, since this differential type detection apparatus performs detection by analog signal processing, there is a problem that the sensor element undergoes a considerable change over time, such as a decrease in output and drift, and detection accuracy decreases.

Further, if a correction circuit or the like for correcting these secular changes is provided, the whole structure becomes complicated and the price of the apparatus becomes expensive, which is a new problem. Further, in such a differential type detection device, it is necessary to precisely set the positional relationship between the sun and the sensor.

Further, conventionally, there is a device using a PSD (Position Sensitive Device) in addition to the above-mentioned differential type detecting device, but in this case as well, since detection is performed by analog signal processing, secular change and temperature There are problems such as drift.

[0005]

[Problems to be solved by the invention] As described above,
Since the detection process is performed in an analog manner, there is a drawback that the detection error becomes large and the accuracy decreases.

The present invention has been made in consideration of the above circumstances, and its purpose is to detect the position of sunlight with high detection accuracy with little change over time, and thus to track sunlight with high accuracy. It is to provide a solar tracking device that can perform.

[0007]

A solar light tracking device according to the present invention comprises a dark box having first and second dark chambers, and first and second slits provided in the first and second dark chambers. A first one-dimensional solid-state imaging device, which is installed in the first dark room and includes a plurality of pixels for horizontally detecting sunlight passing through the first slit; A second one-dimensional solid-state imaging device that is installed in a room and includes a plurality of pixels that vertically detect sunlight passing through the second slit, and the first and second one-dimensional solid-state imaging devices. First and second position data detection circuits for obtaining position data in the horizontal and vertical directions of sunlight based on the output of the device, preset position data in the horizontal direction, and the sun obtained by the first position data detection circuit. Based on horizontal position data of light First displacement amount calculating means for calculating a displacement amount to be supplied to the horizontal drive device, preset position data in the vertical direction, and position data of the sunlight in the vertical direction obtained by the second position data detection circuit. And a second displacement amount calculating means for calculating a displacement amount to be supplied to the vertical direction driving device based on the above, wherein each of the first and second position data detection circuits is the one-dimensional solid-state imaging device. Of the pixels, the signal obtained by sequentially reading and scanning the pixels is compared with a predetermined threshold level to generate a pulse signal, a divider circuit that divides the output pulse signal of the comparator circuit by ½, When the read signal level of the one-dimensional solid-state imaging device is less than or equal to the threshold level, the signal corresponding to the synchronization signal used when reading the signal from the one-dimensional solid-state imaging device is counted. , Readout signal level of the one-dimensional solid-state imaging device is characterized in that once they become equal to or greater than the threshold value level is composed of a counter circuit for counting an output pulse signal from the frequency divider.

[0008]

In the solar tracking device of the present invention, when the signal read from the one-dimensional solid-state image pickup device is below the predetermined threshold in the first and second position data detection circuits, the signal is read from the one-dimensional solid-state image pickup device. The counter circuit counts the signal corresponding to the synchronization signal used for the pixel count from the pixel at one end of the one-dimensional solid-state imaging device to the end of the region irradiated with sunlight of a predetermined light amount or more. You get a number. After the read signal level from the one-dimensional solid-state imaging device becomes equal to or higher than the threshold value, the counter circuit counts the pulse signal from the frequency dividing circuit, so that the one-dimensional solid-state imaging device is irradiated with the predetermined amount of sunlight or more. The number of pixels up to the center of the existing area can be obtained. The number of both pixels becomes the position data of the sunlight in the horizontal direction and the vertical direction, and the position data of the sunlight in the horizontal direction and the vertical direction obtained by the first and second position data detection circuits are combined with the preset position data. The displacement amounts are supplied to the first and second displacement amount calculation means, and the displacement amounts to be supplied to the horizontal and vertical direction drive devices are calculated by these first and second displacement amount calculation means.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be described below with reference to the drawings.

First, the principle will be described before the description of the embodiment of the present invention. FIG. 4 is a diagram for explaining the principle of the solar light tracking device according to the present invention. In the figure, 14 is a one-dimensional sensor in which a plurality of pixels SC are arranged in a line, and 16 is a slit plate. Here, sunlight 18 is applied to the sensor 14 via the slit plate 16. At this time, the slit width of the slit plate 16 is S, the incident angle of the sunlight 18 is θ, the distance between the slit plate 16 and the light-receiving surface of the sensor 14 is d, and the viewing angle of the sun is α (the sun viewed from the viewpoint). Apparent size, usually about 0.54
°), the photosensitive width on the sensor is b, the number of pixels of the sensor 14 is N, the slit center of the slit plate 16 is C, and the slit center C
The photosensitive width b on the sensor is given by the following equation, where C'is the orthogonal projection of the image on the sensor and Cs is the center of the sunlight incident from the slit on the sensor. However, at this time,
The diffraction effect at the slit edge is ignored. b = S + d [cot {θ− (α / 2)} − cot {θ + (α / 2)] = S + d · sin α / [sin {θ− (α / 2)} · sin {θ + (α / 2)] … 1

As is clear from the above equation 1, the photosensitive width b is a function of the slit width S and the viewing angle α of sunlight, and has a peak having a certain width (plateau). However,
This width is sufficiently larger than the value calculated by the diffraction effect at the slit edge. Then, by detecting the sensor center Cs which is the center of the photosensitive width b, the distance between C ′ and Cs can be obtained, and the incident angle θ of sunlight is obtained from the relationship between this distance and the distance d. be able to. The position of the sunlight can be detected by providing the detecting means for such an angle θ in the horizontal direction and the vertical direction, respectively. Next, an embodiment of the solar light tracking device of the present invention will be described.

3A and 3B show the appearance of the entire sunlight position detecting device used in the sunlight tracking device according to the present invention. FIG. 3A is a perspective view and FIG. 3B is a front view.
(C) is a top view which shows the upper part of this sunlight position detection apparatus open.

In the figure, 10 is a dark box. This dark box 10
A dark room 12 partitioned by a partition plate 11 is provided inside. Furthermore, this dark room 12 has 12A and 12B by the separator 13.
It is divided into two chambers, and a plurality of pixels are arranged in a line on the partition plate 11 in one chamber 12A in order to detect sunlight in the horizontal direction (X direction). A one-dimensional solid-state imaging device, for example, a CCD / linear sensor 14A is installed. Similarly, a CC for detecting sunlight in the vertical direction (Z direction) is provided on the partition plate 11 in the other chamber 12B.
D / Linear sensor 14B is installed.

In front of the dark room 12, as shown in FIG. 3B, there are an X-direction slit 15A and a Z-direction sensor 14B extending in a direction orthogonal to the pixel array of the X-direction sensor 14A. Z extended in the direction orthogonal to the pixel array
A slit plate 16 provided with a directional slit 15B is arranged, and in front of the slit plate 16 a filter for dimming made of heat ray reflecting glass, heat ray absorbing glass or the like.
17 are arranged. Then, when detecting the sunlight position, the front of the dark box 10 is installed so as to face the sunlight.

FIG. 1 is a circuit diagram showing a configuration of an electric circuit for processing a signal obtained by the X-direction sensor 14A or Z-direction sensor 14B, and FIG. 2 is a timing chart thereof. Since this electric circuit has the same configuration for both the X and Z direction sensors, only one of the circuits will be described below.

The sensor 14 includes a transfer pulse φT, a reset pulse φR, two-phase shift pulses φA and φB, and their inversion pulses / φA and / φB (however, in FIG. 2, they are shown in FIG. 2). Inversion pulse / φ
A and / φB are driven by (not shown). That is, the sensor 14 is supplied with the transfer pulse φT and then the two-phase shift pulses φA and φB and their inversion pulses /
The signals of each pixel are sequentially read out in synchronization with φA and / φB,
Reset pulse φR for the signal of the pixel that has finished reading
Reset based on. As a result, as shown in FIG. 2, the sensor 14 sequentially outputs the voltage signal SO corresponding to the irradiation light amount of sunlight for each pixel. Ie the sensor
The voltage signal SO output from 14 is a comb-shaped signal having a voltage corresponding to the sunlight level for each pixel.

The signal SO is supplied to the comparator 21, which is given a predetermined threshold voltage. The comparator 21 outputs the "1" level signal only when the level of the signal SO is higher than the level of the threshold value Vth. Therefore, as shown in FIG. 2, the comparator 21 outputs a pulsed signal CO when the signal SO is equal to or higher than the Vth level.

The signal CO from the comparator 21 is a frequency divider circuit.
22 and the signal detection circuit 23. The frequency divider circuit 22 frequency-divides the signal CO by half and supplies the signal .phi.a as shown in FIG. The signal detection circuit 23 generates the detection signal φD which becomes the "1" level at the timing when the signal CO rises to the "1" level for the first time.

The other input of the digital multiplexer 24 is an inverted pulse / φR of the reset pulse φR.
Also, an inverted pulse of the transfer pulse φT / OR signal / φR · / φT of φT is supplied. Then, the signal φD is supplied to the multiplexer 24 as a selection control signal, and the multiplexer 24 selects the signal / φR · / φT when the signal φD is at “0” level and when the signal φD is at “1” level. Selects the signal φa.

The selection output φci from the multiplexer 24 is counted by the counter circuit 25. The counter circuit 25 is reset in a predetermined cycle based on the reset pulse φSR. The count output Ncl is supplied to the latch circuit 26.

The latch circuit 26 is supplied with the detection signal φD in addition to the count output Ncl of the counter circuit 25, and latches
These are latched based on the pulse φL. Latch circuit 26
The count value Ncl latched by is supplied to the arithmetic circuit 27.
The arithmetic circuit 27 calculates the incident angle θ of the sunlight in the direction (X direction or Z direction) from the count value Ncl from the latch circuit 26 and various values given in advance.

Here, when the voltage signal SO of each pixel read from the sensor 14 is lower than the threshold voltage (Vth level), the synchronizing signal / φR · / φT corresponding to each pixel of the sensor 14 is input to the counter circuit 25. Is supplied. For this reason, in this period, the counter circuit 25 counts the number of pixels from the pixel at one end of the sensor 14 to the end of the region where the predetermined amount of light or more (corresponding to the voltage level Vth) of sunlight is irradiated. It will be. Further, when the signal SO becomes higher than the threshold voltage level, φa is supplied as an input to the counter circuit 25. Since this signal φa is a 1/2 frequency-divided signal of the signal SO output corresponding to each pixel, in this period, the counter circuit 25 causes the sensor 14 to irradiate sunlight with a predetermined light amount or more. The number of pixels from the pixel at the end of the existing area to the pixel at the center of the area is counted.

Therefore, the count value Ncl of the counter circuit 25 is
The number corresponds to the number of pixels from the end of the sensor 14 to the center of the area irradiated with sunlight having a predetermined light amount or more. That is, in the principle diagram of FIG.
If the number of the pixel located at the end on the side is na and the number of the last pixel exceeding the threshold voltage level Vth is nb, Ncl is given by the following equation. Ncl = na-1 + {(na + nb + 1) / 2} ... 2

The value Ncl given by this equation is the number of the pixel Cs in FIG. Then, this value becomes the central value on the sensor 14 of the sunlight incident from the slit 15,
It is not affected by the width of the slit 15.

Further, in the arithmetic circuit 27, the distance d in FIG. 4 (distance between the slit plate and the light receiving surface of the sensor),
The width a of one pixel of the sensor and the number Nc ′ of the pixel C ′ at the position corresponding to the orthogonal projection of the slit center C on the sensor are given in advance. By the way, the above d, a, Ncl, Nc '
And the incident angle θ of sunlight is d tan θ = (Ncl−N
There is a relationship such as c '). Therefore, the arithmetic circuit 27 calculates the incident angle θ based on the following three expressions derived from the above relationship. θ = tan ⁻¹ (a / d) (Ncl−Nc) ... 3

Further, the output φD from the signal detection circuit 23 enables discrimination between fine weather and cloudy weather and detection of the presence or absence of sunlight. That is, the light incident from the slit 15 is a mixture of direct light from the sun and scattered light. When there are many direct light components, a large peak appears in the sensor output. 5 (a), (b), and (c) show fine weather, sunset or sunrise, and cloudy weather (cloudy weather here means that there is no direct light from the sun and only scattered light components are incident. FIG. 3 is a diagram showing a sensor output waveform in each case. In addition, e in FIG. 5 is a scattered light component. Therefore, if a predetermined threshold voltage level Vth is set by the comparator 21 and the signal φD from the signal detection circuit 23 rises to the "1" level, it can be determined that it is either fine weather, sunset, or sunrise. If the signal φD does not rise to the “1” level and remains at the “0” level, it can be determined that it is cloudy.

In this sunlight position detecting device, since the detecting means for the angle θ is provided in two systems, one for the horizontal direction and the other for the vertical direction, the position of the sunlight can be recognized by the detected angle θ in both means. it can. The minimum measurable angle θ min in this embodiment is given by the following equation near Nc ′. θ min = tan ^-1 (a / d) ... 4

The measurable range is tan ^-1 (a / d)
It is given by (1-Nc ') to tan ^-1 (a / d) (N-Nc'). Especially when Nc 'is in the center of the sensor, it is approximately ± tan ^-1 (a / 2d) N. That is, N, a
When d is constant, the minimum measurable angle and measurable range can be determined by appropriately setting d.

FIG. 6 is a sectional view in the length direction of the slit. The vertical sensitivity of the sensor 14 depends on l and d, where l is the length of the slit. When the sensor 14 is placed at the center of the slit, the measurable range is about ± tan ^-1 (l / 2d) with respect to the vertical direction of the sensor, and the range can be freely adjusted by setting l. You can

As described above, in the sunlight position detecting device having the above-mentioned configuration, since the signal processing after the comparator 21 is digitally performed, there is a secular change compared with the conventional case where all analog processing is performed. The number of errors is small and the error is small, so that the detection accuracy can be improved.

Next, an embodiment of the solar light tracking device of the present invention using the solar light position detecting device having the above structure will be described. FIG. 7 is a block diagram showing the configuration of a part of this solar light tracking device. The position data based on the angle θ of sunlight in the X direction obtained by the sunlight position detecting device is supplied to the subtraction circuit 31 as one input. Preset position data is supplied to the subtraction circuit 31 as the other input.
Then, the X-direction displacement amount calculated by the subtraction circuit 31 is supplied to an X-axis drive device (not shown). Similarly, position data based on the angle θ of sunlight in the Z direction obtained by the sunlight position detecting device is supplied to the subtraction circuit 32 as one input and preset position data as the other input. Then, the Z-direction displacement amount calculated by the subtraction circuit 32 is supplied to a Z-axis drive device (not shown). In this way, by controlling the operation of the drive device based on the difference between the preset position data and the current position data, the sunlight will enter the position determined by the preset position data of the sensor, Tracking is realized.

Since this tracking operation is controlled only by digital numerical calculation processing, ambiguity such as drift is eliminated as compared with the case where the operation is controlled based on an analog value. Further, since the relative positional relationship between the sensor and the sun is also determined by the preset position data, complicated adjustment such as alignment is unnecessary. Further, if the position encoder is provided in the drive device that operates based on the difference between the preset position data and the current position data, the absolute position of the sun can be detected. Furthermore, if the sensor is fixed, the absolute position of the sun can be calculated within the sensor measurable range by numerical calculation processing. Furthermore, by disposing a lens or the like in front of the sensor, a wider range of measurement becomes possible.

It is needless to say that the present invention is not limited to the above embodiment and various modifications can be made. For example, in the above embodiment, the case where the sensor 14 is a CCD / linear sensor has been described.
You may make it use the line sensor which performs the same operation | movement as a CCD sensor, such as a type | mold.

[0034]

As described above, according to the present invention, the solar light tracking device capable of detecting the position of the sunlight with high detection accuracy with little change over time, and capable of tracking the sunlight with high accuracy. Can be provided.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of an electric circuit of a sunlight position detecting device used in the sunlight tracking device of the present invention.

FIG. 2 is a timing chart of the electric circuit of FIG.

3A and 3B are external views of the solar light position detection apparatus, in which FIG. 3A is a perspective view, FIG. 3B is a front view, and FIG.

FIG. 4 is a diagram for explaining the principle of the solar light tracking device according to the present invention.

5 shows a sensor output waveform of the electric circuit of FIG.
(A) is a waveform diagram at the time of fine weather, (b) is a waveform diagram at the time of sunset or sunrise, (c) is a waveform diagram at the time of cloudy weather.

FIG. 6 is a diagram showing a relationship between a slit and a sensor in the sunlight position detecting device.

FIG. 7 is a block diagram showing a partial configuration of the solar light tracking device of the present invention.

[Explanation of symbols]

10 ... dark box, 14 ... CCD / linear sensor, 15 ... slit,
21 ... Comparator, 22 ... Frequency divider circuit, 23 ... Signal detection circuit,
24 ... Digital multiplexer, 25 ... Counter circuit, 26
... Latch circuit, 27 ... Arithmetic circuit, 31, 32 ... Subtraction circuit.

Claims (1)

[Scope of utility model registration request] 1. A dark box having first and second dark chambers, first and second slits provided in the first and second dark chambers, and a dark box installed in the first dark chamber. A first one-dimensional solid-state imaging device composed of a plurality of pixels for detecting sunlight passing through one slit in the horizontal direction; and a first one-dimensional solid-state imaging device installed in the second dark room and passing through the second slit. A second one-dimensional solid-state imaging device including a plurality of pixels for detecting sunlight in the vertical direction, and horizontal and vertical directions of the sunlight based on outputs of the first and second one-dimensional solid-state imaging devices. First and second position data detection circuits for obtaining position data in the horizontal direction, and horizontal drive based on preset position data in the horizontal direction and position data in the horizontal direction of sunlight obtained by the first position data detection circuit. Displacement amount to supply to the device First displacement amount calculation means for calculating, and preset position data in the vertical direction and position data in the vertical direction of sunlight obtained by the second position data detection circuit for supplying to the vertical direction drive device. A second displacement amount calculating means for calculating a displacement amount, wherein each of the first and second position data detection circuits reads signals obtained by sequentially reading and scanning pixels of the one-dimensional solid-state imaging device. A comparison circuit that generates a pulse signal by comparing with a predetermined threshold level, a frequency division circuit that divides the output pulse signal of the comparison circuit by 1/2, and a read-out signal level of the one-dimensional solid-state imaging device is the threshold value. When the level is lower than the level, the signal corresponding to the synchronization signal used when reading the signal from the one-dimensional solid-state imaging device is counted, and the read signal level of the one-dimensional solid-state imaging device is counted. A solar tracking device, comprising: a counter circuit that counts the output pulse signal from the frequency divider circuit after the bell becomes equal to or higher than the threshold level.