TWI518329B - Optical system for detecting wind - Google Patents

Description

Optical wind measurement system

The invention relates to an optical wind measurement system, in particular to replacing a coherent pulse laser with a continuous wave laser light and an optical focusing system, replacing the Fourier spectrum analysis with a voltage detection, and replacing the multi-axis with a single mirror single field and a photoelectric array. An optical wind measurement system that scans the system and single-mirror single field of view to form a very small viewing area that avoids errors in wide field of view in complex terrain areas.

Conventional fans use the tail wind speed and direction meter to measure the wind to control the fan pointing. In recent years, there have been the use of lasers for wind measurement. However, the problems of the conventional laser measurement system mainly include complex systems, high unit prices, and a wide field of view.

For the complexity of the system and the extremely high unit price, please refer to Figure 1. The conventional wind measurement system adopts stereo scanning, and its detection range presents a cone. As shown by the dotted line in Figure 1, the cone will follow the distance. Rapid expansion, it is easy to be blocked by terrain in complex terrain, and it is easy to be blocked by other fans in multi-tower fan environment, which will affect the detection results. In addition, the conventional wind measurement system is an interference amplification structure. After the emergence of the Doppler laser wind measurement technology, the laser is placed on the nacelle, and the wind field at the front edge of the fan can be measured hundreds of meters, effectively avoiding the blade. Interference from the flow field. However, the Doppler system needs to use a pulse coherence laser. At the same time, the system needs to perform Fourier operation in real time. The spectrum technology needs to use high-speed Fourier transform, and the data detection/analysis needs to use high-speed computing host, high computing demand and high. Power consumption, high consumables cost, the overall equipment is very complicated, and the unit price is extremely high, about 25,000~35,000 euros, and the life is short, generally not more than three years. Therefore, it is not universally applicable to the fan configuration.

Secondly, for the need to have a wide field of view, since the Doppler system measures the wind speed component on the laser path, the detection of the wind direction needs to be directed at different angles to obtain the direction of the wind, so the larger the angle it is good. But this will be hundreds of meters away. Forming a wide observation area, where there is a topographic effect, there is a potential problem of misjudgment.

In addition, the conventional wind measurement system takes priority in measuring the wind speed. For example, a wind speed detecting system is known which does not have a focusing device, and uses split transmission/reception, so a specific intersection position is required. In addition, the system does not use a single optical path, and the illumination area and intensity cannot be corrected, so Use peak detection, but this may detect independent events and affect the accuracy of the detection.

Accordingly, there is a need in the related art to provide an optical wind measurement system that "simplifies the laser source, simplifies the calculation, simplifies the observation area, and has a narrow field of view" to solve the related problems and increase the competitiveness of the wind measurement market. .

In one embodiment, the present invention provides an optical wind measurement system including a light source, a lens unit, a sensing unit, and a processing unit; the light source is configured to emit continuous wave laser light; and the lens unit is a single mirror single field of view. The lens unit has a first side and a second side opposite to each other, and the continuous wave laser light is incident on the lens unit from the first side, and forms a beam-expanded continuous-wave laser light on the second side, and the expanded-wave continuous laser light is focused. The sensing unit is disposed on the first side of the lens unit, and the echo signal is projected to the sensing unit through the lens unit to generate a voltage signal; the processing unit is coupled to the sensing unit The processing unit calculates the direction of a target according to the voltage change of the voltage signal.

100‧‧‧Optical wind measurement system

10‧‧‧Light source

200‧‧‧ Targets

20‧‧‧ lens unit

21‧‧‧ first side

22‧‧‧ second side

23‧‧‧ observation area

30‧‧‧Sensor unit

31‧‧‧ imaging surface

40‧‧‧Processing unit

4A, 4B, 4C‧‧‧ image changes

L10‧‧‧Continuous wave laser light

L20‧‧‧Expanded continuous wave laser light

P‧‧‧Detection location

S‧‧‧ echo signal

W‧‧‧Width

Figure 1 shows the wind measurement of a conventional fan

2 is a schematic block diagram of an embodiment of the present invention.

FIG. 3 is a schematic flow chart of measuring wind in the present invention.

4 is a schematic diagram of an echo signal of the present invention imaged by a sensing unit.

Referring to the embodiment shown in FIG. 2 and FIG. 3 , an optical wind measurement system 100 of the present invention includes a light source 10 , a lens unit 20 , a sensing unit 30 , and a processing unit 40 .

The light source 10 can emit a continuous wave of laser light, for example, a laser can be used. It is a light source 10 for emitting continuous wave laser light L10 of a non-coherent continuous wave.

The lens unit 20 is a single mirror single field of view. The lens unit 20 has a first side 21 and a second side 22 opposite to each other. The continuous wave laser light L10 is incident on the lens unit from the first side 21 and forms an expansion on the second side 22. The bundle of continuous wave laser light L20, the expanded continuous wave laser light L20 can be focused on a detection position P and return an echo signal S. The detection position P can be set as desired, for example, by changing lenses having different focal lengths, that is, different detection positions P, for example, 300 meters or other distances, or a zoom lens can be used to change different focus positions. Secondly, the expanded continuous-wave laser light L20 can form a very small observation area 23 on the second side 22, and the width W of the observation area 23 is approximately in the range of 5 to 30 cm, which is similar to the conventional conical expansion. In the observation area, the invention forms a very small observation area with a single beam and a single field of view, so as to avoid interference by other fans or terrain. When the echo signal S is returned, the echo signal S passes through the lens unit 20 and is then projected to the sensing unit 30.

The sensing unit 30 has an imaging surface 31. The echo signal S is projected on the imaging surface 31 to generate a voltage signal, and the strength of the voltage signal varies according to the change of the spatial object located at the detection position P. In the case of the atmospheric environment, it contains various substances such as air masses, water mist, and fine particles in the air mass, hereinafter collectively referred to as target 200. Referring to FIG. 2, the target object 200 flutters with the air, and when the target object 200 floats to the illumination range of the expanded continuous wave laser light L20 and the expanded continuous wave laser light L20 illuminates the target object 200, the echo signal It will be enhanced, that is, the voltage is strong, and after the target object 200 continues to flutter and escapes the illumination range of the expanded beam of the continuous wave laser light L20, the expanded beam of the continuous wave laser light L20 is irradiated to the atmosphere without the target object 200. In the region, the echo signal is weakened, that is, the voltage is low, so that the sensing unit 30 can form an image with different brightness and darkness.

Referring to FIG. 3 and FIG. 4, the processing unit 40 is coupled to the sensing unit 30, and the processing unit 40 can calculate the direction of the target 200 according to the voltage change of the voltage signal over a period of time. Figure 4 shows that when the time is about 5 seconds, 9 seconds, and 20 seconds, there is a target entering the detection position, thus causing image changes of the voltage signal 4A, 4B, 4C, and the rectangular changes of the image changes 4A, 4B, 4C. The images formed by the continuous beam laser light L20 that is expanded to the target object 200 are respectively reflected. Image change For 4A, the rectangular grid represents that the target object 200 enters the detection position P at about 19 seconds, and leaves the detection position P at about 21 seconds, but the distance is always maintained at about 1.5 kilometers, and no offset occurs. The orientation of the fan is consistent with the wind direction, and the image change 4B is the same. In the case of image change 4C, the rectangular grid represents that the target 200 enters the detection position P at about 7 seconds, and leaves the detection position P at about 11 seconds, and the distance is shifted from about 2.3 kilometers to 2.2 kilometers. The direction of the fan is inconsistent with the direction of the wind. The oil processing unit 40 calculates the time difference between the voltage changes of the voltage signals and the direction of the target 200. The processing unit 40 can use programmable control (PLC control) to track the echo signal S profile of the target object 200 by expanding the continuous wave laser light L20, and perform calculation by voltage difference and voltage detection to obtain the target object. The direction and speed of movement of 200. The form of the sensing unit 30 is not limited. For example, a photoelectric array may be employed, and the left and right image positions may be distinguished by the photoelectric array on the imaging surface 31 to form two left and right observation regions, thereby identifying the left and right sides of the target 200. In addition, the time period during which the processing unit 40 captures the voltage signal can be set.

In summary, the optical wind measurement system provided by the present invention replaces the coherent pulse laser with continuous wave laser light and optical focusing system, replaces Fourier spectrum analysis with voltage detection, and combines single mirror single field and photoelectric array. Replacing the multi-axis scanning system and single-mirror single-field to form a very small observation area, without the need for stereo scanning, the spatial footprint is nearly uniform, thus avoiding the error of wide field of view in complex terrain areas, and can be used in multi-tower fans The use of complex terrain environment, no need for spectrum technology, no high-speed computing requirements, data detection can be simplified to potential detection, DSP / embedded system can be competent for computing. It has been verified that a single measuring point (500~1500 meters @5mW) can be achieved with the architecture of the invention, the data rate is less than five seconds, the angular resolution (horizontal) is about 1 degree, and the wind speed error is less than 0.5. Metrics per second (m/s), the cost is less than NT$450,000 (approximately 11,000 Euros). Accordingly, the present invention has the effect of "simplifying the laser source, simplifying the calculation, simplifying the observation area, and having a narrow field of view", and can solve the problem that the conventional wind measurement system is complicated, the unit price is extremely high, and a wide field of view is required. Reduce the unit cost, system complexity and azimuth misjudgment of the wind measurement system, thereby improving market competitiveness.

However, the specific embodiments described above are merely used to illustrate the features and functions of the present invention. The invention is not intended to limit the scope of the invention, and any equivalent changes and modifications made by the disclosure of the present invention should still be the present invention without departing from the spirit and scope of the invention. The scope of the patent application is covered.

100‧‧‧Optical wind measurement system

10‧‧‧Light source

200‧‧‧ Targets

20‧‧‧ lens unit

30‧‧‧Sensor unit

40‧‧‧Processing unit

Claims (8)

An optical wind measurement system comprising: a light source for emitting continuous wave laser light; a lens unit having a first side and a second side opposite to each other, the continuous wave of the laser light One side of the lens unit is incident on the second side to form a beam-expanded continuous-wave laser light, and the expanded continuous-wave laser light is focused on a detection position and returns an echo signal; a sensing unit is disposed And the processing unit is coupled to the sensing unit, and the processing unit is configured according to the sensing unit The voltage of the voltage signal changes to calculate the direction of a target. The target is a substance contained in the atmospheric environment and can float with the air, and the direction of the target is used to calculate the wind direction and the wind speed. The optical wind measurement system of claim 1, wherein the sensing unit is a photoelectric array, and the photoelectric array has an imaging surface, and the echo signal is projected on the imaging surface. The optical wind measurement system according to claim 2, wherein the left and right image positions are distinguished by the photoelectric array to form two left and right observation regions. The optical wind measurement system of claim 1, wherein the lens unit forms an observation area on the second side, and the width of the observation area is in the range of 5 to 30 cm. The optical wind measurement system of claim 1, wherein the processing unit calculates a time difference of the voltage change of the voltage signal to estimate the direction of the target. The optical wind measurement system according to claim 1, wherein the processing unit uses programmable control (PLC control) to track the echo signal profile of the target with the continuous wave laser light, and the voltage is The differential and voltage detection operations are performed to obtain the moving direction and speed of the target. The optical wind measurement system of claim 1, wherein the light source is a laser semiconductor for emitting non-coherent continuous wave laser light. The optical wind measurement system of claim 1, wherein the target is a particle in a gas mass, a water mist or an air mass.