CN117687439A - Heliostat closed-loop tracking control method, heliostat closed-loop tracking control system and readable storage medium - Google Patents

Abstract

The invention provides a heliostat closed-loop tracking control method, a heliostat closed-loop tracking control system and a readable storage medium, wherein the heliostat closed-loop tracking control method comprises the following steps: s1: presetting a heliostat center sub-mirror at the center of the heliostat; s2: an image acquisition device is arranged on the back of a central sub-mirror of the heliostat; s3: the image acquisition device acquires a picture PP, and determines the central normal line of the heliostat on the PPThe mark point coordinates O of (a); s4: acquiring a sun center position and a heat absorber center position through an image acquisition device; the sun center position is denoted as a in PP and the absorber center position is denoted as B in PP; s5: controlling the heliostat to rotate so that a point O falls at the middle position of a line segment AB; the invention realizes the closed loop control of the heliostat by applying the digital camera to the control of the heliostat, and can stably reflect sunlight to the heat absorber for a long time only by simply calibrating the heliostat, thereby greatly reducing the overall manufacturing cost of the heliostat.

Description

Heliostat closed-loop tracking control method, heliostat closed-loop tracking control system and readable storage medium

[ field of technology ]

The invention relates to the technical field of heliostat tracking control, in particular to a heliostat closed-loop tracking control method, a heliostat closed-loop tracking control system and a readable storage medium.

[ background Art ]

The control mode of heliostats in the tower type solar photo-thermal power station is mainly open-loop control, namely: comparing the actual position of the heliostat with the target position obtained by calculation, and controlling the heliostat to rotate so that the two positions coincide. Because the transmission system and the bracket system of the heliostat inevitably have systematic errors, the installation errors are also inevitably generated in the installation process of the heliostat, and the tracking errors of the heliostat are objectively generated. The traditional solution is to acquire a heliostat motion model by acquiring the central positions of the light spots of the heliostat at different moments and calculate and acquire the correction parameters of the heliostat, so that the heliostat can track the sun with higher precision in a short period, and the precision is lower and lower along with the time. The heliostat open-loop control method has the following problems: 1) long debugging time is needed, 2) real-time feedback cannot be obtained, and 3) the requirement on performance indexes of the mechanical transmission mechanism is high. Because the heliostat in the open loop control state is uncontrollable in posture, the converging efficiency of solar energy in the heat absorber area can be affected, and the power generation efficiency of the tower type photo-thermal power station is affected.

It is obvious that these problems can be solved by closed-loop control of heliostats, but the closed-loop control of heliostats is difficult to realize, and there are some scientific research institutions in the world for researching the closed-loop control of heliostats, for example: a light collimation sensor is arranged between the heliostat and the heat absorber, and whether the reflected light of the heliostat is on the connection line of the heliostat and the heat absorber can be detected. Although the method can realize the closed-loop control of the heliostat, a vertical rod with a light collimation sensor is required to be installed in front of the heliostat, so that the cleaning of the heliostat by a cleaning vehicle is affected, the problems of high manufacturing cost and long debugging period exist, and the control mode is rarely applied to practical projects. In addition, some heliostat closed-loop control patent technologies which are not practically applied exist, and the heliostat closed-loop control thought is as follows: the position of the sun is sensed by the spot sensor, and the actual position of the sun is compared with the target position calculated theoretically, so that the closed-loop control of the heliostat is realized. Although the method can realize the closed-loop control of the heliostat, the closed-loop object is the sun, the installation error is unavoidable in the process of installing the facula sensor, and the method does not realize the closed-loop control of the heliostat in a real sense.

Accordingly, there is a need to address the deficiencies of the prior art by developing a heliostat closed-loop tracking control method, system, and readable storage medium that solves or mitigates one or more of the problems described above.

[ invention ]

In view of this, the present invention provides a heliostat closed-loop tracking control method, system and readable storage medium, which implements closed-loop control of heliostats by applying a digital camera with a wide-angle and high pixels to control heliostats, so that the heliostats can stably reflect sunlight onto a heat absorber for a long time as long as simple calibration is performed on the heliostats, and the manufacturing and installation precision of a driving system and a bracket system of the heliostats for closed-loop control is not sensitive any more, thereby greatly reducing the overall manufacturing cost of the heliostats.

In one aspect, the present invention provides a heliostat closed-loop tracking control method, including:

s1: presetting a heliostat center sub-mirror at the center of the heliostat;

s2: an image acquisition device is arranged on the back of a central sub-mirror of the heliostat;

s3: the image acquisition device acquires a picture PP, and determines the central normal line of the heliostat on the PPThe mark point coordinates O of (a);

s4: acquiring a sun center position and a heat absorber center position through an image acquisition device; the sun center position is denoted as a in PP and the absorber center position is denoted as B in PP;

s5: controlling the heliostat to rotate so that a point O falls at the middle position of a line segment AB;

in the aspect and any possible implementation manner described above, there is further provided an implementation manner, where the heliostat center sub-mirror in S1 is transparent glass corresponding to a lens area of the image capturing device.

As described in the foregoing aspects and any possible implementation manner, there is further provided an implementation manner, where the method for presetting the heliostat center normal mark point O in S2 specifically includes: and a bright object and a long-focus camera are arranged below the heat absorber, the heliostat is moved to enable the normal line of the center of the heliostat to point to the bright object, the image of the bright object in the heliostat is observed through the long-focus camera until the image of the bright object appears at the center position of the heliostat mirror surface, and the coordinate of the bright object in the picture PP acquired by the image acquisition device is the mark point coordinate of the center normal line of the heliostat.

In aspects and any of the possible implementations described above, there is further provided an implementation in which the bright object is a light source or a mirror with reflected light, and the bright object and the tele camera are disposed in close proximity.

In the aspects and any possible implementation manner as described above, there is further provided an implementation manner, where the image capturing device is a large wide angle high pixel digital camera.

In aspects and any possible implementation manner as described above, there is further provided an implementation manner, wherein a main optical axis of the image capturing device is parallel to a heliostat center normal.

In the aspect and any possible implementation manner described above, there is further provided an implementation manner, wherein a light sensing surface of the image capturing device is parallel to a mirror surface of a heliostat center.

In aspects and any possible implementation manner as described above, there is further provided an implementation manner, where the heliostat closed-loop tracking control method further includes S6: and presetting a brightness ratio threshold, wherein after the heliostat is tracked in place, the brightness of the heat absorber is smaller than the threshold compared with the brightness of the sun, reflected light of other heliostats is not projected to the heat absorber, and if no image of the sun or the heat absorber is acquired, the acquired parameters cannot be put into a heliostat closed-loop control flow.

Aspects and any possible implementation manner as described above, further provide a heliostat closed-loop tracking control system for the heliostat closed-loop tracking control method, where the heliostat closed-loop tracking control system includes:

the heliostat center sub-mirror is arranged at the center of each heliostat, is transparent glass with the area equivalent to that of the lens of the image acquisition device and replaces the mirror surface of the corresponding area of the heliostat center;

the image acquisition device is arranged on the back of the central sub-mirror of the heliostat and is used for acquiring the central position of the sun and the central position of the heat absorber;

the heliostat control device is used for controlling rotation and orientation of a heliostat mirror surface;

the image acquisition and processing device is used for presetting and representing a central normal position O, a sun central position A and a heat absorber central position B of the heliostat;

and the information transmission device is used for transmitting information among the image acquisition device, the heliostat control device and the image acquisition processing device. Compared with the prior art, the invention can obtain the following technical effects:

the invention applies the digital camera to the control of the heliostat, realizes the closed-loop control of the heliostat, can stably reflect sunlight to the heat absorber for a long time only by simply calibrating the heliostat, and is insensitive to the manufacturing and mounting precision of the transmission system and the bracket system, thereby greatly reducing the overall manufacturing cost of the heliostat.

Of course, it is not necessary for any of the products embodying the invention to achieve all of the technical effects described above at the same time.

[ description of the drawings ]

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a process diagram providing for determining marker point coordinates of a heliostat normal in an acquired picture in accordance with one embodiment of the invention;

FIG. 2 is a block diagram providing a digital camera and image acquisition processor mounted on the back of a center sub-mirror of a heliostat mirror surface in accordance with one embodiment of the invention;

FIG. 3 is a block diagram illustrating the symmetry of the sun and heliostat reflected spots about a heliostat center normal mark point in accordance with one embodiment of the invention;

fig. 4 is a flowchart of a heliostat closed-loop tracking control method according to one embodiment of the invention.

[ detailed description ] of the invention

For a better understanding of the technical solution of the present invention, the following detailed description of the embodiments of the present invention refers to the accompanying drawings.

It should be understood that the described embodiments are merely some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The invention provides a heliostat closed-loop tracking control method, a heliostat closed-loop tracking control system and a readable storage medium, wherein the closed-loop control of the heliostat is realized by applying a digital camera with a large wide angle and high pixels to the control of the heliostat, so that the heliostat can stably reflect sunlight to a heat absorber for a long time only by simply calibrating the heliostat, and the manufacturing and mounting precision of a transmission system and a bracket system of the heliostat for the closed-loop control is not sensitive any more, thereby greatly reducing the overall manufacturing cost of the heliostat.

As shown in fig. 4, the present invention provides a heliostat closed-loop tracking control method, which includes:

s1: presetting a heliostat center sub-mirror at the center of the heliostat;

s2: an image acquisition device is arranged on the back of a central sub-mirror of the heliostat;

s3: the picture acquired by the image acquisition device is PP, and the central normal line of the heliostat is determined on the PPThe mark point coordinates O of (a);

s4: acquiring a sun center position and a heat absorber center position through an image acquisition device; the sun center position is denoted as a in PP and the absorber center position is denoted as B in PP;

s5: controlling the heliostat to rotate so that a point O falls at the middle position of a line segment AB;

and in the step S1, the central sub-mirror of the heliostat is transparent glass, and the image acquisition device is arranged on the back surface of the transparent glass. The mirror surface at the center of the heliostat can be customized, the area corresponding to the central sub-mirror is prefabricated into transparent glass during mirror manufacturing, holes with corresponding sizes can be formed in the mirror surface at the center of the heliostat, and the transparent glass is adhered to the corresponding area.

The method for presetting the heliostat center normal marking point O in the S2 specifically comprises the following steps: and a bright object and a long-focus camera are arranged below the heat absorber, the heliostat is moved to enable the normal line of the center of the heliostat to point to the bright object, the image of the bright object in the heliostat is observed through the long-focus camera until the image of the bright object appears at the center position of the heliostat mirror surface, and the coordinate of the bright object in the picture PP acquired by the image acquisition device is the mark point coordinate of the center normal line of the heliostat. The bright object is a light source or a mirror with reflected light, the bright object and the tele camera being positioned in close proximity. The image acquisition device is a large wide-angle high-pixel digital camera. The main optical axis of the image acquisition device is parallel to the central normal line of the heliostat. The light sensitive surface of the image acquisition device is parallel to the mirror surface of the center of the heliostat. The heliostat closed-loop tracking control method further comprises S6: and presetting a brightness ratio threshold, wherein after the heliostat is tracked in place, the brightness of the heat absorber is smaller than the threshold compared with the brightness of the sun, reflected light of other heliostats is not projected to the heat absorber, and if no image of the sun or the heat absorber is acquired, the acquired parameters cannot be put into a heliostat closed-loop control flow. Aspects and any possible implementation manner as described above, further provide a heliostat closed-loop tracking control system, which is used in the heliostat closed-loop tracking control method.

The invention also provides a heliostat closed-loop tracking control system for the heliostat closed-loop tracking control method, which comprises the following steps:

the heliostat center sub-mirrors are arranged at the center of each heliostat and are transparent glass with the same area as the lens of the image acquisition device, and replace the mirror surface of the corresponding area of the heliostat center. The method comprises the steps of carrying out a first treatment on the surface of the

The image acquisition device is arranged on the back of the central sub-mirror of the heliostat and is used for acquiring the central position of the sun and the central position of the heat absorber;

the heliostat control device is used for controlling rotation and orientation of a heliostat mirror surface;

the image acquisition and processing device is used for presetting and representing a central normal position O, a sun central position A and a heat absorber central position B of the heliostat;

and the information transmission device is used for transmitting information among the image acquisition device, the heliostat control device and the image acquisition processing device.

Example 1:

the invention provides a heliostat closed-loop tracking control device based on a digital camera, which comprises a large wide-angle high-pixel digital camera (hereinafter referred to as a digital camera), an image acquisition processor and a heliostat controller. The digital camera is connected with the image acquisition processor, the image acquisition processor receives pictures shot by the digital camera, analyzes the pictures, extracts the positions of the sun center and the heat absorber center in the pictures, and sends the processing results to the heliostat controller. The digital camera is arranged at the center of the heliostat, and the main optical axis of the digital camera is parallel to the center normal line of the heliostat. By controlling the rotation of the heliostat, the normal line of the heliostat is positioned at the angular bisector position of the angle AOB formed by the sun A, the central normal line marking point O of the heliostat and the target point B, and thus the heliostat can reflect sunlight to the target position. The tracking accuracy of the heliostat is required as long as the heliostat can accurately reflect sunlight to the heat absorber. In the process that the heliostat reflects sunlight to the heat absorber, the digital camera can shoot two bright objects of the sun and the heat absorber, the two objects are easy to identify and mark the center of the two bright objects in the shot picture, and if the coordinates of the center points of the sun and the heat absorber are symmetrical about the coordinates of the central normal marking point of the heliostat, the light spots of the heliostat are already beaten on the heat absorber. The heliostat closed-loop control can reduce the requirement on the manufacturing precision of the speed reducer and the bracket of the heliostat, and is beneficial to reducing the overall cost of the heliostat.

The hardware of the invention comprises a large wide-angle high-pixel digital camera, an image acquisition processor and a heliostat controller. As shown in fig. 2, the digital camera and the image acquisition processor are fixedly arranged in an auxiliary shell, the auxiliary shell is provided with a mounting surface, the light sensitive surface of the digital camera is parallel to the mounting surface of the auxiliary shell, and the long side of the rectangular light sensitive surface of the camera is parallel to the ground. The lens of the digital camera faces the mounting surface, and the lens of the digital camera is a glass lens capable of changing color according to the intensity of light so as to avoid damage to the photosensitive surface of the digital camera caused by sunlight. The area corresponding to the mirror center of the heliostat is transparent glass. The auxiliary shell is fixedly arranged in the transparent glass area.

The image acquisition processor is used for receiving and processing the pictures acquired by the digital camera, transmitting coordinates of the central position (A) of the sun and the central position (B) of the heat absorber in the pictures to the heliostat controller in a wired communication mode, and supplying power to the image acquisition processor and the digital camera by the heliostat controller. The computer and other devices can receive the pictures shot by the digital camera acquired by the image acquisition processor through wireless communication.

As shown in fig. 3, after the polygon heliostat reflects sunlight onto the heat absorber, the brightness of the heat absorber and its surroundings is relatively high, and the digital camera of the heliostat can observe two high-brightness objects at the same time: sun and heat absorber. The image acquisition processor acquires pictures shot by the digital camera and sends coordinates of a sun center (A) and a heat absorber center (B) in the acquired pictures to the heliostat controller, and when a central normal line marking point of the heliostat is positioned at the middle position of an AB line segment, a solar light spot reflected by the heliostat is hit on the heat absorber. If the central normal marking point (O) of the heliostat is not positioned at the central position of the AB line segment, the heliostat can be rotated to enable the two points to coincide, and then the heliostat light spot can strike the heat absorber.

When the heliostat is first installed, the coordinates (O) of the marked point of the central normal line of the heliostat in the acquired picture are first determined, and the sun center position and the target point position should be symmetrical about the point. The method for determining the coordinates (O) of the mark points is based on the imaging principle of a plane mirror: the image (N) and the object (M) are symmetrical about the plane mirror. An object which is convenient to observe is arranged at a position far away from the heliostat, meanwhile, an observer (such as a tele camera) is arranged at the position of the object (M), when the observer observes that an image (N) of the object (M) is arranged at the central position of the heliostat, a straight line MN is the central normal line of the heliostat, in a picture shot by a high-pixel digital camera arranged at the central position of the back of the heliostat, and the central position of the object (M) in the picture is the mark point coordinate (O) of the central normal line of the heliostat.

The heliostat controller records coordinates (O) of the heliostat center normal mark point in the picture. According to the coordinates of the sun center (A) and the heat absorber center (B) in the picture acquired by the image acquisition processor, whether the reflection light spot of the heliostat strikes the heat absorber or not can be judged. When the two points A, B are symmetrical about the O-point, the solar light spot reflected by the heliostat strikes the heat absorber. If the center normal marked point coordinate O of the heliostat is not the symmetrical center O' of the two points AB, rotating the heliostat to enable the two points to coincide, and the reflection light spots of the heliostat are hit on the heat absorber.

When the heliostat is initially installed, first, the coordinates (O) of a mark point of the central normal line of the heliostat in the acquired picture are determined, and the specific positioning method in this embodiment is as follows: a strong light source (such as a searchlight) is arranged on the heat absorption tower, and a long-focus digital camera (shown in figure 1) is arranged at a position close to the strong light source. And rotating the heliostat to enable the central normal line of the heliostat to point to a strong light source arranged on the heat absorption tower, so that the image of the strong light source falls on the central position of the central sub-mirror of the heliostat in the picture acquired by the long-focus digital camera, namely the position for arranging the digital camera. Because the heliostat is far away from the strong light source, the central point coordinate of the strong light source image in the image acquired by the image acquisition processor on the heliostat can be regarded as the mark point coordinate (O) of the central normal line of the heliostat. In the image acquired by the image acquisition processor, the sun center position (A) and the target point position (B) should be symmetrical about the point (O). The coordinates of the marker point (O) are saved in the heliostat controller.

Normal operating state: the heliostat controller controls the heliostat to rotate and reflects sunlight to the heat absorber. After most heliostats in the mirror field reflect sunlight onto the heat absorber, the brightness of the heat absorber and the upper and lower protection plates of the heat absorber is higher. Taking one heliostat in the heliostat field as an example, the difference between the correction mode of the present patent and the traditional correction mode is illustrated: the target position of the heliostat light spot is a heat absorber, and the light spot of the heliostat may not accurately strike the heat absorber due to various systematic errors, and the traditional heliostat deviation correcting method is as follows: and (3) the light spots of the heliostat are beaten on a digital camera which is arranged on the heat absorption tower and is used for correcting the deviation, the brightness of the light spots of the heliostat is observed through the digital camera, if the brightness is higher, the tracking is accurate, and if the brightness is lower (or not bright), the azimuth and pitching correction angles of the heliostat are modified until the brightness becomes higher. And (3) synthesizing correction results of the heliostat at a plurality of moments throughout the day, and carrying out regression calculation on correction parameters of the heliostat, wherein the tracking accuracy of the heliostat is higher in a period of time later. The heliostat deviation correcting mode is as follows: the digital camera arranged at the central position of the heliostat simultaneously observes the position of the sun and the position of the heat absorber, the image acquisition processor analyzes and processes the picture shot by the digital camera, the coordinates of the center of the sun and the center of the heat absorber in the picture are found, and the coordinates are transmitted to the heliostat controller. The controller calculates the center point coordinates (O ') of the two coordinates, compares the center point coordinates (O ') with the heliostat center normal marking point coordinates (O) stored in the heliostat controller, if the two points are coincident, the tracking of the heliostat is accurate, if the two points are not coincident, the height angle and azimuth angle of the heliostat (namely, the azimuth angle and the pitch angle correcting angle of the heliostat are modified) are adjusted, so that the point O ' is coincident with the point O, and the heliostat can accurately reflect sunlight to the heat absorber. According to the change conditions of azimuth and pitching correction angles of the heliostat at a plurality of moments throughout the day, the correction parameters of the heliostat can be calculated in a regression mode. Thus, the heliostat light spot can accurately track the sun and can accurately strike the light spot to any other specified position.

The heliostat closed-loop control device and the heliostat closed-loop control method realize closed-loop in the normal condensation power generation process. After the heliostat is tracked in place, the heliostat controller sends an instruction to the image acquisition processor to start to acquire pictures shot by the digital camera, if the brightness of the heat absorber is smaller than a set value compared with the brightness of the sun, the image acquisition processor sends a fault code 1 to the heliostat controller, if no image of the sun or the heat absorber exists in the acquired pictures, the image acquisition processor sends a fault code 2 to the heliostat controller, and if the heliostat controller receives fault code information, the parameters acquired by the closed-loop tracking control device cannot be put into a heliostat closed-loop control flow.

The heliostat closed-loop control device is arranged on the back of the central sub-mirror positioned in the center of the heliostat mirror surface, the heliostat is cleaned without damaging the device, and dust in front of the digital camera lens can be cleaned. By adopting the heliostat closed-loop control device and the heliostat closed-loop control method, whether all heliostats reflect sunlight to the heat absorber or not can be perceived by oneself in the process of tracking the sun, and the heliostat closed-loop control device and the heliostat closed-loop control method are irrelevant to the transmission precision, the bracket precision and the gravity deformation of the bracket, so that the requirement on the mechanical manufacturing precision of the heliostat can be reduced, and the manufacturing cost of the heliostat is greatly reduced.

The method, the system and the readable storage medium for heliostat closed-loop tracking control provided by the embodiment of the application are described in detail above. The above description of embodiments is only for aiding in understanding the method of the present application and its core ideas; meanwhile, as those skilled in the art will have modifications in the specific embodiments and application scope in accordance with the ideas of the present application, the present description should not be construed as limiting the present application in view of the above.

Certain terms are used throughout the description and claims to refer to particular components. Those of skill in the art will appreciate that a hardware manufacturer may refer to the same component by different names. The description and claims do not take the form of an element differentiated by name, but rather by functionality. As referred to throughout the specification and claims, the terms "comprising," including, "and" includes "are intended to be interpreted as" including/comprising, but not limited to. By "substantially" is meant that within an acceptable error range, a person skilled in the art is able to solve the technical problem within a certain error range, substantially achieving the technical effect. The description hereinafter sets forth the preferred embodiment for carrying out the present application, but is not intended to limit the scope of the present application in general, for the purpose of illustrating the general principles of the present application. The scope of the present application is defined by the appended claims.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a product or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such product or system. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a commodity or system comprising such elements.

It should be understood that the term "and/or" as used herein is merely one relationship describing the association of the associated objects, meaning that there may be three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

While the foregoing description illustrates and describes the preferred embodiments of the present application, it is to be understood that this application is not limited to the forms disclosed herein, but is not to be construed as an exclusive use of other embodiments, and is capable of many other combinations, modifications and environments, and adaptations within the scope of the teachings described herein, through the foregoing teachings or through the knowledge or skills of the relevant art. And that modifications and variations which do not depart from the spirit and scope of the present invention are intended to be within the scope of the appended claims.

Claims (10)

1. The heliostat closed-loop tracking control method is characterized by comprising the following steps of:

s1: presetting a heliostat center sub-mirror at the center of the heliostat;

s2: an image acquisition device is arranged on the back of a central sub-mirror of the heliostat;

s3: the image acquisition device acquires a picture PP, and determines the central normal line of the heliostat on the PPThe mark point coordinates O of (a);

s4: acquiring a sun center position and a heat absorber center position through an image acquisition device, wherein the sun center position is represented as A in PP, and the heat absorber center position is represented as B in PP;

s5: the heliostat is controlled to rotate so that point O falls in the middle of line segment AB.

2. The heliostat closed-loop tracking control method of claim 1, wherein the heliostat center sub-mirror is transparent glass with the same lens area as the image acquisition device, and the image acquisition device is arranged on the back of the transparent glass instead of the mirror surface of the corresponding region of the heliostat center.

3. The heliostat closed-loop tracking control method of claim 2, wherein the determining of the heliostat center normal in S3The method for marking the point coordinates O specifically comprises the following steps: and a bright object and a long-focus camera are arranged below the heat absorber, the heliostat is moved to enable the normal line of the center of the heliostat to point to the bright object, the image of the bright object in the heliostat is observed through the long-focus camera until the image of the bright object appears at the center position of the heliostat mirror surface, and the coordinate of the bright object in an image acquisition device acquisition picture PP is the mark point coordinate of the center normal line of the heliostat.

4. A heliostat closed-loop tracking control method according to claim 3 wherein the bright object is a light source or a mirror with reflected light, the bright object and the tele camera being disposed in close proximity.

5. The heliostat closed-loop tracking control method of claim 1, wherein the image acquisition device is a large wide-angle high-pixel digital camera.

6. The heliostat closed-loop tracking control method of claim 1, wherein the primary optical axis of the image acquisition device is parallel to the heliostat center normal.

7. The heliostat closed-loop tracking control method of claim 1, wherein the photosurface of the image acquisition device is parallel to the mirror surface of the heliostat center position.

8. The heliostat closed-loop tracking control method of claim 1, further comprising S6: and presetting a brightness ratio threshold, wherein after the heliostat is tracked in place, the brightness of the heat absorber is smaller than the threshold compared with the brightness of the sun, reflected light of other heliostats is not projected to the heat absorber, and if no image of the sun or the heat absorber is acquired, the acquired parameters cannot be put into a heliostat closed-loop control flow.

9. A closed loop heliostat tracking control system for use in a closed loop heliostat tracking control method of any of claims 1-8, comprising:

the heliostat center sub-mirror is arranged at the center of each heliostat, is transparent glass with the area equivalent to that of the lens of the image acquisition device and replaces the mirror surface of the corresponding area of the heliostat center;

the image acquisition device is arranged on the back of the central sub-mirror of the heliostat and is used for acquiring the central position of the sun and the central position of the heat absorber;

the heliostat control device is used for controlling rotation and orientation of a heliostat mirror surface;

the image acquisition and processing device is used for presetting and representing a central normal position O, a sun central position A and a heat absorber central position B of the heliostat;

and the information transmission device is used for transmitting information among the image acquisition device, the heliostat control device and the image acquisition processing device.

10. A machine-readable storage medium having instructions stored thereon for causing a machine to perform the heliostat closed-loop tracking control method of any of claims 1-8.