A heliostat control system image acquisition module online calibration method

Abstract

The application belongs to the technical field of photo-thermal power generation, and particularly discloses a kind of heliostat control system image acquisition module online calibration method, including mirror surface posture measuring equipment and computing device;The computing device obtains data from the mirror surface posture measuring equipment and the image acquisition module by wireless or wired mode.The mirror surface posture measuring equipment is used to measure the three-dimensional coordinates, latitude and longitude and altitude information of heliostat mirror surface angle point;The computing device is used for mirror surface posture resolving, controls the image acquisition module to collect image, saves image, identifies the sun image center image coordinate, image acquisition module posture resolving, heliostat mirror surface and image acquisition module angle deviation amount resolving.The application is based on heliostat posture and sun track information resolving heliostat control system image acquisition module actual posture, realizes a kind of high efficiency, high precision heliostat control system image acquisition module online calibration.

Description

Technical Field

[0001] This invention belongs to the field of concentrated solar power generation technology, specifically relating to an online calibration method for an image acquisition module of a heliostat control system. Background Technology

[0002] Heliostats are the core component of tower solar thermal power generation technology. Their function is to reflect sunlight that strikes their reflective surfaces back to a target area. When heliostats within a certain range simultaneously reflect sunlight to the target area, a high energy flux density of solar energy can be obtained in the target area, thus realizing the conversion of solar energy into heat energy and then into electrical energy. Since the sun is constantly in motion, the heliostats need to continuously adjust their attitude according to the sun's position to ensure that the reflected sunlight does not deviate from the target area. Therefore, a high degree of control precision is required for the heliostats.

[0003] By using a control method based on the image acquisition module, the long debugging time required by traditional open-loop methods can be effectively avoided, and the normal power generation time is not excessively occupied, ensuring the effective utilization of solar resources. However, attitude deviations in the image acquisition module during installation can affect the final control accuracy of the heliostat. Therefore, it is necessary to calibrate the image acquisition module of the control system to obtain the relative angular deviation between the image acquisition module and the heliostat mirror surface.

[0004] Conventional calibration methods involve indoor calibration using multiple marker points. This requires pre-measuring the 3D coordinates of each marker point and the image acquisition module before calibration. This method impacts the heliostat's production and installation schedule, necessitating not only a dedicated indoor area for calibration but also minimizing the impact of vibration on the calibration results. Furthermore, subsequent upgrades to the heliostat require recalibration of the control system's image acquisition module, increasing both maintenance time and costs. Therefore, a high-efficiency, high-precision online calibration system for the control system's image acquisition module is needed. This system should enable accurate calibration of the image acquisition module and can also be performed independently outdoors, providing effective support for the heliostat's commissioning and maintenance. Summary of the Invention

[0005] This invention addresses the challenges of high control precision requirements and complex outdoor lighting conditions in heliostat control systems for solar thermal power generation. It proposes a high-efficiency, high-precision online calibration method for the image acquisition module of a heliostat control system, based on information such as the heliostat's attitude and solar trajectory, to calculate the actual attitude of the module.

[0006] A method for online calibration of an image acquisition module in a heliostat control system includes a mirror attitude measurement device and a computing device; the computing device acquires data from the mirror attitude measurement device and the image acquisition module via wireless or wired means.

[0007] The mirror attitude measurement device is used to measure the three-dimensional coordinates, latitude, longitude and altitude information of the corner points of the heliostat mirror. It can be a total station or other surveying equipment, or a positioning device based on real-time dynamic carrier phase differential technology (RTK) or differential global positioning system (DGPS).

[0008] The computing device is used for mirror attitude calculation, controlling the image acquisition module to acquire images, saving images, identifying the coordinates of the center image of the sun, image acquisition module attitude calculation, and calculation of the angle deviation between the heliostat mirror and the image acquisition module.

[0009] The beneficial effects of this invention are:

[0010] (1) The online calibration method of the image acquisition module used in this invention can be performed in an outdoor environment, which can ensure the efficiency of the generation and installation of the heliostat;

[0011] (2) The present invention achieves online accurate calibration of the image acquisition module by using the image coordinates of the center of the solar image over a certain period of time. The calibration process is simple and easy to operate.

[0012] (3) The online calibration method of the image acquisition module of the present invention can realize the parallel calibration of multiple heliostats and has high calibration efficiency. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the online calibration method of the present invention. Detailed Implementation

[0014] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0015] Example

[0016] like Figure 1 As shown, an online calibration method for an image acquisition module of a heliostat control system includes a mirror attitude measurement device 1 and a computing device 2.

[0017] The mirror attitude measurement device 1 is used to measure the three-dimensional coordinates, latitude, longitude and altitude information of the corner points of the heliostat mirror. It can be a total station or other surveying equipment, or a positioning device based on real-time dynamic carrier phase differential technology (RTK) or differential global positioning system (DGPS).

[0018] The computing device 2 is used for mirror attitude calculation, controlling the image acquisition module to acquire images, saving images, identifying the coordinates of the center image of the sun, image acquisition module attitude calculation, and calculation of the angular deviation between the heliostat mirror and the image acquisition module. The computing device 2 acquires data from the mirror attitude measurement device 1 and the image acquisition module via wireless or wired means.

[0019] Specifically, an online calibration method for an image acquisition module of a heliostat control system includes the following steps:

[0020] (1) The heliostat is installed and its attitude is fixed. The field of view of the image acquisition module is in the same direction as the heliostat's reflecting surface. The image acquisition module is in normal working condition.

[0021] (2) Establish a mirror field coordinate system with the center of the mirror field as the origin, where the X-axis is parallel to the due south direction, the Y-axis is parallel to the due east direction, and the Z-axis is perpendicular to the horizontal plane formed by the X-axis and Y-axis and points to the sky;

[0022] (3) Measure the relevant information of n (n≥4) corner points of the heliostat using a mirror attitude measurement device;

[0023] If the mirror attitude measurement device is a total station or other surveying equipment, then the three-dimensional coordinate information of n corner points of the heliostat can be obtained. Where x represents the X-axis component of the three-dimensional mirror field coordinate system, y represents the Y-axis component of the three-dimensional mirror field coordinate system, z represents the Z-axis component of the three-dimensional mirror field coordinate system, n represents the corner point number, and hnum represents the heliostat number.

[0024] If the mirror attitude measurement device is a positioning device such as RTK or differential GPS, then the positioning information of the n corner points of the heliostat... Where lon represents longitude data, lat represents latitude data, and alt represents altitude data;

[0025] (4) The computing device calculates the three-dimensional coordinate information of n corner points. or location information Fit the normal vector [ABC] of the mirror plane of the heliostat numbered hnum. hnum Then, the normal vector of the mirror plane [ABC] is... hnum Decomposed into azimuth angle Az about the Z-axis hnum and the pitch angle At about the Y-axis hnum ;

[0026] Where A represents the X-axis component of the mirror plane normal vector in the mirror field coordinate system, B represents the Y-axis component of the mirror plane normal vector in the mirror field coordinate system, and C represents the Z-axis component of the mirror plane normal vector in the mirror field coordinate system.

[0027] (5) The computing device controls the image acquisition module to acquire solar images at regular time intervals, obtaining a sequence of solar image center coordinate data, where the solar image center coordinate data at time t is... Simultaneously, the computing device calculates the solar incident vector [rx ry rz] based on the acquisition time t and the solar motion model. t ;

[0028] In the formula, u represents the column coordinate of the image, v represents the row coordinate of the image, rx represents the X-axis component of the solar incident vector mirror field coordinate system, ry represents the Y-axis component of the solar incident vector mirror field coordinate system, and rz represents the Z-axis component of the solar incident vector mirror field coordinate system.

[0029] (6) The calculation device uses the solar incidence vector data [rx ry rz] from all acquisition times. t and solar image center coordinate data The optical axis vector of the image acquisition module is calculated using the least squares method.

[0030] [cx cy cz] hnum Then, the optical axis vector [cx cy cz] hnum Decomposed into azimuth angle CAz around the Z-axis hnum and pitch angle CAt around the Y-axis hnum ;

[0031] In the formula, cx represents the X-axis component of the optical axis vector mirror field coordinate system, cy represents the Y-axis component of the optical axis vector mirror field coordinate system, and cz represents the Z-axis component of the optical axis vector mirror field coordinate system.

[0032] (7) The calculation module calculates the angular deviation between the heliostat mirror and the image acquisition module:

[0033]

[0034] In the formula dAz hnum dAt represents the azimuth deviation around the Z-axis. hnum Pitch angle deviation around the Y-axis;

[0035] (8) The calculation module saves the calibration results to the control system of the heliostat numbered hnum, and completes the online calibration of the image acquisition module of the single heliostat control system.

[0036] (9) All heliostats to be calibrated shall complete the calibration operation independently according to (1)-(8) above.

Claims

1. A method for online calibration of an image acquisition module in a heliostat control system, characterized in that, The process employs mirror attitude measurement and calculation equipment, specifically including the following steps: (1) The heliostat is installed and its attitude is fixed. The field of view of the image acquisition module is in the same direction as the heliostat's reflecting surface. The image acquisition module is in normal working condition. (2) Establish a mirror field coordinate system with the center of the mirror field as the origin, where the X-axis is parallel to the due south direction, the Y-axis is parallel to the due east direction, and the Z-axis is perpendicular to the horizontal plane formed by the X-axis and Y-axis and points to the sky; (3) Measure the relevant information of n corner points of the heliostat using a mirror attitude measurement device, where n≥4; (4) The calculation device fits the normal vector [ABC] of the mirror plane of the heliostat numbered hnum based on the three-dimensional coordinate information or positioning information of the n corner points. hnum Then, the normal vector of the mirror plane [ABC] is... hnum Decomposed into azimuth angle Az about the Z-axis hnum and the pitch angle At around the Y-axis hnum ; Where A represents the X-axis component of the mirror plane normal vector in the mirror field coordinate system, B represents the Y-axis component of the mirror plane normal vector in the mirror field coordinate system, and C represents the Z-axis component of the mirror plane normal vector in the mirror field coordinate system. (5) The computing device controls the image acquisition module to acquire solar images at regular time intervals, obtaining a sequence of solar image center coordinate data, where the solar image center coordinate data at time t is... Simultaneously, the computing device calculates the solar incident vector [rx ry rz] based on the acquisition time t and the solar motion model. t ; In the formula, u represents the column coordinate of the image, v represents the row coordinate of the image, rx represents the X-axis component of the solar incident vector mirror field coordinate system, ry represents the Y-axis component of the solar incident vector mirror field coordinate system, and rz represents the Z-axis component of the solar incident vector mirror field coordinate system. (6) The calculation device uses the solar incidence vector data [rx ry rz] from all acquisition times. t and solar image center coordinate data The optical axis vector of the image acquisition module is calculated using the least squares method. [cx cy cz] hnum Then, the optical axis vector [cx cy cz] hnum Decomposed into azimuth angle CAz around the Z-axis hnum and pitch angle CAt around the Y-axis hnum ; In the formula, cx represents the X-axis component of the optical axis vector mirror field coordinate system, cy represents the Y-axis component of the optical axis vector mirror field coordinate system, and cz represents the Z-axis component of the optical axis vector mirror field coordinate system. (7) The calculation module calculates the angular deviation between the heliostat mirror and the image acquisition module: In the formula dAz hnum dAt represents the azimuth deviation around the Z-axis. hnum Pitch angle deviation around the Y-axis; (8) The calculation module saves the calibration results to the control system of the heliostat numbered hnum, and completes the online calibration of the image acquisition module of the single heliostat control system. (9) All heliostats to be calibrated shall complete the calibration operation independently according to (1)-(8) above.

2. The online calibration method for the image acquisition module of the heliostat control system according to claim 1, characterized in that: If the mirror attitude measurement device in (3) is a total station, then the three-dimensional coordinate information of n corner points of the heliostat can be obtained. Where x represents the X-axis component of the three-dimensional mirror field coordinate system, y represents the Y-axis component of the three-dimensional mirror field coordinate system, z represents the Z-axis component of the three-dimensional mirror field coordinate system, n represents the corner point number, and hnum represents the heliostat number.

3. The online calibration method for the image acquisition module of the heliostat control system according to claim 1, characterized in that: The mirror attitude measurement device in (3) obtains the positioning information of n corner points of the heliostat based on real-time dynamic carrier phase differential technology or differential global positioning system. Where lon represents longitude data, lat represents latitude data, and alt represents altitude data.

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