A heliostat back plate flatness detection system and detection method

Abstract

The invention provides a heliostat back plate flatness detection system and a detection method thereof, comprising a mechanical arm, which is arranged at the center of the detection system, and a gripper is arranged at the output end of the mechanical arm to grab and move the heliostat back plate; a loading rack, which is arranged at the input end of the detection system, and the mechanical arm grabs the heliostat back plate from the loading rack; a detection rack, which is provided with a plurality of through holes, and at the through holes of the detection rack, a plurality of cameras are arranged on the back of the detection rack, the mechanical arm grabs the heliostat back plate and places it on the detection rack, the cameras take pictures from the through holes, and the flatness of the heliostat back plate is detected by a flatness detection module; a conveyor belt, which is the first output end of the detection system, and the mechanical arm transports the heliostat back plate that has passed the detection to the conveyor belt; and a recovery rack, which is the second output end of the detection system, and the mechanical arm transports the heliostat back plate that has not passed the detection to the recovery rack, thereby realizing automatic detection and screening of the heliostat back plate.

Description

Technical Field

[0001] The present invention relates to the technical field of heliostat processing, and in particular to a heliostat back plate flatness detection system and a detection method thereof. Background Art

[0002] During the fixing process of the heliostat mirror, a back plate is usually required to fix the mirror. After the heliostat back plate is produced, it needs to be transported from the factory to the mirror factory and glued and assembled to the mirror. During the production or transportation of the back plate, the heliostat back plate may be deformed due to collision. The flatness of the heliostat back plate is crucial to the overall performance of the heliostat. A flat back plate can ensure that the mirror reflection performance of the heliostat is uniform and consistent, thereby improving the solar energy collection efficiency. Therefore, the flatness of the heliostat back plate needs to be tested before the back plate of the heliostat is glued to the mirror. Currently, the flatness of the heliostat back plate is tested manually, with low efficiency and poor accuracy. The detection efficiency and quality can no longer match the increasing scale of the mirror factory. Summary of the invention

[0003] In order to solve the deficiencies in the prior art, a first object of the present invention is to provide a system for detecting the flatness of a heliostat back plate. Another object of the present invention is to provide a method for detecting the flatness of a heliostat back plate.

[0004] The heliostat back plate flatness detection system includes a mechanical arm, which is arranged at the center of the detection system, and a gripper is arranged at the output end of the mechanical arm to grab and move the heliostat back plate;

[0005] A loading rack, wherein the loading rack is arranged at the input end of the detection system, and a mechanical arm grabs the heliostat back plate from the loading rack;

[0006] A detection frame, wherein a plurality of through holes are arranged on the detection frame, and a plurality of cameras are arranged on the back of the detection frame at the through holes of the detection frame, and a mechanical arm grabs the heliostat back plate and places it on the detection frame, and the camera takes pictures from the through holes, and the flatness of the heliostat back plate is detected by a flatness detection system;

[0007] A conveyor belt, which is a first output end of the detection system, and the mechanical arm transports the heliostat back plate that has passed the detection to the conveyor belt;

[0008] The recovery rack is the second output end of the detection system, and the mechanical arm transports the heliostat back plate that fails the detection to the recovery rack.

[0009] Specifically, the gripper includes a gripper fixing plate and two gripping mechanisms symmetrically arranged in the gripper fixing plate, the gripping mechanism includes a gripping cylinder, a first hinged frame is arranged on the back side of the gripper fixing plate, the fixed end of the gripping cylinder is hinged in the gripper fixing plate, a clamping rod is hinged on the piston rod of the cylinder, a first through hole is arranged in the gripper fixing plate, the clamping rod passes through the first through hole, a second hinged frame is arranged at the first through hole, the clamping rod is hinged to the second hinged frame, an upper clamping part is arranged at the end of the clamping rod, a lower clamping part is arranged at the edge of the first through hole, a plug-in column is arranged in the lower clamping part, a second through hole is arranged in the gripper fixing plate, and a first sensor is arranged in the second through hole

[0010] Specifically, the loading rack includes a loading rack body, conveyor belts are arranged on both sides of the loading rack body, a loading auxiliary mechanism for loading the heliostat back plate from a fixed point is arranged at the entrance of the loading rack body, and a positioning mechanism for adjusting and fixing the position of the heliostat back plate is arranged at the exit of the loading rack body.

[0011] Specifically, the feeding auxiliary mechanism includes a lifting cylinder and a feeding plate installed on the lifting cylinder, the positioning mechanism includes a cylinder fixing plate and four side cylinders installed on the cylinder fixing plate, the rotating axis of the side cylinder is provided with a rotating frame, and a protrusion is provided on the rotating frame.

[0012] Specifically, a second sensor, a third sensor and a fourth sensor are provided on one side of the loading rack body, the second sensor is provided at the loading auxiliary mechanism, below the installation position of the heliostat back plate; the third sensor is provided between the positioning mechanism and the loading auxiliary mechanism; the third sensor is provided at the positioning mechanism, below the grabbing position of the heliostat back plate.

[0013] Specifically, a plurality of clamping plates are provided on the detection frame, and arc-shaped clamping grooves are provided in the clamping plates.

[0014] Specifically, a scanner is provided in the detection frame, and the scanner scans the heliostat back plate and records the information of the heliostat back plate.

[0015] Specifically, the flatness detection module includes an image acquisition module, a data processing module and an output module. The image acquisition module uses a camera to acquire images and outputs the images to the data processing module. The data processing module performs data processing and uses a modified corner point algorithm to select corner points. The data processing module calculates the flatness of the acquired corner point coordinates through the Lagrange multiplier method, and determines whether it is qualified based on the calculated flatness and the designed threshold. The output module feeds back the data processing results to the display system for visual display.

[0016] Specifically, the recovery frame includes a recovery frame body, a plurality of parallel mounting frames are arranged at the front end of the frame body, a support arm is arranged on one side of the mounting frame, a transverse limit groove is arranged in the mounting frame, a longitudinal limit groove is arranged in the support arm, and a support rod is arranged in the mounting frame on the same side of the support arm, a fifth sensor is installed on the support rod, and the fifth sensor is arranged below the back plate of the heliostat.

[0017] The present invention also provides a method for detecting the flatness of a heliostat back plate, comprising:

[0018] S1: placing the heliostat back plate on the loading tray, and the heliostat back plate is moved by the conveyor belt and fixed at the loading point;

[0019] S2: The robot moves to the loading point, grabs the heliostat backboard, and keeps grabbing, moving the heliostat backboard from the loading point to the inspection point;

[0020] S3: The camera takes a photo of the heliostat backplane and pre-processes the photo;

[0021] S4: Corner point selection is performed using a corner point algorithm, and distance constraints are added so that a sufficient number of corner points can be adaptively detected to represent the features of the image;

[0022] S5: The obtained corner point coordinates are used to calculate the flatness through the Lagrange multiplier method, and whether the flatness is qualified is determined according to the calculated flatness and the designed threshold;

[0023] S6: If the flatness of the backplane is qualified, execute S7; if the flatness of the backplane is unqualified, execute S8;

[0024] S7: The robotic arm moves the heliostat back plate to the conveyor belt and places the back plate on the conveyor belt;

[0025] S8: The robotic arm moves the heliostat back plate to the recovery rack, determines an empty position of the recovery rack, and places the heliostat back plate at the empty position of the recovery rack;

[0026] S9: The robot arm returns to its original position and repeats the above operation.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention provides a heliostat back plate flatness detection system and a detection method thereof. The detection system automatically detects heliostat back plates to be assembled through a flatness detection module according to the flatness of the heliostat back plates, and screens out defective back plates therefrom. The heliostat back plate detection system realizes automatic flatness detection of the heliostat back plates, significantly improves detection efficiency, and reduces labor intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of the detection system of the present invention;

[0030] Figure 2 This is a schematic diagram of the structure of the mechanical arm of the present invention;

[0031] Figure 3 This is a schematic diagram of the front structure of the robot arm gripper of the present invention;

[0032] Figure 4 This is a schematic diagram of the back structure of the robot arm gripper of the present invention;

[0033] Figure 5 A top view of the gripper of the mechanical arm of the present invention;

[0034] Figure 6 This is a schematic diagram of the overall structure of the loading rack of the present invention;

[0035] Figure 7 This is an enlarged view of part A of the present invention;

[0036] Figure 8 This is a schematic diagram of the structure of the feeding auxiliary mechanism of the present invention.

[0037] Fig. 9 It is a schematic diagram of the positioning mechanism structure of the present invention;

[0038] Fig.10 It is a schematic diagram of the internal structure of the side posture cylinder of the present invention;

[0039] Fig.11 It is a schematic diagram of the structure of the detection frame of the present invention;

[0040] Fig.12 It is a schematic diagram of the recovery rack mechanism of the present invention;

[0041] Fig.13 This is a schematic diagram of the heliostat back plate structure of the present invention.

[0042] Figure numerals: 1, mechanical arm; 11, gripper; 12, joint; 13, gripper fixing plate; 131, first articulated frame; 132, second articulated frame; 133, first through hole; 134, slot hole; 135, second through hole; 14, gripping mechanism; 141, gripping cylinder; 142, fork head; 143, U-shaped plate; 144, clamping rod; 145, upper clamping part; 15, lower clamping part; 16, plug-in column; 17, First sensor; 171, sensor fixing plate; 2, feeding rack; 21, feeding rack frame; 211, first fixing plate; 212, second fixing plate; 213, third fixing plate; 214, first angle code; 215, second angle code; 216, third angle code; 217, second sensor; 218, third sensor; 219, fourth sensor; 22, conveyor belt; 221, motor; 23, feeding auxiliary mechanism; 231 , lifting cylinder; 232, loading plate; 233, loading plate; 234, positioning frame; 24, positioning mechanism; 241, cylinder fixing plate; 242, side cylinder; 2421, shell; 2422, rack; 2423, gear; 2424, rotating shaft; 2425, rotating frame; 2426, bump; 243, fourth angle code; 244, fixing frame; 245, connecting plate; 25, foot switch; 3, detection frame; 3 1. Bottom plate; 32. Detection frame body; 33. Cushion block; 34. Snap-in plate; 35. Slot; 36. Detection hole; 4. Conveyor belt; 5. Recovery frame; 51. Recovery frame body; 52. Mounting frame; 521. Horizontal limit groove; 522. Support part; 53. Support arm; 531. Longitudinal limit groove; 54. Support rod; 55. Fifth sensor; 6. Heliostat back plate; 61. Mounting plate; 62. Adhesive plate; 63. Plug hole. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The specific implementation of the present invention is described in detail below in combination with specific embodiments.

[0044] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connection" and "setting" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0045] like Figure 1-Figure 13 As shown, a heliostat back plate flatness detection system comprises a robot arm 1, with a loading rack 2, a conveyor belt 4, a detection rack 3 and a recovery rack 5 arranged in sequence around the robot arm 1, and a gripper 11 is arranged at the output end of the robot arm 1, the gripper 11 grabs the heliostat back plate 6 from the loading rack 2, moves the heliostat back plate 6 to the detection rack 3 to detect the flatness of the heliostat, if the flatness of the heliostat back plate 6 is detected to be normal, the robot arm 1 puts the heliostat back plate 6 into the conveyor belt 4, if the flatness of the back plate fails to pass the detection, the robot arm 1 puts the heliostat back plate 6 into the recovery rack 5 to recover the heliostat back plate 6.

[0046] The heliostat back plate 6 includes a plate body, two mounting plates 61 are arranged at the center of the plate body, a plug hole 63 is arranged in the mounting plate 61, the mounting plate 61 is a gripping and positioning position of the heliostat back plate 6, 12 adhesive plates 62 are arranged on the plate body, and the mirror surface is pasted on the adhesive plates 62. The flatness of the entire heliostat back plate 6 is detected by detecting the flatness of the adhesive plates 62.

[0047] like Figure 2-Figure 5 As shown, the robot arm 1 is arranged at the center position of the detection system, and a joint 12 is arranged at the end of the robot arm 1. The joint 12 is connected to the back side of the gripper 11. The gripper 11 includes a gripper fixing plate 13 and two gripping mechanisms 14 symmetrically arranged in the gripper fixing plate 13. The joint 12 is fixedly installed in the center of the gripper fixing plate 13 by bolts.

[0048] The grabbing mechanism 14 is driven by a grabbing cylinder 141. A U-shaped plate 143 is fixedly installed at the fixed end of the grabbing cylinder 141 by bolts. First hinged frames 131 are respectively provided at both ends of the grabbing fixing plate 13. The first hinged frame 131 is fixedly installed on the back of the grabbing fixing plate 13. The U-shaped plate 143 is hinged in the first hinged frame 131. A fork head 142 is provided at the end of the piston rod of the grabbing cylinder 141. The clamping rod 144 is hinged in the fork head 142. In the grabbing fixing plate 13, first through holes 133 are provided on both sides of the joint 12. The clamping rod 144 passes through the first through hole 133 and is hinged to the second hinged frame 132 provided at the first through hole 133. The second hinged frame 132 is U-shaped and is installed in the grabbing fixing plate 13 by bolts. An upper clamping portion 145 is provided at the end of the clamping rod 144, and the upper clamping portion 145 is fixedly connected to the clamping rod 144 by bolts. A lower clamping portion 15 is provided at the edge of the first through hole 133, and the lower clamping portion 15 is fixedly installed in the gripper fixing plate 13. The upper clamping portion 145 and the lower clamping portion 15 clamp the mounting plate 61 from both sides of the mounting plate 61. A plug-in column 16 is provided at the center of the lower clamping portion 15, and the position of the plug-in column 16 matches the position of the plug-in hole 63 of the mounting plate 61. When grasping, the plug-in column 16 is inserted into the plug-in hole 63 of the mounting plate 61 to limit the heliostat back plate 6. A slot hole 134 is provided below the lower clamping portion 15, and when the grasping cylinder 141 contracts, the clamping rod 144 is placed in the slot hole 134. Protrusions are respectively provided on both sides of the upper clamping portion 145 and the lower clamping portion 15 , and the protrusions abut against both sides of the mounting plate 61 during grasping.

[0049] When not grasping, the grasping cylinder 141 is in a retracted state, and the piston rod of the grasping cylinder 141 pulls the clamping rod 144, so that the upper clamping part 145 and the lower clamping part 15 are staggered at an angle; when grasping the heliostat back plate 6, the plug-in column 16 is inserted into the plug-in hole 63, the grasping cylinder 141 extends, and the clamping rod 144 rotates around the second hinge frame 132 as the axis, so that the upper clamping part 145 is placed above the lower clamping part 15, and the protrusions of the upper clamping part 145 and the lower clamping part 15 are respectively abutted against the two sides of the mounting plate 61.

[0050] At the mounting plate 61 of the heliostat back plate 6, a second through hole 135 is provided in the gripper fixing plate 13, and a first sensor 17 is provided in the second through hole 135. A sensor fixing plate 171 installed in the gripper fixing plate 13 is provided at the second through hole 135, and the first sensor 17 passes through the second through hole 135 and is installed in the sensor fixing plate 171. A controller is also provided in the robot arm 1, and the controller controls the grasping and moving of the heliostat back plate 6 by controlling the movement of the robot arm 1 and the extension and contraction of the grasping cylinder 141. The robot arm 1 moves to the grasping position, and the first sensor 17 determines whether there is material at the position. When it is confirmed that there is material at the position, that is, the plug-in column 16 is inserted into the plug-in hole 63 of the mounting plate 61, the first sensor 17 sends a signal to the controller, and the controller controls the grasping cylinder 141 to extend to grasp the heliostat back plate 6. The first sensor 17 detects whether there is a heliostat back plate 6 at the grasping position and whether the heliostat back plate 6 is grasped successfully, and feeds back a signal to the controller of the robot arm 1 . After the grasping is successful, the robot arm 1 rotates and moves the heliostat back plate 6 to the detection frame 3 .

[0051] The robot arm 1 grabs the heliostat back plate 6 from the loading rack 2. The loading rack 2 includes a loading rack frame 22. A conveyor belt 22 is arranged on the loading rack frame 22. A loading auxiliary mechanism 23 is arranged at the entrance of the loading rack frame 22 along the movement direction of the conveyor belt 22 to locate the loading position of the heliostat back plate 6. A positioning mechanism 24 is arranged at the exit of the loading rack frame 22. A loading point is arranged at the positioning mechanism 24. The positioning mechanism 24 adjusts and fixes the position of the heliostat back plate 6, so that the robot arm 1 accurately clamps the heliostat back plate 6 from the loading point.

[0052] The conveyor belt 22 is arranged on both sides of the loading rack body 22. The conveyor belt 22 is a chain conveyor belt 22, and the conveyor belt 22 is driven by a motor 221. A first fixed plate 211 is arranged at the entrance of the loading rack body 22, and first angle codes 214 are arranged on both sides of the first fixed plate 211. One side of the first angle code 214 is fixedly connected to the first fixed plate 211, and the other side is fixedly connected to the body, so that the first fixed plate 211 is fixedly installed in the body. The feeding auxiliary mechanism 23 is installed in the first fixed plate 211, and the feeding auxiliary mechanism 23 includes a lifting cylinder 231 and a feeding plate 232 installed on the piston rod of the lifting cylinder 231. The side wall of the lifting cylinder 231 is installed on the first fixed plate 211, and the piston rod of the lifting cylinder 231 is vertically arranged upward. The loading tray 232 includes a loading plate 233 and positioning frames 234 arranged on both sides of the loading plate 233. A groove is arranged in the positioning frame 234. The shape of the groove matches the shape of the mounting plate 61. The heliostat back plate 6 can be placed on the loading tray 232, and the mounting plate 61 is engaged in the groove. When the piston rod of the lifting cylinder 231 is extended, the height of the loading tray 232 is higher than the height of the conveyor belt 22. When the piston rod of the lifting cylinder 231 is retracted, the height of the loading tray 232 is lower than the height of the conveyor belt 22, and the heliostat back plate 6 falls on the conveyor belt 22, so that the heliostat back plate 6 is transported from a fixed point through the conveyor belt 22.

[0053] A second sensor 217 is provided beside the conveyor belt 22 on one side of the loading rack frame 22. When the heliostat back plate 6 is located on the loading tray 232, the second sensor 217 is provided at the loading auxiliary mechanism 23, located below the installation position of the heliostat back plate 6. When the heliostat back plate 6 falls onto the transmission belt, the second sensor 217 can detect whether the heliostat back plate 6 is installed in place. A foot switch 25 is provided on the outside of the frame, and the foot switch 25 is used to start the loading auxiliary mechanism 23. After the staff has placed the heliostat back plate 6 steadily, they leave the equipment and start the foot switch 25, and the piston rod of the lifting cylinder 231 contracts. When the heliostat back plate 6 is placed in place and falls onto the conveyor belt 22, when the second sensor 217 detects that the heliostat back plate 6 is in place, the conveyor belt 22 is started to transport the heliostat back plate 6 to the end of the frame; when the second sensor 217 does not detect the heliostat back plate 6, an alarm is issued to inform the staff. The feeding auxiliary mechanism 23 is used to ensure that the heliostat back plate 6 is transported from a fixed point, and the accuracy of the movement of the heliostat back plate 6 is ensured. The motor 221 is started to drive the conveyor belt 22 to move a certain distance, and the heliostat back plate 6 placed on the conveyor belt 22 is transported to the top of the positioning mechanism 24. After the heliostat back plate 6 leaves, the feeding auxiliary mechanism 23 returns to its position.

[0054] When the heliostat back plate 6 moves on the conveyor belt 22, after the conveyor belt 22 stops, the position of the heliostat back plate 6 will be offset from the preset position due to inertia. When the mechanical arm 1 grabs the heliostat back plate 6, the plug-in column 16 cannot be accurately inserted into the plug-in hole 63, which may easily cause damage to the heliostat back plate 6 or the mechanical arm 1. In order to improve the accuracy of grabbing the heliostat back plate 6, a positioning mechanism 24 is designed at the end of the loading rack body 22 to adjust and fix the position of the heliostat back plate 6. A second fixing plate 212 and a third fixing plate 213 are provided at the exit of the material loading rack body 22, and a second angle code 215 and a third angle code 216 are provided on both sides of the second fixing plate 212 and the third fixing plate 213, respectively. One side of the second angle code 215 is fixedly connected to the second fixing plate 212, and the other side is fixedly connected to the material loading rack body 22. One side of the third angle code 216 is fixedly connected to the third fixing plate 213, and the other side is fixedly connected to the material loading rack body 22, so that the second fixing plate 212 and the third fixing plate 213 are fixedly installed in the material loading rack body 22. The positioning mechanism 24 is provided between the second fixing plate 212 and the third fixing plate 213, and includes a cylinder fixing plate 241 and four side posture cylinders 242 installed on the cylinder fixing plate 241. On both sides of the cylinder fixing plate 241, the fourth angle code 243 is fixedly connected to the side walls of the second fixing plate 212 and the third fixing plate 213. A fixing frame 244 is installed on the cylinder fixing plate 241, a connecting plate 245 is installed on the fixing frame 244, and a side posture cylinder 242 is installed on the connecting plate 245. The side posture cylinder 242 forms an angle of degrees with the second fixing plate 212 or the third fixing plate 213 in the horizontal direction. A rotating frame 2425 is provided on the rotating shaft 2424 of the side posture cylinder 242. The rotating frame 2425 rotates around the rotating shaft 2424 of the side posture cylinder 242. A protrusion 2426 is provided at the front end of the rotating frame 2425. The protrusion 2426 abuts against the corner position of the mounting plate 61 of the heliostat back plate 6. Two side posture cylinders 242 on the same side clamp one mounting plate 61, and the four side posture cylinders 242 jointly adjust and fix the position of the heliostat back plate 6.

[0055] The side posture cylinder 242 can be a hinged side posture cylinder 242 or a rack side posture cylinder 242. This embodiment uses a rack 2422 side posture cylinder 242 to illustrate the technical solution. As shown in the figure, the side posture cylinder 242 includes a cylinder body and a shell 2421 arranged above the cylinder body. The shell 2421 protects the side posture cylinder 242 structure. A rack 2422 is arranged at the upper part of the piston rod. A rotating shaft 2424 rotatably connected to the shell 2421 is arranged on one side of the rack 2422. A gear 2423 is arranged on the rotating shaft 2424. The gear 2423 is meshed with the rack 2422. A rotating frame 2425 is fixedly connected to both ends of the rotating shaft 2424. A bump 2426 is arranged at the front end of the rotating frame 2425. The gear 2423 is driven to rotate by the cylinder piston rod, so that the rotating frame 2425 rotates around the rotating shaft 2424 as the axis, so that the protrusion 2426 abuts against the corner position of the mounting plate 61 of the heliostat back plate 6.

[0056] A third sensor 218 is provided at the path position of the heliostat back plate 6, between the positioning mechanism 24 and the feeding auxiliary mechanism 23. The third sensor 218 detects the passing condition of the heliostat back plate 6 and detects whether the heliostat back plate 6 is transported to the positioning mechanism 24 using a transmission belt. A fourth sensor 219 is provided at the end of the feeding frame 22. When the heliostat back plate 6 is clamped by the positioning mechanism 24, the fourth sensor 219 is provided below the heliostat back plate 6 to detect whether the heliostat back plate 6 is in place. The third sensor 218 and the fourth sensor 219 are electrically connected to the controller of the robot 1. According to the detection results of the third sensor 218 and the fourth sensor 219, the robot 1 determines whether to grab the heliostat back plate 6. When the third sensor 218 detects that the heliostat back plate 6 passes and the fourth sensor 219 detects that the heliostat back plate 6 is in place, the heliostat back plate 6 is transported by the conveyor belt 22 and fixed at the grabbing position, the robot arm 1 grabs the heliostat back plate 6 and transports it to the detection frame 3, and detects the flatness of the heliostat back plate 6; when any of the third sensor 218 and the fourth sensor 219 does not detect the heliostat back plate 6, the heliostat back plate 6 may be offset during transportation or the staff directly transports the heliostat back plate 6 to the positioning mechanism 24 without the conveyor belt 22, and the controller sends a signal to inform the staff that the robot arm 1 does not grab the heliostat back plate 6. The third sensor 218 and the fourth sensor 219 are used for joint detection to prevent the robot arm 1 from forcibly grabbing the heliostat back plate 6 in the wrong position, causing further damage to the heliostat back plate 6 or the robot arm 1, and also to prevent the robot arm 1 from causing personal injury to the staff when grabbing the heliostat back plate 6, thereby avoiding the occurrence of production risks.

[0057] The robot arm 1 grabs the heliostat back plate 6 and moves to the detection point of the detection frame 3. The detection frame 3 includes a detection frame body 32 and a bottom plate 31 arranged on the detection frame body 32. The detection frame 3 detects the flatness of the adhesive plate 62 and the mounting plate 61. A plurality of snap-in plates 34 are arranged on the frame body, and the number of the snap-in plates 34 matches the number of the adhesive plates 62. The snap-in plates 34 are fixedly mounted on the frame body through cushion blocks 33. A circular arc-shaped snap-in groove 35 is arranged in the snap-in plate 34, and the shape of the snap-in groove 35 matches the shape of the heliostat back plate 6. A scanner is arranged in the detection frame 3, and a two-dimensional code is arranged on the heliostat back plate 6. The heliostat back plate 6 moves to the detection point, and the scanner scans the two-dimensional code and records the information of the heliostat back plate 6. A plurality of detection holes 36 are provided on the detection frame 3. The detection holes 36 are provided at the adhesive plate 62 and the mounting plate 61 when the heliostat back plate 6 is located at the detection point. A camera is provided at each scanning hole. The camera is fixedly mounted on the rear side of the bottom plate 31. The adhesive plate 62 and the mounting plate 61 are photographed from the detection holes 36. The flatness detection module detects the flatness of the heliostat back plate 6 according to the photographed photos.

[0058] A plurality of snap-in plates 34 perform preliminary inspection on the standard shape of the heliostat back plate 6. When the shape of the heliostat back plate 6 is standard, the adhesive plate 62 can be snapped into the snap-in plates 34. If the heliostat back plate 6 is deformed, it is difficult for the adhesive plate 62 to be completely snapped into the snap-in plates 34. The robot 1 directly moves the heliostat back plate 6 to the recovery rack 5. If the preliminary inspection is passed, the controller of the robot 1 sends a photo signal to the camera, and the camera takes a photo of the adhesive plate 62. The flatness of the heliostat back plate 6 is detected by the flatness detection module. The flatness detection module includes an image acquisition module, a data processing module and an output module. The image acquisition module uses the camera to acquire images and outputs the images to the data processing module. The data processing module performs data processing and selects corner points using the modified corner point algorithm. The data processing module calculates the flatness of the acquired corner point coordinates through the Lagrange multiplier method, and determines whether it is qualified according to the calculated flatness and the designed threshold. The output module feeds back the data processing results to the display system for visual display. When the flatness of the heliostat back plate 6 is qualified, the robot arm 1 moves the heliostat back plate 6 to the conveyor belt 22, and the conveyor belt 22 moves the heliostat back plate 6 to the next process; when the flatness of the heliostat back plate 6 is unqualified, the robot arm 1 moves the heliostat back plate 6 to the recovery rack 5 to store the heliostat back plate 6.

[0059] The recovery rack 5 may be one or more, including a recovery rack body 51, a plurality of parallel mounting racks 52 are arranged at the front end of the recovery rack body 51, a transverse limiting groove 521 for fixing the heliostat back plate 6 is arranged in the mounting rack 52, a support arm 53 is arranged on one side of the mounting rack 52, a longitudinal limiting groove 531 for fixing the heliostat back plate 6 is arranged in the support arm 53, and an oblique angle is arranged at the edges of the transverse limiting groove 521 and the longitudinal limiting groove 531 to facilitate the heliostat back plate 6 to be placed in the recovery rack. A support portion 522 is arranged at the front end of the mounting rack 52, and the height of the support portion 522 is flush with the height of the transverse limiting groove 521. The adjacent two sides of the heliostat back plate 6 are respectively engaged in the longitudinal limiting groove 531 and the transverse fiber groove to fix the heliostat back plate 6.

[0060] On the same side as the support arm 53, a support rod 54 is provided on the mounting frame 52, and a fifth sensor 55 is installed on the support rod 54. The fifth sensor 55 is provided below the heliostat back plate 6 to detect whether the heliostat back plate 6 is installed at the current position. When the robot 1 places the heliostat back plate 6 on the mounting frame 52, the fifth sensor 55 senses that the heliostat back plate 6 is placed at the position, and transmits the signal to the controller of the robot 1. When the robot 1 places the heliostat back plate 6, the controller sequentially determines whether there is a heliostat back plate 6 on the mounting frame 52 of each recovery frame 5, and sequentially places the heliostats in the mounting frame 52 at the vacant position.

[0061] The flatness detection method of the heliostat backplane is:

[0062] S1: placing the heliostat back plate 6 on the loading tray 232 , and the heliostat back plate 6 is moved to and fixed at the loading point via the conveyor belt 22 .

[0063] The staff puts the heliostat back plate 6 in the loading tray 232, away from the loading rack 2 and starts the foot switch 25, the piston rod of the lifting cylinder 231 is lowered, and the heliostat back plate 6 falls on the conveyor belt 22. The second sensor 217 detects the heliostat back plate 6 and starts the conveyor belt 22. The conveyor belt 22 runs for a distance and transports the heliostat back plate 6 to the end of the loading rack 2. After the heliostat is in place, the positioning mechanism 24 is started to adjust the position of the heliostat back plate 6 and clamp the heliostat back plate 6 to fix the position of the heliostat back plate 6. During the transportation process, it is detected by the third sensor 218 and after the transportation is in place, it is detected by the fourth sensor 219. After the detection is correct, a material picking signal is sent to the controller of the mechanical arm 1. When the third sensor 218 or the fourth sensor 219 does not detect the heliostat back plate 6, an alarm is sent to inform the staff, and the mechanical part does not grab the heliostat back plate 6.

[0064] The first sensor 17 , the second sensor 217 , the third sensor 218 , the fourth sensor 219 , and the fifth sensor 55 are proximity sensors.

[0065] S2: The robot arm 1 moves to the loading point, grabs the heliostat back plate 6, and keeps the grabbing state, and moves the heliostat back plate 6 from the loading point to the detection point.

[0066] The robot arm 1 moves to the loading point, the grabbing cylinder 141 is in a retracted state, the gripper fixing plate 13 is parallel to the heliostat back plate 6, the plug-in column 16 is aligned with the plug-in hole 63, the plug-in column 16 is inserted into the plug-in hole 63, and moves until the protrusion of the lower clamping part 15 abuts on the mounting plate 61 of the heliostat back plate 6, the first sensor 17 determines whether there is material at this position, and if it is determined that there is material, it sends an electrical signal to the controller, the controller controls the cylinder piston rod to extend, the clamping rod 144 rotates with the second hinge frame 132 as the axis, and the protrusion of the upper clamping part 145 abuts on the mounting plate 61, and the heliostat back plate 6 is grabbed through the cooperation of the plug-in column 16, the upper clamping part 145 and the lower clamping part 15, and the heliostat back plate 6 is moved by the robot arm 1, and the heliostat back plate 6 is grabbed and moved to the detection point of the detection frame 3.

[0067] S2.1: The detection frame 3 scans and records the information of the heliostat back plate 6 , and performs a preliminary screening of the heliostat back plate 6 .

[0068] The heliostat back plate 6 moves to the detection point, the scanner scans the QR code and records the information of the heliostat back plate 6, and the standard shape of the heliostat back plate 6 is preliminarily detected through multiple clamping plates 34. If the shape of the heliostat back plate 6 is not standard, the adhesive plate cannot be completely clamped in all the clamping plates 34, and the robot arm 1 cannot move the heliostat back plate 6 to the detection point. If it passes the preliminary screening, continue to execute S3, and if it fails the preliminary screening, execute S8 to recycle the heliostat back plate 6.

[0069] S3: The camera takes a photo of the heliostat back plate 6 and pre-processes the photo.

[0070] The world coordinate system is the absolute coordinate system of the objective three-dimensional space, also called the objective coordinate system. The position of the camera in the three-dimensional space is determined by establishing the world coordinate system. When the camera position is determined, the position of the target object in the three-dimensional space is also determined. The Zhang calibration method is used to calibrate the camera. The black and white grid calibration plate is moved 2 cm up and down and left and right to take pictures. The camera is calibrated and the image coordinates are converted into world coordinates.

[0071] S3.1: Noise removal, using Gaussian filtering or median filtering to reduce noise in the image;

[0072] S3.2: Grayscale, converting the color image into a grayscale image;

[0073] S3.3: Histogram equalization improves the contrast of the image, making feature points easier to detect.

[0074] S4: Corner point selection is performed using a corner point algorithm, with distance constraints added so that a sufficient number of corner points can be adaptively detected to represent the features of the image.

[0075] In step S4, a fixed window ω(x, y) is set to slide in any direction on the image, and the changes in the pixel grayscale values ​​in the window area before and after the sliding are compared. If there is a large grayscale change in any direction, it is considered that there is a corner point in the window.

[0076] The response function calculation method is improved in the corner point algorithm, and the distance constraint is added. The formula is as follows:

[0077]

[0078] N is the number of corner points currently calculated, λ1 and λ2 are eigenvalues, and k is a constant.

[0079] The steps for corner point selection are as follows:

[0080] S4.1: Compare the two eigenvalues ​​of the second-order matrix M, directly perform classification, and find the smaller eigenvalue of each pixel point and record it as the corner point response function R;

[0081]

[0082] In the formula, the fixed window ω(x,y), u,v are pixels, x,y are image coordinates, and all image files are two-dimensional planes; IX represents the gradient in the X direction, and IY represents the gradient in the Y direction;

[0083] S4.2: Arrange the corner point response functions R in descending order;

[0084] S4.3: Mark the pixels corresponding to the first 200 R values ​​as pre-selected corner points and traverse them in turn. If there are points marked as corner points in the four neighborhoods of the pre-selected corner points, compare the distance between the two points. If the distance is less than the minimum tolerance distance of d pixels, the current pixel point is discarded because the R value of the pixel point first determined as the corner point is larger and the corner point is more representative. Otherwise, the current pixel point is marked as a corner point.

[0085] S4.4: Experiments are conducted on the multispectral images acquired by the Q-band camera of the backplane flatness detection target image. The threshold is continuously adjusted and the results are compared. When the number of corner points is reduced to B, the motion estimation and image stabilization can still be completed well. At this time, if the number of corner points is further reduced, the image stabilization effect viewed by the human eye will be greatly weakened. Therefore, B is used as the reference value for the number of corner points when extracting corner points. When the number of true corner points is less than B, the number of pre-selected corner points is increased, and the true corner points are screened again.

[0086] From a statistical point of view, this application conducts experiments on 200 multispectral images collected by cameras of the target image of the flatness detection of the heliostat back plate 6, and continuously adjusts the threshold. The comparison results show that when the number of corner points is reduced to about 30, the motion estimation and image stabilization can still be completed well. At this time, if the number of corner points is further reduced, the image stabilization effect viewed by the human eye will be greatly weakened. Therefore, 30 is used as the reference value of the number of corner points when extracting corner points. When the number of true corner points is less than 30, the number of pre-selected corner points is increased, and the true corner points are screened again.

[0087] Invariance to 2D translation and rotation: The Harris corner detection algorithm is somewhat invariant to 2D translation and rotation. This means that when the image is translated or rotated on a 2D plane, the algorithm can still accurately detect the corners. This invariance makes the algorithm more reliable when processing images with different perspectives and orientations.

[0088] S5: Obtain the coordinates of the corner points, calculate the flatness through the Lagrange multiplier method, and judge whether it is qualified according to the calculated flatness and the designed threshold.

[0089] In step S5, the fitted plane equation is assumed to be:

[0090] ax+by+cz+d=0 (2-1)

[0091] The constraints are:

[0092] a 2 +b 2 +c 2 =1 (2-2)

[0093] The plane parameters a, b, c, and d are obtained. At this time, to make the obtained fitting plane optimal, the sum of the squares of the distances from the points to the plane is minimized, which satisfies:

[0094]

[0095] Where, d i =|ax i +by i +cz i +d|, is any point p in the point cloud data i (x i ,y i ,z i The distance to this plane; to make e→min, use the Lagrange multiplier method to solve the extreme value and get the function:

[0096]

[0097] First, take the partial derivatives of both sides of equation 2-4 with respect to d, and set the partial derivatives to zero, and we get:

[0098]

[0099] make Centroid but:

[0100] d i =|aΔx i +bΔy i +cΔz i |

[0101] (2-6)

[0102] Taking the partial derivatives of both sides of equation 2-4 with respect to a, b, and c, we get

[0103]

[0104] The above system of equations is formed into an eigenvalue equation:

[0105] Ax=λ3x (2-7)

[0106] In the formula,

[0107]

[0108] Solving the plane parameters a, b, c is to solve the matrix to obtain the eigenvalues ​​and eigenvectors. And because A is a 3rd-order real symmetric matrix, the formula for solving its eigenvalues ​​is:

[0109]

[0110] Under the constraint condition a 2 +b 2 +c 2 =1, we can get

[0111]

[0112] The minimum value of e is the minimum eigenvalue of matrix A. The corresponding eigenvector is the plane parameters a, b, and c. d can be obtained using the centroid.

[0113] a, b, c, d are all calculated, then the fitted plane equation ax+by+cz+d=0 is substituted into it and the result is calculated. Then the coordinates of each point are known, and the distance from the point to the plane is the result we want. e is the minimum value, and e is compared with the threshold. The threshold used in the project is 3mm.

[0114] S6: If the flatness of the backplane is qualified, execute S7; if the flatness of the backplane is unqualified, execute S8.

[0115] S7: the robot arm 1 moves the heliostat back plate 6 to the conveyor belt 4 and places the back plate on the conveyor belt 4 .

[0116] S8: the robot arm 1 moves the heliostat back plate 6 to the recovery rack 5 , determines an empty position of the recovery rack 5 , and places the heliostat back plate 6 at the empty position of the recovery rack 5 .

[0117] The robot arm 1 moves the heliostat back plate 6 to the recovery rack 5, and the controller of the robot arm 1 receives the material signal from the fifth sensor 55, and judges whether there is a heliostat back plate 6 in each mounting rack 52 in turn, and places the heliostat back plate 6 in the vacant position. When the heliostat back plate 6 is placed in all the mounting racks 52, the robot arm 1 does not perform the grabbing operation, and issues an alarm to inform the staff to take away the heliostat back plate 6 in time.

[0118] S9: Robot arm 1 returns to its original position and repeats the above operation.

[0119] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structural transformation made by using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A heliostat backplane flatness detection system, characterized in that: include: A mechanical arm (1), the mechanical arm (1) being arranged at the center of the detection system, and a gripper (11) being arranged at the output end of the mechanical arm (1) for gripping and moving the heliostat back plate (6); The gripper (11) comprises a gripper fixing plate (13) and two gripping mechanisms (14) symmetrically arranged in the gripper fixing plate (13), the gripping mechanism (14) comprising a gripping cylinder (141), a first hinge frame (131) being arranged on the back of the gripper fixing plate (13), a fixed end of the gripping cylinder (141) being hinged in the gripper fixing plate (13), a clamping rod (144) being hinged on the piston rod of the cylinder, a first through hole (133) being arranged in the gripper fixing plate (13), the clamping rod (144) passing through the first through hole (133) A through hole (133), a second hinge frame (132) is arranged at the first through hole (133), the clamping rod (144) is hinged to the second hinge frame (132), an upper clamping portion (145) is arranged at the end of the clamping rod (144), a lower clamping portion (15) is arranged at the edge of the first through hole (133), a plug-in column (16) is arranged in the lower clamping portion (15), a second through hole (135) is arranged in the gripper fixing plate (13), and a first sensor (17) is arranged in the second through hole (135); A loading rack (2), the loading rack (2) being arranged at the input end of the detection system, and a mechanical arm grabs a heliostat back plate (6) from the loading rack (2); The loading rack (2) comprises a loading rack frame (21), conveyor belts (22) are arranged on both sides of the loading rack frame (21), a loading auxiliary mechanism (23) for loading the heliostat back plate (6) from a fixed point is arranged at the entrance of the loading rack frame (21), and a positioning mechanism (24) for adjusting and fixing the position of the heliostat back plate (6) is arranged at the exit of the loading rack frame (21); The loading auxiliary mechanism (23) comprises a lifting cylinder (231) and a loading plate (232) mounted on the lifting cylinder (231); the positioning mechanism (24) comprises a cylinder fixing plate (241) and four side posture cylinders (242) mounted on the cylinder fixing plate (241); the rotating shaft (2424) of the side posture cylinder (242) is provided with a rotating frame (2425), and a bump (2426) is provided on the rotating frame (2425); A detection frame (3), wherein a plurality of through holes are arranged on the detection frame (3), and a plurality of cameras are arranged on the back of the detection frame (3) at the through holes of the detection frame (3); a mechanical arm (1) grabs a heliostat back plate (6) and places it on the detection frame (3); the camera takes a picture from the through holes, and the flatness of the heliostat back plate (6) is detected by a flatness detection module; A conveyor belt (4), the conveyor belt (4) being a first output end of the detection system, and the mechanical arm (1) transports the heliostat back plate (6) that has passed the detection to the conveyor belt (4); A recovery rack (5), the recovery rack (5) being a second output end of the detection system, and the mechanical arm (1) transports the heliostat back plate (6) that has not passed the detection to the recovery rack (5).

2. The heliostat backplane flatness detection system according to claim 1, characterized in that: A second sensor (217), a third sensor (218) and a fourth sensor (219) are arranged on one side of the loading rack body (21); the second sensor (217) is arranged at the loading auxiliary mechanism (23) and is located below the installation position of the heliostat back plate (6); the third sensor (218) is arranged between the positioning mechanism (24) and the loading auxiliary mechanism (23); the third sensor (218) is arranged at the positioning mechanism (24) and is located below the gripping position of the heliostat back plate (6).

3. The heliostat backplane flatness detection system according to claim 1, characterized in that: A plurality of clamping plates (34) are arranged on the detection frame (3), and arc-shaped clamping grooves (35) are arranged in the clamping plates (34).

4. The heliostat backplane flatness detection system according to claim 1, characterized in that: The detection frame (3) is provided with a scanner, which scans the heliostat back plate (6) and records the information of the heliostat back plate (6).

5. The heliostat backplane flatness detection system according to claim 1, characterized in that: The flatness detection module includes an image acquisition module, a data processing module and an output module. The image acquisition module uses a camera to acquire images and outputs the images to the data processing module. The data processing module performs data processing and uses a modified corner point algorithm to select corner points. The data processing module calculates the flatness of the acquired corner point coordinates through the Lagrange multiplier method, and determines whether it is qualified based on the calculated flatness and the designed threshold; the output module feeds back the data processing results to the display system for visual display.

6. The heliostat backplane flatness detection system according to claim 1, characterized in that: The recovery frame (5) comprises a recovery frame body (51), a plurality of parallel mounting frames (52) are arranged at the front end of the frame body, a support arm (53) is arranged on one side of the mounting frame (52), a transverse limit groove (521) is arranged in the mounting frame (52), a longitudinal limit groove (531) is arranged in the support arm (53), a support rod (54) is arranged in the mounting frame (52) on the same side as the support arm (53), a fifth sensor (55) is installed on the support rod (54), and the fifth sensor (55) is arranged below the heliostat back plate (6).

7. A method for detecting the flatness of a heliostat back plate, using the heliostat back plate flatness detection system according to any one of claims 1 to 6, characterized in that: include: S1: placing the heliostat back plate (6) on the loading plate (232), and the heliostat back plate (6) is moved via the conveyor belt (22) and fixed at the loading point; S2: the robot arm (1) moves to the loading point, grabs the heliostat back plate (6), and continues to maintain the grabbing state, and moves the heliostat back plate (6) from the loading point to the detection point; S3: The camera takes a picture of the heliostat back plate (6) and pre-processes the picture; S4: Corner point selection is performed using a corner point algorithm, and distance constraints are added so that a sufficient number of corner points can be adaptively detected to represent the features of the image; S5: The obtained corner point coordinates are used to calculate the flatness through the Lagrange multiplier method, and whether the flatness is qualified is determined according to the calculated flatness and the designed threshold; S6: If the flatness of the backplane is qualified, execute S7; if the flatness of the backplane is unqualified, execute S8; S7: the mechanical arm (1) moves the heliostat back plate (6) to the conveyor belt (4), and places the back plate on the conveyor belt (4); S8: the mechanical arm (1) moves the heliostat back plate (6) to the recovery rack (5), determines an empty position of the recovery rack (5), and places the heliostat back plate (6) at the empty position of the recovery rack (5); S9: The robot arm (1) returns to its original position and repeats the above operation.

Images