Blade detection method and device based on laser radar, equipment and storage medium

Abstract

The invention provides a blade detection method and device based on a laser radar, equipment and a storage medium, and the method comprises the steps: storing a plurality of continuously detected first candidate values in a first sequence when a real-time distance measurement value is detected to be smaller than a preset reference distance value; and when the detected real-time distance measurement value is equal to the reference distance value, the first detection duration of the first sequence is within a preset duration interval, and the difference value between the first candidate values is smaller than or equal to a preset difference threshold value, determining the first detected object corresponding to the first sequence as the paddle. According to the technical scheme provided by the embodiment of the invention, as the staying durations of the paddle and the natural object in the detection range of the laser radar are greatly different, the first detection duration can be compared by utilizing the preset duration interval, so that the paddle and the natural object are preliminarily distinguished, and the paddle surface is generally a flat surface; and the difference value of the first candidate value is small, so that the paddle and the natural object are accurately distinguished, and the paddle detection accuracy is improved.

Description

Technical Field

[0001] The present invention relates to the field of laser radar technology, and in particular to a laser radar-based blade detection method, device, equipment, and storage medium. Background Art

[0002] At present, wind power generation is one of the common clean energy sources. Common wind power generation equipment includes a tower, a cabin and blades. The cabin is installed at the top of the tower, and the power generation equipment is installed in the cabin. The blades are installed at one end of the cabin and rotate under the action of wind to drive the power generation equipment in the cabin to generate electricity. In the case of strong winds or after being used for a long time, the rotating surface of the blades may deviate vertically to a certain extent. It is necessary to promptly detect the clearance distance between the blades and the tower to avoid the blades from deviating too much and sweeping the tower and causing damage.

[0003] With the development of LiDAR technology, related technologies will install LiDAR in the cabin to detect distance by tilting downward. The detection range of LiDAR is between the propeller blade and the tower. During the normal operation of the propeller blade, the distance detected by LiDAR is the distance to the ground. When the propeller blade deviates and approaches the tower, it enters the detection range of LiDAR, causing the detection value of LiDAR to change, thereby providing an early warning of abnormal conditions of the propeller blade.

[0004] However, wind turbines are installed outdoors, and natural objects such as clouds, fog, or rain may appear within the detection range of the LiDAR from time to time, causing false alarms and affecting the accuracy of blade detection. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a blade detection method, device, equipment, and storage medium based on laser radar, which can eliminate the influence of natural objects on blade detection and improve the accuracy of blade detection.

[0006] In a first aspect, an embodiment of the present invention provides a laser radar-based blade detection method, which is applied to wind power equipment, wherein the wind power equipment includes a cabin, a blade, and a tower, and a laser radar for obliquely downward ranging is installed on the outer side of the cabin, and the detection range of the laser radar is located between the blade and the tower. The laser radar-based blade detection method includes:

[0007] Control the laser radar to measure a real-time ranging value, and when it is detected that the real-time ranging value is less than a preset reference distance value, construct a first sequence, and save a plurality of first candidate values ​​detected continuously into the first sequence, wherein the reference distance value is a measurement value of the laser radar based on a ground reference point, and the first candidate value is the real-time ranging value less than the reference distance value;

[0008] When the detected real-time distance measurement value is equal to the reference distance value, determining a first detection duration of the first sequence, wherein the first detection duration is a time interval between a collection time of a first first candidate value and a collection time of a last first candidate value in the first sequence;

[0009] When the first detection duration is within a preset duration interval and the difference values ​​between the first candidate values ​​are all less than or equal to a preset difference threshold, the first detected object corresponding to the first sequence is determined to be the blade.

[0010] According to some embodiments of the present invention, after determining that the first measured object corresponding to the first sequence is the blade, the method further includes:

[0011] determining a blade ranging value based on each of the first candidate values ​​of the first sequence;

[0012] Obtaining a preset tower height value and a ground calibration length value, wherein the ground calibration length value is a horizontal distance from the ground reference point to the tower;

[0013] Determine the ranging angle value based on the tower height value and the ground calibration length value;

[0014] A blade clearance value is determined based on the blade ranging value and the ranging angle value, wherein the blade clearance value is used to indicate a horizontal distance between a blade tip of the blade and the tower.

[0015] According to some embodiments of the present invention, determining the blade clearance value based on the blade ranging value and the ranging angle value includes:

[0016] Obtaining a preset blade length value and a radar calibration length value, wherein the radar calibration length value is a horizontal distance between the laser radar and the root of the blade;

[0017] Acquire a preset first distance interval, a second distance interval, and a third distance interval, wherein the first distance interval is a value range of the blade ranging value when the detection point of the laser radar is located at the tip of the blade, the second distance interval is a value range of the blade ranging value when the detection point of the laser radar is located at the tip of the blade, and the upper limit value of the third distance interval is less than the lower limit value of the second distance interval;

[0018] When the blade distance measurement value is in the first distance interval, the blade clearance value is calculated as follows: L8=L1×cosA1, wherein L8 is the blade clearance value, L1 is the blade distance measurement value, A1 is the distance measurement angle value, and A1=L6 / L7 is satisfied, L6 is the tower height value, and L7 is the ground calibration length value;

[0019] When the blade distance value is in the second distance interval, the blade clearance value is calculated as follows: Wherein, L2 is the radar calibration length value, and L0 is the blade length value;

[0020] When the blade distance value is in the third distance interval, the calculation formula of the blade clearance value is:

[0021] According to some embodiments of the present invention, before determining the blade clearance value based on the blade ranging value and the ranging angle value, the method further includes:

[0022] Obtaining a preset compensation coefficient, wherein the compensation coefficient is greater than 1;

[0023] The radar calibration length value is updated based on the compensation coefficient.

[0024] According to some embodiments of the present invention, after determining the first detection duration of the first sequence, the method further includes:

[0025] When the first detection duration is outside the preset duration interval, determining the first detected object as a target natural object, wherein the target natural object is rain or fog;

[0026] Alternatively, when the difference between at least one pair of the first candidate values ​​is greater than the preset difference threshold, the first detected object corresponding to the first sequence is determined as the target natural object;

[0027] Alternatively, when any of the first candidate values ​​is greater than the first distance interval, the first measured object corresponding to the first sequence is determined as the target natural object;

[0028] Alternatively, after the first measured object is determined to be the blade, when the real-time ranging value is re-detected to be less than the reference distance value, the re-detected real-time ranging value is determined to be a second candidate value, and when the time interval between the second candidate value and the first first candidate value of the first sequence is less than a preset interval threshold, the second measured object corresponding to the second candidate value is determined to be the target natural object.

[0029] According to some embodiments of the present invention, after controlling the laser radar to measure the real-time ranging value, the method further includes:

[0030] Determine the plurality of implemented distance measurement values ​​as spot check distance values ​​based on a preset spot check cycle, determine at least one of the spot check distance values ​​equal to the reference distance value as a ground distance measurement value, and determine the target proportion of the ground distance measurement value in the spot check data set;

[0031] When the target ratio is greater than or equal to a preset ratio threshold, it is determined that the laser radar is in a normal operating state;

[0032] When the target ratio is less than the ratio threshold and the ground distance measurement value or the first candidate value cannot be determined from the spot-checked distance value, it is determined that the laser radar is in an abnormal operating state.

[0033] According to some embodiments of the present invention, the wind power equipment further includes a wind measuring device, and the wind measuring device is used to detect wind force. After controlling the laser radar to measure the real-time ranging value, the method further includes:

[0034] Determine a current first wind force level, and when the first wind force level is greater than or equal to a preset level threshold, construct the first sequence;

[0035] When it is determined based on the first sequence that the first measured object is the blade, it is determined that the laser radar is in a normal operating state;

[0036] When it is not determined that the first measured object is the blade based on the first sequence, it is determined that the laser radar is in an abnormal operating state.

[0037] In a second aspect, an embodiment of the present invention provides a laser radar-based blade detection device, comprising at least one control processor and a memory for communicating with the at least one control processor; the memory stores instructions executable by the at least one control processor, and the instructions are executed by the at least one control processor so that the at least one control processor can execute the laser radar-based blade detection method as described in the first aspect above.

[0038] In a third aspect, an embodiment of the present invention provides an electronic device, comprising a laser radar-based blade detection device as described in the second aspect above.

[0039] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium storing computer-executable instructions, wherein the computer-executable instructions are used to execute the laser radar-based blade detection method as described in the first aspect above.

[0040] According to the laser radar-based blade detection method of the embodiment of the present invention, there are at least the following beneficial effects: controlling the laser radar to measure a real-time ranging value, and when it is detected that the real-time ranging value is less than a preset reference distance value, constructing a first sequence, and saving a plurality of first candidate values ​​detected continuously to the first sequence, wherein the reference distance value is a measurement value of the laser radar based on a ground reference point, and the first candidate value is the real-time ranging value less than the reference distance value; when the detected real-time ranging value is equal to the reference distance value, determining a first detection duration of the first sequence, wherein the first detection duration is the time interval between the acquisition moment of the first first candidate value and the acquisition moment of the last first candidate value in the first sequence; when the first detection duration is within a preset duration interval, and the difference values ​​between the respective first candidate values ​​are less than or equal to a preset difference threshold, determining the first object to be measured corresponding to the first sequence as the blade. According to the technical solution of an embodiment of the present invention, since the blades will pass through the detection range of the laser radar in a relatively short time during the rotation process, and natural objects such as clouds and fog will exist in the detection range of the laser radar for a relatively long time, the first detection duration can be compared with a preset duration interval to achieve a preliminary distinction between the blades and natural objects, and then the fact that the blade surface is usually a flat surface and the difference value of the first candidate value is small can be used to accurately distinguish between the blades and natural objects, thereby improving the accuracy of blade detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic diagram of a wind power device provided by an embodiment of the present invention;

[0042] Figure 2 is a flow chart of a blade detection method based on laser radar provided by another embodiment of the present invention;

[0043] Figure 3 is a schematic diagram of a laser radar not detecting a blade provided by another embodiment of the present invention;

[0044] Figure 4 is a schematic diagram of a laser radar detecting a blade tip provided by another embodiment of the present invention;

[0045] Figure 5 is a schematic diagram showing the area between the tip and the center of a blade detected by a laser radar provided by another embodiment of the present invention;

[0046] Figure 6 is a schematic diagram of a laser radar detecting the area between the center and the root of a blade provided by another embodiment of the present invention;

[0047] Figure 7 is a schematic diagram of correcting a radar calibration length value provided by another embodiment of the present invention;

[0048] Figure 8 It is a structural diagram of a laser radar-based blade detection device provided in another embodiment of the present invention. DETAILED DESCRIPTION

[0049] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0050] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0051] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0052] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0053] An embodiment of the present invention provides a laser radar-based blade detection method, device, equipment, and storage medium, wherein the laser radar-based blade detection method includes: controlling the laser radar to measure a real-time ranging value, and when it is detected that the real-time ranging value is less than a preset reference distance value, constructing a first sequence, and saving multiple first candidate values ​​detected continuously to the first sequence, wherein the reference distance value is a measurement value of the laser radar based on a ground reference point, and the first candidate value is the real-time ranging value less than the reference distance value; when the detected real-time ranging value is equal to the reference distance value, determining a first detection duration of the first sequence, wherein the first detection duration is the time interval between the acquisition time of the first first candidate value and the acquisition time of the last first candidate value in the first sequence; when the first detection duration is within a preset duration interval, and the difference values ​​between the first candidate values ​​are less than or equal to a preset difference threshold, determining the first object to be measured corresponding to the first sequence as the blade. According to the technical solution of an embodiment of the present invention, since the blades will pass through the detection range of the laser radar in a relatively short time during the rotation process, and natural objects such as clouds and fog will exist in the detection range of the laser radar for a relatively long time, the first detection duration can be compared with a preset duration interval to achieve a preliminary distinction between the blades and natural objects, and then the fact that the blade surface is usually a flat surface and the difference value of the first candidate value is small can be used to accurately distinguish between the blades and natural objects, thereby improving the accuracy of blade detection.

[0054] First, refer to Figure 1 , Figure 1 A schematic diagram of a wind power device provided by an embodiment of the present invention.

[0055] like Figure 1 and Figure 2 As shown, the wind power equipment of this embodiment includes a cabin 11, blades 20, and a tower 10. A laser radar 12 for obliquely downward ranging is installed on the outer side of the cabin 11. The detection range of the laser radar 12 is located between the blades 20 and the tower 10. The wind power equipment also includes a wind measuring device for detecting wind force.

[0056] It should be noted that the arrangement of the cabin 11, the blades 20 and the tower 10 is a technology well known to those skilled in the art and will not be elaborated herein.

[0057] It should be noted that a laser radar 12 is provided in the cabin 11. Figure 1 As shown, the laser radar 12 measures obliquely downward, and when the blade 20 is not offset, as shown in FIG. Figure 1 As shown by the solid line blade 20 in FIG. 1 , the blade 20 does not enter the measurement range of the laser radar 12. When the blade 20 moves toward the tower 10 under the action of wind, as shown in FIG. Figure 1As shown by the dotted blade 20 in the figure, the blade 20 will enter the detection range of the laser radar 12 to obtain the distance information of the blade 20. However, there is often fog or rain outdoors, and natural objects such as fog and rain will interfere with the detection of the laser radar 12. Figure 1 As shown, when the cloud 30 appears between the laser radar 12 and the blade 20, the laser radar 12 will measure the distance value between itself and the cloud 30. If it is identified as the distance of the blade 20, a false alarm is likely to occur. Therefore, the technical solution of this embodiment can distinguish between the blade 20 and natural objects, thereby improving the accuracy of the detection of the blade 20.

[0058] The following is based on Figure 1 The wind power equipment shown is used to further illustrate the technical solution of the embodiment of the present invention.

[0059] Reference Figure 2 , Figure 2 A flowchart of a blade detection method based on laser radar is provided in an embodiment of the present invention. The blade detection method based on laser radar includes but is not limited to the following steps:

[0060] S10, controlling the laser radar to measure the real-time ranging value, and when it is detected that the real-time ranging value is less than a preset reference distance value, constructing a first sequence, and saving a plurality of first candidate values ​​detected continuously into the first sequence, wherein the reference distance value is a measurement value of the laser radar based on a ground reference point, and the first candidate value is a real-time ranging value less than the reference distance value;

[0061] S20, when the detected real-time distance value is equal to the reference distance value, determining a first detection duration of the first sequence, wherein the first detection duration is a time interval between a collection time of the first first candidate value and a collection time of the last first candidate value in the first sequence;

[0062] S30: When the first detection duration is within a preset duration interval and the difference values ​​between the first candidate values ​​are all less than or equal to a preset difference threshold, the first detected object corresponding to the first sequence is determined to be a blade.

[0063] It should be noted that the laser radar performs real-time ranging after startup. When the blades do not enter the measurement range, the laser radar detects the reflected signal from the ground, so the real-time ranging value is equal to the reference distance value. When the blades enter the measurement range, since there are multiple blades, they will periodically appear in the detection range of the laser radar during the rotation process. The laser radar of this embodiment can perform ranging according to the set period. When the actual ranging value detected is less than the reference distance value, it can be determined that the blades or natural objects have entered the detection range of the laser radar, and the construction of the first sequence is started for subsequent judgment. Therefore, after citing the technical solution of this embodiment, the first sequence will be periodically constructed, and the same subsequent judgment can be performed after each first sequence is constructed.

[0064] It should be noted that when it is detected that the real-time ranging value is less than the reference distance value, the current real-time ranging value is recorded as the first first candidate value in the first sequence, and multiple real-time ranging values ​​are collected continuously. When they all meet the requirement of being less than the reference distance value, they are recorded in the first sequence according to the collection order, and writing data to the first sequence is stopped until the detected real-time ranging value is equal to the reference distance value. For example, after the blade appears in the detection range of the laser radar, the values ​​of the first candidate values ​​are relatively close within a period of time. When a sudden value jump occurs, it may be that the blade has left the detection range, and it is determined that the first sequence is completed.

[0065] It should be noted that the rotation of the blades is regular and the speed is usually predictable. Therefore, the time that the laser radar can continuously detect the blades also meets a certain range. In this embodiment, the interval between the acquisition moments of the first and last first candidate values ​​in the first sequence is used as the first detection duration. The first detection duration is used to characterize the time that the first object being measured is continuously detected, and the duration when the first object being measured is the blade is characterized by setting a preset duration interval. For example, the preset duration interval is [2.5ms, 30ms]. When the blades rotate faster, the laser radar can detect the blades within a continuous 2.5ms, and the first detection duration is 2.5ms. When the blades rotate slower, the laser radar can detect the blades within a continuous 30ms, and the first detection duration is 30ms. The value of the preset duration interval can be set according to the actual situation of the blades, and is not limited here. When the first detection duration is less than 2.5ms, it may be a temporary natural object, such as rain, so the first detection duration detected by the laser radar is short. If the first detection duration is greater than 30ms, a slow-moving natural object, such as fog, may appear. The movement speed of fog is slow, causing the laser radar to detect the first candidate value in a longer time. This embodiment can preliminarily distinguish natural objects from blades through the first detection duration by limiting the preset duration interval.

[0066] It should be noted that, according to the description of the above embodiment, the moving speed of natural objects is unpredictable, and there is also the possibility that the first detection duration meets the preset duration interval, so it is not possible to distinguish natural objects from blades only by the first detection duration. The surface of the blade is usually a flat surface. During the rotation process, the part detected by the laser radar is the horizontal line corresponding to a certain height point of the blade, that is, the various detection points of the first candidate value detected by the laser radar are theoretically consistent in height, but the shape of natural objects is usually irregular, so the numerical differences of the first candidate values ​​collected at different times may be large. This embodiment sets a preset difference threshold. When the difference value of multiple first candidate values ​​is less than or equal to the preset difference threshold, it can be determined that the difference value of multiple first candidate values ​​is usually not large, and the first measured object can be judged to be a blade, thereby achieving accurate distinction between natural objects and blades.

[0067] In addition, in one embodiment, after executing step S30, the following steps are also included but not limited to:

[0068] S41, determining a blade ranging value based on each first candidate value of the first sequence;

[0069] S42, obtaining a preset tower height value and a ground calibration length value, wherein the ground calibration length value is a horizontal distance from a ground reference point to the tower;

[0070] S43, determining a distance measurement angle value based on the tower height value and the ground calibration length value;

[0071] S44, determining a blade clearance value based on the blade ranging value and the ranging angle value, wherein the blade clearance value is used to indicate a horizontal distance between the tip of the blade and the tower.

[0072] It should be noted that after determining that the data in the first sequence is the blade distance value, it is necessary to determine the blade clearance value, that is, the horizontal distance between the blade tip and the tower, so as to detect whether the blade has a tower sweep risk. The maximum value of the first candidate values ​​can be used as the blade distance value, or the average value of the first candidate values ​​can be used as the blade distance value, which is not limited here.

[0073] It should be noted that if Figure 4 As shown in the figure, the ground reference point is the detection point on the ground where the laser emitted by the lidar is, so the ground calibration length value is a fixed value that can be measured in advance, and the tower height value is also a fixed value. The tower, the ground reference point and the lidar can construct a right triangle, so the ranging angle value can be calculated by simple trigonometric functions. After the blade ranging value is obtained, trigonometric functions can be performed based on the blade ranging value and the ranging angle value to determine the blade clearance value.

[0074] It should be noted that when the blade clearance value is less than the set alarm value, an alarm message can be sent to the maintenance personnel to remind them of the risk of blade sweeping the tower. Figure 3 As shown, the blade distance value may not be detected. In this case, the blade clearance value can use the default value, such as Figure 4 The value when the tip of the blade shown appears in the detection range of the laser radar is taken as the blade clearance value.

[0075] In addition, in one embodiment, step S44 specifically includes but is not limited to the following steps:

[0076] S441, obtaining a preset blade length value and a radar calibration length value, wherein the radar calibration length value is a horizontal distance between the laser radar and the root of the blade;

[0077] S442, obtaining a preset first distance interval, a second distance interval, and a third distance interval, wherein the first distance interval is a value range of the blade ranging value when the detection point of the laser radar is located at the tip of the blade, the second distance interval is a value range of the blade ranging value when the detection point of the laser radar is located at the tip of the blade, and the upper limit value of the third distance interval is less than the lower limit value of the second distance interval;

[0078] S443, when the blade distance measurement value is in the first distance interval, the blade clearance value is calculated as follows: L8=L1×cosA1, where L8 is the blade clearance value, L1 is the blade distance measurement value, A1 is the distance measurement angle value, and A1=L6 / L7 is satisfied, where L6 is the tower height value, and L7 is the ground calibration length value;

[0079] S444: When the blade distance measurement value is in the second distance interval, the blade clearance value is calculated as follows: Among them, L2 is the radar calibration length value, and L0 is the blade length value;

[0080] S445, when the blade distance measurement value is in the third distance interval, the blade clearance value is calculated as follows:

[0081] It should be noted that the blade length value is known in advance, such as Figure 3 As shown in the figure, the radar calibration length value is the horizontal distance between the laser radar and the root of the blade, which can also be measured after the blade is installed. Therefore, the blade length value and the radar calibration length value can be set in advance.

[0082] It should be noted that when the tip of the blade appears in the detection range of the laser radar, this implementation uses trigonometric functions to calculate the blade clearance value. Therefore, it is necessary to determine the position of the blade appearing in the detection line of the laser radar according to the numerical value of the blade detection value, thereby determining the type of the constructed right triangle. This embodiment distinguishes between the first distance interval, the second distance interval, and the third distance interval. When the blade ranging value is in the first distance interval, it can be determined that the detection point of the radar is located at the tip of the blade; when the blade ranging value is in the second distance interval, it can be determined that the detection point of the radar is located between the tip of the blade and the center of the blade; when the blade ranging value is in the third distance interval, it can be determined that the detection point of the radar is located between the center of the blade and the root of the blade; the shapes of the triangles constructed in different states are different, so the calculation method is different.

[0083] Exemplarily, the first distance interval, the second distance interval and the third distance interval can be estimated according to the blade length value. For example, when the blade length value is 95, the first distance interval can be [90, 95], the second distance interval can be (95, 95 / 2], and the third distance interval can be (0, 95 / 2).

[0084] It should be noted that if Figure 4 As shown in the figure, when the blade distance value is in the first distance interval, the blade distance value is large, and the detection point of the laser radar is located at the tip of the blade. It can be considered that the laser radar, the tip of the blade and the tower can form a Figure 4 For the right triangle shown in the figure, the blade clearance value can be obtained by calculating the base of the right triangle. First, the trigonometric function is used to calculate the ranging angle value A1=L6 / L7, where L6 is the tower height value and L7 is the ground calibration length value; then the principle of similar triangles is used to calculate L8=L1×cosA1, where L8 is the blade clearance value and L1 is the blade ranging value.

[0085] It should be noted that if Figure 5 As shown in , when the blade distance measurement value is in the second distance interval, the blade distance measurement value is smaller than the value when it is at the blade tip, and the detection point of the laser radar is located from the blade tip to the blade center, as shown in Figure 5 In the multiple right triangles formed by ABCD shown in the figure, L1×cosA1-L2 is the length of line segment AB, L1×sinA1 is the length of line segment EC, and line segment EC is equal to line segment AD, and line segment BD is the blade length value L0, so =∠ABD,∠ABD=∠FDC, so is the length of line segment CD, the blade clearance value

[0086]

[0087] It should be noted that if Figure 6As shown in Figure 2, when the blade range value is in the third distance interval, the detection point of the laser radar is located from the center of the blade to the root of the blade, and the triangle constructed between them is Figure 5 The embodiments shown are different, such as Figure 6 As shown, L2-L1×cosA1 is the length of limit BE, L1×sinA1 is the length of line segment EC, and line segment AC is the blade length value L0. Therefore, is ∠CBD, ∠CBD=∠ACF, so is the length of line segment AF, the blade clearance value

[0088] In addition, in one embodiment, before executing step S44, the following steps are also included but not limited to:

[0089] S431, obtaining a preset compensation coefficient, wherein the compensation coefficient is greater than 1;

[0090] S432, updating the radar calibration length value based on the compensation coefficient.

[0091] It should be noted that, according to the calculation formula of the above embodiment, it can be seen that the larger the value of L2, the smaller the calculated blade clearance value L8. Figure 7 As shown, the blade is usually deformed into an arc under the action of wind. If L0 measured when the blade is in a straight state is directly used for calculation, there is likely to be a certain error. This embodiment uses a compensation coefficient to compensate for L2, so that L2 is slightly larger than the actual value, ensuring that the calculated L8 is more accurate.

[0092] In addition, in one embodiment, after executing step S20, the following steps are also included but not limited to:

[0093] S51, when the first detection duration is outside the preset duration interval, determining the first detected object as a target natural object, wherein the target natural object is rain or fog;

[0094] S52, when the difference between at least one pair of first candidate values ​​is greater than a preset difference threshold, determining the first detected object corresponding to the first sequence as a target natural object;

[0095] S53, when any first candidate value is greater than the first distance interval, determining the first measured object corresponding to the first sequence as a target natural object;

[0096] S54, after the first measured object is determined to be a blade, when the real-time ranging value re-detected is less than the reference distance value, the re-detected real-time ranging value is determined as a second candidate value, and when the time interval between the second candidate value and the first first candidate value of the first sequence is less than a preset interval threshold, the second measured object corresponding to the second candidate value is determined to be a target natural object.

[0097] It should be noted that when the first detection duration is greater than the upper limit value of the preset duration interval, the moving duration of the first measured object is longer than the paddle blade, and it is likely to be slowly moving fog; when the first detection duration is less than the upper limit value of the preset duration interval, the moving duration of the first measured object is shorter than the paddle blade, and it is likely to be rapidly falling rain. Therefore, when the first detection duration is not within the preset duration interval, the first measured object can be determined as a target natural object, i.e., rain or fog.

[0098] It should be noted that since the surface of the blade is relatively flat, if the first measured object is a blade, the numerical difference between the first candidate values ​​is small. When the difference between at least one pair of first candidate values ​​is greater than the preset difference threshold, it can be determined that the surface of the first measured object is uneven, and the first measured object is determined to be a target natural object.

[0099] It should be noted that when any first candidate value in the first sequence is greater than the first distance interval, that is, the first measured object is located between the tip of the blade and the ground, it can be determined as a target natural object, such as fog located under the blade.

[0100] It should be noted that the operation of the blades is at a uniform speed. Although multiple first sequences will be continuously determined according to the rotation of the blades, the time intervals between the first sequences are fixed. For example, if the time interval from detecting one blade to detecting another blade is greater than 350ms, 350ms is used as the interval threshold. If the time interval between the second candidate value and the first first candidate value of the first sequence is less than the preset interval threshold, it can be determined that a target natural object has entered the detection range after completing a blade detection, and the second detected object is determined as the target natural object.

[0101] In addition, in one embodiment, after executing step S10, the following steps are also included but not limited to:

[0102] S11, determining a plurality of implemented distance measurement values ​​as the spot check distance values ​​based on a preset spot check cycle, determining at least one spot check distance value equal to the reference distance value as the ground distance measurement value, and determining a target proportion of the ground distance measurement value in the spot check data set;

[0103] S12, when the target ratio is greater than or equal to a preset ratio threshold, it is determined that the laser radar is in a normal operating state;

[0104] S13: When the target ratio is less than the ratio threshold and the ground distance measurement value or the first candidate value cannot be determined from the spot-checked distance value, it is determined that the laser radar is in an abnormal operating state.

[0105] It should be noted that during the actual operation, the laser radar may fail, so this embodiment detects the operating status of the laser radar by spot-checking the distance value. The spot-check cycle and the number of spot checks can be set according to actual needs. For example, 100 real-time distance measurement values ​​are spot-checked within 8 seconds as the spot-check distance value. Since the reference distance value is known, the ground distance value can be determined in the spot-check distance value, and the target ratio can be determined.

[0106] It should be noted that even if the propeller blades enter the detection range of the laser radar, the laser radar will detect the ground within a certain period of time. Therefore, the ground ranging value will meet a certain proportion in the spot check data set. When the target proportion is greater than the proportion threshold, it can be determined that the laser radar is in normal operation. Otherwise, the laser radar may be abnormal and cannot accurately measure the distance.

[0107] It should be noted that when the target ratio is less than the proportion threshold, it is very likely that natural objects have caused the number of ground ranging values ​​to be small, which does not necessarily mean that the laser radar has a fault. When the ground ranging value or the first candidate value is determined from the spot-checked distance value, it can also be determined that the laser radar is in a normal ranging state. If there is no relevant reflection signal, it can be determined that the laser radar has a fault and needs to be replaced in time.

[0108] In addition, in one embodiment, after executing step S10, the following steps are also included but not limited to:

[0109] S14, determining a current first wind force level, and constructing a first sequence when the first wind force level is greater than or equal to a preset level threshold;

[0110] S15, when it is determined based on the first sequence that the first measured object is a blade, it is determined that the laser radar is in a normal operating state;

[0111] S16: When it is not determined that the first measured object is a blade based on the first sequence, it is determined that the laser radar is in an abnormal operating state.

[0112] It should be noted that when the wind is strong, the probability of the propeller blades appearing in the detection range of the lidar is higher. For example, when there is a force 8 wind, there should be a signal that the propeller blades are monitored. At this time, if the first measured object is determined to be the propeller blade, it can be determined that the lidar is in normal operation.

[0113] It should be noted that if the detection signal of the blade is not detected under strong wind conditions, for example, in a wind speed of level 10, if it cannot be determined that the first detected object is the blade, it may be that the rain and fog have a significant impact and the lidar cannot measure the distance normally. Manual inspection or necessary protective measures are required, and in this scenario, ignore the lidar's alarm and determine the actual operating conditions through manual investigation.

[0114] like Figure 8 As shown, Figure 8 : is a structural diagram of a blade detection device based on laser radar provided by an embodiment of the present invention. The present invention also provides a blade detection device based on laser radar, comprising:

[0115] The processor 801 may be implemented by a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of the present application;

[0116] The memory 802 can be implemented in the form of a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 802 can store an operating system and other applications. When the technical solution provided in the embodiment of this specification is implemented by software or firmware, the relevant program code is stored in the memory 802, and the processor 801 calls and executes the laser radar-based blade detection method of the embodiment of this application;

[0117] Input / output interface 803, used to implement information input and output;

[0118] The communication interface 804 is used to realize the communication interaction between the device and other devices. The communication can be realized through a wired manner (such as USB, network cable, etc.) or a wireless manner (such as mobile network, WI FI, Bluetooth, etc.);

[0119] A bus 805 that transmits information between the various components of the device (e.g., the processor 801, the memory 802, the input / output interface 803, and the communication interface 804);

[0120] The processor 801 , the memory 802 , the input / output interface 803 and the communication interface 804 are connected to each other in communication within the device via a bus 805 .

[0121] An embodiment of the present application also provides an electronic device, comprising the laser radar-based blade detection device as described above.

[0122] An embodiment of the present application also provides a storage medium, which is a computer-readable storage medium. The storage medium stores a computer program, and when the computer program is executed by a processor, the above-mentioned laser radar-based blade detection method is implemented.

[0123] As a non-transient computer-readable storage medium, the memory can be used to store non-transient software programs and non-transient computer executable programs. In addition, the memory may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage devices. In some embodiments, the memory may optionally include a memory remotely arranged relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned networks include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof. The device embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and are implemented to be located in one place, or may also be distributed to multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment.

[0124] It will be appreciated by those skilled in the art that all or some of the steps and systems in the disclosed method above may be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or may be implemented as hardware, or may be implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or a non-transitory medium) and a communication medium (or a temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that may be used to store desired information and may be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically include computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0125] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the above-mentioned implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions under the shared conditions without violating the spirit of the present invention. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A blade detection method based on laser radar, characterized in that: Applied to wind power equipment, the wind power equipment includes a cabin, a blade, and a tower, a laser radar for oblique downward ranging is installed on the outside of the cabin, and the detection range of the laser radar is located between the blade and the tower. The blade detection method based on the laser radar includes: Control the laser radar to measure a real-time ranging value, and when it is detected that the real-time ranging value is less than a preset reference distance value, construct a first sequence, and save a plurality of first candidate values ​​detected continuously into the first sequence, wherein the reference distance value is a measurement value of the laser radar based on a ground reference point, and the first candidate value is the real-time ranging value less than the reference distance value; When the detected real-time distance measurement value is equal to the reference distance value, determining a first detection duration of the first sequence, wherein the first detection duration is a time interval between a collection time of a first first candidate value and a collection time of a last first candidate value in the first sequence; When the first detection duration is within a preset duration interval and the difference values ​​between the first candidate values ​​are all less than or equal to a preset difference threshold, the first detected object corresponding to the first sequence is determined to be the blade.

2. The blade detection method based on laser radar according to claim 1, characterized in that: After determining that the first measured object corresponding to the first sequence is the blade, the method further includes: determining a blade ranging value based on each of the first candidate values ​​of the first sequence; Obtaining a preset tower height value and a ground calibration length value, wherein the ground calibration length value is a horizontal distance from the ground reference point to the tower; Determine the ranging angle value based on the tower height value and the ground calibration length value; A blade clearance value is determined based on the blade ranging value and the ranging angle value, wherein the blade clearance value is used to indicate a horizontal distance between a blade tip of the blade and the tower.

3. The blade detection method based on laser radar according to claim 1, characterized in that: The determining of the blade clearance value based on the blade ranging value and the ranging angle value comprises: Obtaining a preset blade length value and a radar calibration length value, wherein the radar calibration length value is a horizontal distance between the laser radar and the root of the blade; Acquire a preset first distance interval, a second distance interval, and a third distance interval, wherein the first distance interval is a value range of the blade ranging value when the detection point of the laser radar is located at the tip of the blade, the second distance interval is a value range of the blade ranging value when the detection point of the laser radar is located at the tip of the blade, and the upper limit value of the third distance interval is less than the lower limit value of the second distance interval; When the blade distance measurement value is in the first distance interval, the blade clearance value is calculated as follows: L8=L1×cosA1, wherein L8 is the blade clearance value, L1 is the blade distance measurement value, A1 is the distance measurement angle value, and A1=L6 / L7 is satisfied, L6 is the tower height value, and L7 is the ground calibration length value; When the blade distance value is in the second distance interval, the blade clearance value is calculated as follows: Wherein, L2 is the radar calibration length value, and L0 is the blade length value; When the blade distance value is in the third distance interval, the calculation formula of the blade clearance value is:

4. The blade detection method based on laser radar according to claim 3 is characterized in that: Before determining the blade clearance value based on the blade ranging value and the ranging angle value, the method further includes: Obtaining a preset compensation coefficient, wherein the compensation coefficient is greater than 1; The radar calibration length value is updated based on the compensation coefficient.

5. The blade detection method based on laser radar according to claim 3 is characterized in that: After determining the first detection duration of the first sequence, the method further includes: When the first detection duration is outside the preset duration interval, determining the first detected object as a target natural object, wherein the target natural object is rain or fog; Alternatively, when the difference between at least one pair of the first candidate values ​​is greater than the preset difference threshold, the first detected object corresponding to the first sequence is determined as the target natural object; Alternatively, when any of the first candidate values ​​is greater than the first distance interval, the first measured object corresponding to the first sequence is determined as the target natural object; Alternatively, after the first measured object is determined to be the blade, when the real-time ranging value is re-detected to be less than the reference distance value, the re-detected real-time ranging value is determined to be a second candidate value, and when the time interval between the second candidate value and the first first candidate value of the first sequence is less than a preset interval threshold, the second measured object corresponding to the second candidate value is determined to be the target natural object.

6. The blade detection method based on laser radar according to claim 1, characterized in that: After controlling the laser radar to measure the real-time ranging value, the method further includes: Determine the plurality of implemented distance measurement values ​​as spot check distance values ​​based on a preset spot check cycle, determine at least one of the spot check distance values ​​equal to the reference distance value as a ground distance measurement value, and determine the target proportion of the ground distance measurement value in the spot check data set; When the target ratio is greater than or equal to a preset ratio threshold, it is determined that the laser radar is in a normal operating state; When the target ratio is less than the ratio threshold and the ground distance measurement value or the first candidate value cannot be determined from the spot-checked distance value, it is determined that the laser radar is in an abnormal operating state.

7. The blade detection method based on laser radar according to claim 6, characterized in that: The wind power equipment further includes a wind measuring device, which is used to detect wind force. After controlling the laser radar to measure the real-time distance measurement value, the method further includes: Determine a current first wind force level, and when the first wind force level is greater than or equal to a preset level threshold, construct the first sequence; When it is determined based on the first sequence that the first measured object is the blade, it is determined that the laser radar is in a normal operating state; When it is not determined that the first measured object is the blade based on the first sequence, it is determined that the laser radar is in an abnormal operating state.

8. A blade detection device based on laser radar, characterized in that: It includes at least one control processor and a memory for communicating with the at least one control processor; the memory stores instructions that can be executed by the at least one control processor, and the instructions are executed by the at least one control processor to enable the at least one control processor to execute the laser radar-based blade detection method as described in any one of claims 1 to 7.

9. An electronic device, characterized in that: Including the laser radar-based blade detection device as described in claim 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the laser radar-based blade detection method according to any one of claims 1 to 7.

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