Method for improving precision of laser clearance radar monitoring tip clearance value

Abstract

The application discloses a method for improving the precision of a laser clearance radar monitoring tip clearance value, and comprises the following steps: S1, acquiring laser clearance radar parameters and high-precision tilt angle sensor parameters; S2, determining an effective installation angle according to the high-precision tilt angle sensor parameters; S3, performing a moving average filtering based on the effective installation angle, and periodically updating corresponding parameters; S4, screening blade distance values; and S5, calculating the clearance value of the laser clearance radar. Compared with the prior art, the laser clearance radar beam angle output in real time and stably is used as a basic data source, and the tip clearance value is inversely calculated by combining the blade distance value output synchronously, so that the real-time high-precision output of the fan tip clearance value can be realized, and the influence of the installation angle deviation of the laser clearance radar caused by the cabin shaking on the precision of the clearance value is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of radar precision, and particularly relates to a method for improving precision of laser clearance radar monitoring of tip clearance value. BACKGROUND

[0002] With the increasing size of the impeller of the wind turbine, the increasing flexibility of the fan blade and the increasing height of the tower, the problem of tip clearance is becoming more and more prominent. The laser clearance radar is a kind of laser radar for monitoring the tip clearance distance in real time, which is generally installed at the lower or upper part of the nacelle and moves with the nacelle. During the operation of the fan, the nacelle will vibrate to different degrees due to the influence of complex wind conditions, which causes the installation angle of the laser clearance radar to change, and thus reduces the precision of the blade distance value obtained based on the laser clearance radar and the tip clearance value. When the nacelle is raised, the actual clearance value is greater than the clearance value monitored by the laser clearance radar, and when the nacelle is lowered, the actual clearance value is less than the clearance value monitored by the laser clearance radar, which to some extent increases the difficulty of the clearance warning control of the fan main control. SUMMARY

[0003] In order to solve the problem of deviation of the laser clearance radar clearance value caused by frequent vibration of the nacelle during the operation of the fan in the prior art, the purpose of the present application is to provide a method for improving the precision of the laser clearance radar monitoring of the tip clearance value

[0004] In order to achieve the above-mentioned object, the present application adopts the following technical scheme:

[0005] A method for improving the precision of the laser clearance radar monitoring of the tip clearance value, comprising:

[0006] S1, acquiring laser clearance radar parameters and high-precision tilt angle sensor parameters;

[0007] S2, determining an effective installation angle according to the high-precision tilt angle sensor parameters;

[0008] S3, performing moving average filtering based on the effective installation angle, and periodically updating the corresponding parameters;

[0009] S4, screening the blade distance value;

[0010] S5, calculating the clearance value of the laser clearance radar.

[0011] As a further preferred embodiment of the present application, the laser clearance radar parameters include the ranging value output by the laser clearance radar; and the high-precision tilt angle sensor parameters include the installation angle value output by the high-precision tilt angle sensor at the same output frequency as the ranging value.

[0012] The acquiring of the laser clearance radar parameters and the tilt angle sensor parameters comprises:

[0013] S1.1, the laser clearance radar is sequentially provided with a light beam 1, a light beam 2,..., and a light beam i from close to the tower tube to far away from the tower tube; the ranging values of the i light beams are respectively D1, D2,..., and Di;

[0014] S1.2, the angles between the light beam i and the vertical line are respectively θ i , and the difference values of the angles between the adjacent light beams are the same;

[0015] S1.3, the high-precision inclination sensor measures the angle between the light beam 1 and the vertical line, that is, the installation angle θ 1new of the light beam 1;

[0016] S1.4, based on the installation angle θ 1new of the light beam 1, combined with the fixed difference value, the installation angles θ 1new , θ 2new ,..., and θ 1new of the i light beams are output in real time, θ inew = θ i-1new + Δ

[0017] As a further preferred embodiment of the present application, the step of determining the effective installation angle according to the inclination sensor parameter comprises the following steps:

[0018] S2.1, the minimum value θ min and the maximum value θ max of the installation angle of the laser clearance radar are obtained;

[0019] S2.2, based on the installation angle θ inew of the light beam i, it is judged whether θ min ≤ θ inew < θ max ;

[0020] S2.3, when the above condition is met, the installation angle data is effective, and the effective position of the angle data is 1;

[0021] S2.4, when the above condition is not met, the installation angle data is invalid, and the effective position of the angle data is 0.

[0022] As a further preferred embodiment of the present application, the step of performing moving average filtering based on the effective installation angle and periodically updating the corresponding parameter comprises the following steps:

[0023] S3.1, when the number of effective installation angles Count is greater than 0 in the current update time period, the effective installation angles are sorted from small to large;

[0024] S3.2, 10% of the installation angle values are removed from the small end and the large end of the sorted installation angles;

[0025] S3.3, calculate the average value of the remaining installation angle values, and update the installation angle θ inew .

[0026] As a further preferred embodiment of the present application, the screening blade distance value comprises the following steps:

[0027] S4.1, obtain the minimum blade distance value Low_Distance and the maximum blade distance value High_Distance obtained by the laser clearance radar;

[0028] S4.2, compare the distance values of each light beam of the laser clearance radar with the minimum blade distance value Low_Distance and the maximum blade distance value High_Distance;

[0029] S4.3, when the minimum blade distance value Low_Distance≤distance value≤maximum blade distance value High_Distance, the distance value is recorded as a suspected blade distance value;

[0030] S4.4, based on the suspected blade distance value and the multi-beam correlation principle, the suspected blade distance value that meets any one of the multi-beam correlation conditions is recorded as a real blade distance value and is retained; the suspected blade distance value that does not meet is discarded.

[0031] As a further preferred embodiment of the present application, the multi-beam correlation condition comprises:

[0032] 1. The distance values of i light beams are all suspected blade distance values;

[0033] 2. The distance values of light beams 2,..., light beam i are all suspected blade distance values and light beam 1 is not a suspected blade distance value;

[0034] 3. The distance value of light beam i is a suspected blade distance value and the distance values of light beams 1, 2,..., i-1 are not suspected blade distance values.

[0035] As a further preferred embodiment of the present application, the calculation of the clearance value of the laser clearance radar comprises the following specific steps:

[0036] S5.1, according to the filtered installation angle and the blade distance value of the corresponding light beam, the clearance value of the light beam is calculated by the following formula:

[0037] C i = D i *sin(θ inew )+X_lidar-R,

[0038] Wherein, C iD is the distance from the blade tip to the tower wall, i.e. the clearance value, obtained by the laser clearance radar i beams i D is the blade ranging value of i beams obtained by the laser clearance radar inew X_lidar represents the coordinate obtained along the main axis of the nacelle when the laser clearance radar is installed, and R represents the corresponding tower radius at the blade tip;

[0039] S5.2, the clearance values obtained by i beams are weighted and calculated to obtain the final clearance value CL=p1*C1+p2*C2+p3*C3+…+p i C i , p1+p2+p3++…+p i =1, wherein p i represents the weight factor of the clearance value obtained by the beam i, and the value range is 0-1.

[0040] As a further preferred embodiment of the present application, the weight factor p1 of the beam clearance value closest to the tower side is 0.7-0.85, and the sum of the weight factors of the remaining beam clearance values is 1-p1.

[0041] The present application has the advantages of:

[0042] 1. The inclination sensor is integrated on the upper cover plate of the existing laser clearance radar, the output frequency of the control data is controlled, the frequency of the laser clearance radar output ranging value is the same as the frequency of the laser clearance radar installation angle value output by the inclination sensor, which not only helps the field personnel to quickly adjust the installation angle, but also realizes the real-time output of the installation angle value during the operation of the fan;

[0043] 2. The present application starts from the change data of the laser clearance radar installation angle value, and realizes the output of the second laser clearance radar single beam or multi-beam angle according to the moving average filtering method based on the blade running period length in the full-load state of the fan, and realizes the stable adaptive output of the laser clearance radar installation angle;

[0044] 3. The present application takes the real-time and stable output laser clearance radar beam angle as the basic data source, and inversely calculates the blade tip clearance value based on the synchronous output blade ranging value, which can realize the real-time high-precision output of the fan blade tip clearance value, and avoid the influence of the laser clearance radar installation angle deviation caused by the nacelle shaking on the clearance value precision. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 is the flowchart of the present application;

[0046] Figure 2 is a three-beam laser clearance radar installation schematic diagram;

[0047] Figure 3 This is a schematic diagram of the installation of a high-precision tilt sensor;

[0048] Figure 4 This is a diagram showing the pitch changes of the wind turbine nacelle;

[0049] Figure 5 This is a diagram showing the changes in the beam installation angle before and after filtering. Detailed Implementation

[0050] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0051] Combination Figure 1 A method for improving the accuracy of blade tip clearance value monitoring by laser clearance radar, comprising:

[0052] S1. Obtain the parameters of the laser air defense radar and the high-precision tilt sensor.

[0053] The parameters of the laser air-clearing radar include the ranging value output by the laser air-clearing radar.

[0054] S1.1 The laser air-clearing radar has beams 1, 2, ..., i arranged sequentially from the closest to the tower to the furthest away from the tower; the ranging values ​​of beam i are measured as D1, D2, ..., Di, and its output frequency is 50Hz.

[0055] S1.2, the angles between beam i and the perpendicular are θ and θ respectively. i Furthermore, the difference in the angle between adjacent beams is the same.

[0056] like Figure 2 As shown, the three-beam laser air clearance radar is installed at the bottom of the wind turbine nacelle, with the opening facing the ground. The three beams are arranged in sequence, with beam 1 being the one closest to the tower, beam 2 being the one in the middle, and beam 3 being the one furthest from the tower. The angles between the three beams and the vertical line are θ1, θ2, and θ3, respectively. The difference between the angles between beams 1 and 2 is the same as the difference between the angles between beams 2 and 3, where θ2 = θ1 + 2° and θ3 = θ2 + 2°.

[0057] The parameters of the high-precision tilt sensor include the installation angle value output by the high-precision tilt sensor at the same output frequency as the ranging value.

[0058] S1.3. A high-precision tilt sensor measures the angle between beam 1 and the vertical line, which is the installation angle θ of beam 1. 1new ;

[0059] S1.4, Installation angle θ based on beam 1 1new Combining a fixed difference, the installation angle θ of i beams is output in real time. 1new θ 2new =θ1new + Δ,..., θ inew = θ i-1new + Δ.

[0060] As Figure 3 shown, the precision inclination sensor is integrated in the laser clearance radar system, and the angle θ 1new between the light beam closest to the tower tube side and the vertical line directly measured by the high-precision inclination sensor is the basis, and the angle difference between each light beam is fixed and equal to Δ, which can output the installation angle θ 1new , θ 2new = θ 1new + Δ, θ 3new = θ 2new + Δ in real time, which meets the requirement of synchronization with the time stamp of the output three light beam ranging values D1, D2, D3, and the data output frequency of the installation angle is also 50Hz. The high-precision inclination sensor can output the change of the installation angle of the clearance radar in real time.

[0061] When the fan is running normally, the fan cabin will change the pitch angle, and the installation angle of the laser clearance radar will also change. When the fan cabin is raised by α, the installation angle of the three light beams of the laser clearance radar will change, among which the actual installation angle θ 1new of light beam 1 is θ1+ α, the actual installation angle θ 2new of light beam 2 is θ2+ α+ 2°, and the actual installation angle θ 3new of light beam 3 is θ3+ α+ 4°. When the fan cabin is lowered by α, the installation angle of the three light beams of the laser clearance radar will change, among which the actual installation angle θ 1new of light beam 1 is θ1– α, the actual installation angle θ 2new of light beam 2 is θ1– α+ 2°, and the actual installation angle θ 3new of light beam 3 is θ1– α+ 4°, as shown below. Figure 4

[0062] S2, according to the parameters of the high-precision inclination sensor, determine the effective installation angle.

[0063] S2.1, obtain the minimum value θ min and the maximum value θ max of the installation angle of the laser clearance radar.

[0064] S2.2, based on the installation angle θ inew of the light beam i, judge θ min ≤ θ inew < θ max .

[0065] S2.3, when the above conditions are met, the installation angle data is valid, and the angle data valid position is 1.​

[0066] S2.4 If the above conditions are not met, the installation angle data is invalid and the valid position of the angle data is 0.

[0067] The installation angle θ of the laser air clearance radar output beam 1 closest to the tower side 1new Based on this, firstly, according to the minimum installation angle θ theoretically obtained by the laser air clearance radar... min and maximum value θ max To determine the validity of the angle, if θ 1new Satisfying greater than or equal to θ min And less than θ max When the angle data is valid, the valid position is 1; otherwise, the valid position is 0. The minimum value θ is typically specified. min =0°, θ max =20°

[0068] S3. Perform moving average filtering based on the effective installation angle and periodically update the corresponding parameters;

[0069] S3.1. During the current update period, when the number of valid installation angles (Count) is greater than 0, the valid installation angles are sorted from smallest to largest.

[0070] S3.2 Remove 10% of the installation angle value from both the small and large ends of the sorted installation angles;

[0071] S3.3 Calculate the average of the remaining installation angle values ​​and update the installation angle θ. inew .

[0072] Based on the effective installation angle value θ of the laser air defense radar inew A moving average filter is applied, and the installation angle value is updated in 1-second intervals. The data update principle is that if the number of valid installation angles (Count) is greater than 0 within the current 1-second period, the Count installation angle values ​​are sorted from smallest to largest. After sorting, the smallest 10% and the largest 10% of valid installation angles are removed. The average value of the remaining 80% of installation angles is then calculated to update the installation angle value θ. 1new Otherwise, do not update the installation angle value θ. 1new .

[0073] Figure 5The change of the installation angle value before and after the moving average filtering is shown, the horizontal axis of the figure represents time, the unit is second (s), the vertical axis represents the beam installation angle, the unit is degree (°), the black points represent the installation angle change over time before filtering, and the black line represents the installation angle change over time after filtering. It can be seen from the figure that the installation angle update value obtained after the moving average filtering can reflect the change of the installation angle of the laser clearance radar during the operation of the fan, and the data update frequency meets the blade period requirement when the fan is fully running.

[0074] S4, screen the blade distance value;

[0075] S4.1, obtain the minimum blade distance value Low_Distance and the maximum blade distance value High_Distance obtained by the laser clearance radar;

[0076] The minimum blade distance value Low_Distance obtained by the laser clearance radar is set to 2000 cm, and the maximum blade distance value High_Distance is the length of the fan blade.

[0077] S4.2, compare the distance value of each beam of the laser clearance radar with the minimum blade distance value Low_Distance and the maximum blade distance value High_Distance;

[0078] S4.3, when the minimum blade distance value Low_Distance≤distance value≤maximum blade distance value High_Distance, the distance value is recorded as a suspected blade distance value;

[0079] S4.4, based on the suspected blade distance value and the multi-beam correlation principle, the suspected blade distance value that meets any one of the multi-beam correlation conditions is recorded as the true blade distance value, and is retained; the suspected blade distance value that does not meet is discarded.

[0080] The multi-beam correlation condition includes:

[0081] 1. The distance values of i beams are all suspected blade distance values;

[0082] 2. The distance values of beams 2,..., beam i are all suspected blade distance values and beam 1 is not a suspected blade distance value;

[0083] 3. The distance value of beam i is a suspected blade distance value and the distance values of beams 1, 2,..., i-1 are not suspected blade distance values.

[0084] S5, calculate the clearance value of the laser clearance radar.

[0085] S5.1. Based on the filtered installation angle and the corresponding blade distance value of the beam, calculate the beam clearance value using the following formula.

[0086] C i =D i *sin(θ inew )+X_lidar-R,

[0087] Among them, C i Let D be the distance from the blade tip to the tower wall obtained by the i beams of the laser clearance radar, which is the clearance value. i θ represents the blade ranging values ​​of the i beams acquired by the lidar radar. inew X_lidar represents the installation angle of the i beams output in real time by the laser air-clearing radar, X_lidar represents the coordinates obtained along the main axis of the nacelle when the laser air-clearing radar is installed, and R represents the tower radius corresponding to the blade tip.

[0088] S5.2. The final clearance value CL is obtained by weighting the clearance values ​​obtained from the i beams: CL = p1*C1 + p2*C2 + p3*C3 + ... + p i *C i ,p1+p2+p3++…+p i =1, where p i The weighting factor represents the net clearance value obtained by beam i, and its value ranges from 0 to 1.

[0089] The weighting factor p1 of the beam clearance value closest to the tower side is 0.7-0.85, and the sum of the weighting factors of the remaining beam clearance values ​​is 1-p1. When the beam does not trigger the blade, the weighting factor of its beam clearance value is 0; when a single beam triggers the blade, the weighting factor of its beam clearance value is 1.0.

[0090] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A method for improving the precision of laser clearance radar monitoring of tip clearance values, characterized in that The method comprises the following steps: S1, acquiring laser clearance radar parameters and high-precision tilt sensor parameters; S2, determining effective installation angles according to the high-precision tilt sensor parameters; S3, performing moving average filtering based on the effective installation angles, and periodically updating corresponding parameters; Specifically, the method comprises the following steps: S3.1, when the number of effective installation angles Count is greater than 0 in the current update time period, the effective installation angles are sorted from small to large; S3.2, 10% of the installation angle values are removed from the small end and the large end of the sorted installation angles; S3.3, calculate the average of the remaining installation angle values and update the installation angle θ inew ; S4, screening blade distance values; Specifically, the method comprises the following steps: S4.1, acquiring the minimum blade distance value Low_Distance and the maximum blade distance value High_Distance obtained by the laser clearance radar; S4.2, comparing the distance values of each light beam of the laser clearance radar with the minimum blade distance value Low_Distance and the maximum blade distance value High_Distance; S4.3, when the minimum blade distance value Low_Distance is less than or equal to the distance value and the distance value is less than or equal to the maximum blade distance value High_Distance, the distance value is recorded as a suspected blade distance value; S4.4, based on the suspected blade distance value and a multi-beam correlation principle, the suspected blade distance value that meets any one of the multi-beam correlation conditions is recorded as a real blade distance value and is retained; the suspected blade distance value that does not meet the condition is discarded; The multi-beam correlation conditions comprise: the distance values of i light beams are all suspected blade distance values; the distance values of light beams 2, …, and light beam i are all suspected blade distance values and light beam 1 is not a suspected blade distance value; the distance value of light beam i is a suspected blade distance value and the distance values of light beams 1, 2, …, and i-1 are not suspected blade distance values; S5, calculating the clearance value of the laser clearance radar.

2. The method for improving the precision of monitoring the tip clearance value of a laser tip clearance radar according to claim 1, characterized in that, The laser clearance radar parameters comprise distance values output by the laser clearance radar; the high-precision tilt sensor parameters comprise installation angle values output by the high-precision tilt sensor at the same output frequency as the distance values; The method of acquiring the laser clearance radar parameters and the tilt sensor parameters comprises the following steps: S1.1, the laser clearance radar is sequentially provided with light beam 1, light beam 2, …, and light beam i from the side close to the tower tube to the side far from the tower tube; the distance values of the i light beams are D1, D2, …, and Di respectively; S1.2, the angle between the light beam i and the vertical line is θ i , and the difference between the angles of adjacent light beams is the same. S1.3, the high-precision tilt sensor measures the angle between the light beam 1 and the vertical line, i.e. the installation angle θ of the light beam 1 1new ; S1.4, the installation angle θ of the light beam 1 is based 1new , in combination with the fixed difference value, the installation angle θ of the i light beams is output in real time 1new 2new = θ 1new + Δ,..., θ inew = θ i-1new + Δ.​ 3. The method for improving the precision of monitoring the tip clearance value of a laser tip clearance radar according to claim 2, characterized in that, The method of determining effective installation angles according to the tilt sensor parameters comprises the following steps: S2.1, obtaining the minimum value θ of the installation angle of the laser-clearing radar min and the maximum value θ max ; S2.2, based on the installation angle θ of the light beam i inew , determine θ min ≤ θ inew < θ max ; S2.3, when the above conditions are met, the installation angle data is effective, and the angle data effective position is 1; S2.4, when the above conditions are not met, the installation angle data is invalid, and the angle data effective position is 0.

4. The method for improving the precision of laser clearance radar monitoring tip clearance value according to claim 1, characterized in that, The method of calculating the clearance value of the laser clearance radar comprises the following specific steps: S5.1, the clearance value of each light beam is calculated according to the filtered installation angle and the blade distance value of the corresponding light beam by the following formula: C i =D i ×sin(θ inew )+X_lidar-R, wherein C i is the distance from the blade tip to the tower wall, i.e. the clearance value, D i is the blade ranging value of the i-th beam obtained by the laser clearance radar, θ inew is the installation angle of the i-th beam output by the laser clearance radar in real time, X_lidar represents the coordinate obtained along the main axis direction of the nacelle when the laser clearance radar is installed, and R represents the corresponding tower radius at the blade tip. S5.

2. The final clearance value CL is obtained by weighting the clearance values ​​obtained from the i beams: CL = p1 × C1 + p2 × C2 + p3 × C3 + ... + p i × C i ,p1+ p2+ p3+…+p i =1, where p i The weighting factor represents the net clearance value obtained by beam i, and its value ranges from 0 to 1.

5. The method for improving the precision of monitoring the tip clearance value of a laser tip clearance radar according to claim 4, characterized in that, the weight factor p1 of the clearance value of the light beam closest to the tower tube side is 0.75-0.85, and the sum of the weight factors of the clearance values of the remaining light beams is 1-p1.

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