Helicopter composite blade root thickness and extension digital detection method

Abstract

The invention belongs to the technical field of helicopter rotor system digital testing, and relates to a helicopter composite blade root thickness and extension digital detection method. The method comprises the following steps: determining a measurement area of a paddle root or a span; according to different measurement areas, a helicopter composite blade digital comprehensive detection system is adopted to measure the corresponding blade root thickness or blade extension length; the digital comprehensive detection system for the helicopter composite blade comprises a special positioning tool, a movable ground rail, a linear laser measuring instrument, a measuring system and a robot auxiliary device.

Description

Technical Field

[0001] The invention belongs to the technical field of digital testing of helicopter rotor systems, and relates to a digital detection method for the thickness and span of a helicopter composite blade root. Background Art

[0002] After the helicopter blades are molded, it is necessary to test the blade extension and the thickness of the limited area at the blade root. The measurement accuracy is relatively high. The current manual measurement using traditional materials and tools mainly has the following problems:

[0003] 1. The measurement workload is large, the repetitiveness is high, and the manual operation is adopted, which is intensive and inefficient, and cannot meet the batch production requirements of various models;

[0004] 2. Manual inspection has poor consistency and it is difficult to ensure product quality, which affects the parts qualification rate and assembly cycle;

[0005] 3. In terms of test data collection, manual records and paper media are still the main methods, which affects data management and transmission and has poor traceability; Summary of the invention

[0006] Purpose of the invention: To study the digital measurement method of blade length and thickness in a limited area at the root of the blade based on robot-based intelligent detection technology, so as to solve the problems existing in manual inspection of large components and large quantities of parts, accurately measure to improve measurement accuracy and efficiency, and reduce the problem of measurement deviation caused by human factors.

[0007] Technical solution:

[0008] A method for digitally detecting the thickness and extension of a helicopter composite blade root is provided, the method comprising:

[0009] Determine the measurement area for blade root or span;

[0010] According to different measurement areas, the helicopter composite blade digital comprehensive detection system is used to measure the corresponding blade root thickness or blade span;

[0011] The helicopter composite blade digital comprehensive inspection system includes: special positioning tooling, mobile ground rail, line laser measuring instrument, measurement system, and robot auxiliary device;

[0012] The special positioning tooling and the mobile ground rail are rigidly connected to form an integral platform; the robot auxiliary device is installed on the mobile ground to achieve long-distance precise movement; the line laser measuring instrument is used to scan the surface of the object blade, and cooperates with the measurement system to convert the measured data into a plane graphic and calculate the required related parameters; the line laser measuring instrument is installed on the robot auxiliary device, and in conjunction with the mobile ground rail, it can achieve long-distance or multi-directional scanning.

[0013] Furthermore, the measurement area of ​​the propeller root is a triangular area formed between the two bushing holes of the blade and close to the root; the triangular area is a hard plate, and the data flatness is relatively high.

[0014] Furthermore, the helicopter composite blade digital comprehensive detection system is used to measure the corresponding blade root thickness or blade span, including:

[0015] The blade to be measured is placed on a special positioning tool, the measuring system is started, and the mobile ground rail carries the measuring body line laser measuring instrument to move horizontally at a uniform speed to perform continuous measurement of the blade root part: during the measurement, point data from position a on the blade root plane to position b on the blade root plane and point data of the two bushing holes at the root of the blade are collected; among them, position a is the blade root position, and position b is the blade tip position.

[0016] Furthermore, continuous measurement of the propeller root is performed, including:

[0017] ① Obtain the point data of the blade contour: After the blade contour is arranged at equal intervals under the vertical laser beam, obtain the corresponding value in the coordinate system;

[0018] The role of the point data of the blade profile:

[0019] b. According to the collected contour point data, the corresponding points are placed in the spatial coordinate system determined in the detection system, and then these points are connected to form a central line, and the spatial base coordinates corresponding to the central line are found;

[0020] b. Use the formed connection line to compare the angle formed by the approaching line segment with the normal line of the measuring body line laser measuring instrument, which is the angle formed by the Z0 position of the blade and the measuring body line laser measuring instrument after the blade is placed on the special positioning fixture; the Z0 position is the 0° position of the blade with higher accuracy and without deflection;

[0021] c. Determine the propeller root data threshold: When the convex edge position of the bushing hole is not reached, the process of using the formed connection line will be continuously recorded, and the corresponding change amplitude value will be obtained from the record, and an acceptable range for fitting will be selected from them;

[0022] e. When the edge of the bushing hole is not reached, find an average value from the values ​​in the ab segment to calculate the position in the bushing hole;

[0023] Determine the bushing edge value: the middle value + a raised height dx, where dx is a fixed value in blade production;

[0024] ② Determine the value of the bushing edge collapse area: When a value of 0 or non-existent appears in the measurement data area, it indicates that irregular values ​​may appear in the measurement data. Compare it with the result of the bushing edge area + bushing outer radius to accurately determine the Z0 position and record the ground rail value X at that position;

[0025] ③ After the ground track reaches the X position, the data of the blade AB surface is collected, and the above transformation process and threshold are combined to filter out the component data in the triangle; the mean of the data in the A surface is formed into (x1, y1, z1) and the mean of the data in the B surface is formed into (x2, y2, z2), and finally the formula [(x1-x2) 2 +(y1-y2) 2 +(z1-z2) 2 ]1 / 2 calculate the thickness value;

[0026] ④ According to the above content and for the convenience of use in subsequent calculations, the following data need to be saved: the ground track position of Z0, the deflection angle of the blade after it is placed in the tooling, the basic data of linear transformation, the threshold value, and the blade root thickness value.

[0027] Furthermore, the measurement methods include fixed-point static measurement and dynamic measurement.

[0028] Furthermore, the helicopter composite blade digital comprehensive detection system is used to measure the corresponding blade root thickness or blade span, including:

[0029] The middle point of the blade is set as a fixed point, and when the track reaches the blade tip transition position Z3, it becomes a dynamic measurement process;

[0030] Static measurement: The ground rail stops at the position where the blade needs to be measured, and the measurement starts when the dynamic measurement is converted to a static stable state;

[0031] Dynamic measurement: The ground track carries the measuring body in a uniform horizontal continuous motion measurement method;

[0032] The dynamic measurement moves from Z3 to the blade tip Z4. The data of the detection system will have a process in which the data value range continues to decrease until the data disappears completely. When the data disappears, it means that the blade has reached the final end.

[0033] Based on the above data, calculate the blade span = Z0 ground track value - final end ground track value.

[0034] Furthermore, the position data of the ground rail changes in real time in response to changes in the measurement position.

[0035] Furthermore, the accuracy of the position measurement data is determined by the PWM duty cycle, the number of mechanical gear rotation teeth and the unit tooth linear distance.

[0036] Beneficial effects: This test method has simple requirements for the positioning, placement and fixing of the product (blade), and does not require high-precision clamping and positioning. It only needs to place the product on a special positioning tool. The entire measurement process uses one-button operation, which reduces the contact between people and products, improves operating efficiency, and avoids the inaccuracy of measurement caused by human factors. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is an axial view of a digital integrated inspection system for helicopter composite blades;

[0038] Figure 2 It is a top view of the blade;

[0039] Figure 3 It is a cross-section of the paddle heel;

[0040] Figure 4 It is a symbol of the bushing Figure 1 ;

[0041] Figure 5 It is a symbol of the bushing Figure 2 ;

[0042] Figure 6 This is a schematic diagram of the blade test coordinate position. DETAILED DESCRIPTION

[0043] like Figure 1 As shown, a digital comprehensive detection system for helicopter composite blades is provided, including: a special positioning tool 1, a mobile ground rail 2, a line laser measuring instrument 3, a measuring system 4, and a robot auxiliary device 5.

[0044] The special positioning tool 1 and the mobile ground rail 2 are rigidly connected to form an integral platform; the robot auxiliary device 5 is installed on the mobile ground rail 2 to achieve long-distance precise movement; the line laser measuring instrument 3 is used to scan the surface of the object blade, and cooperates with the measuring system 4 to convert the measured data into a plane figure and calculate the required related parameters; the line laser measuring instrument 3 is installed on the robot auxiliary device 5, and cooperates with the mobile ground rail 2 to achieve long-distance or multi-directional scanning.

[0045] The special positioning fixture 1 is composed of a first leveling foot 11, a fixture platform 12, a contour positioning block 13, etc. By adjusting the nut on the first leveling foot, the heights of the multiple contour positioning blocks on the fixture platform can be adjusted to be on the same level. This ensures that after the blade of the product to be tested is placed on the positioning block, the product is placed horizontally and remains in a free state to prevent the curved surface from bending after the product is placed. The contour positioning block is specially customized according to the shape of the product's outer surface, and the part of the product that contacts the product is made of "soft" material to avoid scratching the outer surface of the product.

[0046] The mobile track 2 is composed of a second leveling foot 21, a platform 22, a gear transmission mechanism 23, a servo system 24, etc. The entire platform is made of an integrated welded frame to prevent the accuracy of the entire mobile track from being reduced due to segmented splicing. At the same time, the gear and rack in the gear transmission mechanism adopt a helical meshing method, which can reduce the meshing gap between the gear and the rack, thereby providing the repeatability accuracy of the movement. The entire platform can adjust the level of the platform by adjusting the nuts on the leveling foot. And a rigid connection is adopted between the special positioning tool 1, and the leveling feet are used to ensure that the adjustment planes between the two are parallel at the same level.

[0047] Line laser measuring instrument 3 is a mature standard product on the market, which can scan and measure a certain length at the same time. For example, if the maximum length of a single section of a blade is 580mm, the selected line laser measurement length must be greater than 580mm, so that a section can be measured at one time and relevant data of the entire section can be collected. On the contrary, if the measurement length is less than 580mm, more than two acquisitions and splicing are required, which will increase the cumulative error.

[0048] The measurement system 4 is a set of customized measurement software, which is used in conjunction with the line laser measuring instrument 3. This system uses two sets of line lasers, each of which can simulate half of the shape. The measurement system collects the data of each light source in the line laser, thereby combining and simulating the measured shape figure. Then the algorithm is used to calculate the relevant parameters required in the figure.

[0049] The robot auxiliary device 5 is used to clamp the line laser measuring instrument 3, and is integrally installed on the movable ground rail 2. According to the needs, it can meet the requirements of measuring any position of the product to be measured.

[0050] The measuring steps of the present invention are as follows:

[0051] Step 1: Product installation and positioning: Use a crane or other method to place the product (blade) along the guide block onto the contoured positioning block on the tooling, thus completing the positioning and clamping of the product.

[0052] Step 2: On the computer operation interface, open the customized measurement software, click the "One-key measurement" button, and then wait for the system to complete the automatic measurement. During the automatic measurement process, the data values ​​and results to be measured can be displayed on the measurement software screen.

[0053] Step 3: After the equipment completes the automatic measurement, the measurement data can be automatically stored. The measured data (EXCEL table data) can be manually exported from the measurement software and observed and analyzed.

[0054] Step 4: Use a crane or other means to take out the product (blade) to complete this measurement task.

[0055] R&D measurement system for blade root thickness and span measurement:

[0056] ·Measuring method of propeller root thickness

[0057] 1. Determination of propeller root measurement area:

[0058] The measurement area is generally the part between the two bushing holes of the blade close to the root (such as Figure 6 The triangular area is a hard plate, and the data is relatively smooth.

[0059] 2. Paddle root thickness measurement method:

[0060] The blade to be measured is placed on a special positioning fixture 1, the measuring system is started, and the mobile ground rail 2 moves horizontally with the measuring body line laser measuring instrument 3 at a uniform speed to continuously measure the blade root part (from the blade root plane a position to the blade root plane b position). During the measurement, the point data of the blade ab contour ① and the point data of the two bushing holes at the blade root ② (the point data of the two bushing holes of the blade in the coordinate system) are collected:

[0061] ① The point data of the blade contour, i.e. the blade shape, is arranged at equal intervals under the vertical laser beam.

[0062] Then correspond to the corresponding values ​​in the coordinate system.

[0063] The main functions of the point data of the blade profile are:

[0064] a. According to the collected contour point data, put them into the spatial coordinate system determined in the measurement volume, connect these points to form a line, and find the spatial base coordinates corresponding to the line;

[0065] b. Use the formed connection line to compare the approaching line segment with the normal line of the measuring device to form an angle, which is the angle after the blade is placed on the special positioning fixture 1. Figure 2 The angle formed by the blade Z0 position (Z0 position is the non-deflected 0° position with higher accuracy in the blade) and the measuring body line laser measuring instrument 3;

[0066] c. Determination of the propeller root data threshold (before reaching the convex edge position of the bushing hole, the process in a will be continuously recorded, and the corresponding change amplitude value will be obtained from the record, from which an acceptable range can be selected);

[0067] d. Use the formed connection to display the graphics on the PC in real time;

[0068] e. Before reaching the edge of the bushing hole, find an average value from the values ​​in segment ab and use it to calculate the position inside the bushing hole.

[0069] Determination of bushing edge value: average value + height of a protrusion dx (fixed value in blade production)

[0070] Fixed value) (this data can be collected reliably)

[0071] ② Determination of the value of the bushing edge collapse area: When a value of 0 or non-existent appears in the measurement data area

[0072] Determination of Z0 baseline: f. When the maximum range of 0 or non-existent value appears in the data area

[0073] g, bushing edge area + r (outer radius of bushing) (determined value)

[0074] h. Compare and analyze the above f and g (irregular values ​​may appear in f and need to be compared with the data in g to accurately determine the Z0 position), and record the ground track value X at that position;

[0075] ③ After the ground track reaches the X position, the data of surface A and surface B are collected, and the above transformation process and threshold are combined to filter out the component data within the triangle; the mean of the data in surface A forms (x1, y1, z1) and the mean of the data in surface B forms (x2, y2, z2), and finally the formula [(x1-x2) 2 +(y1-y2) 2 +(z1-z2) 2 ]1 / 2Calculate the thickness value

[0076] ④ According to the above content and for the convenience of use in subsequent calculations, the following data need to be saved: the ground track position of Z0, the deflection angle of the blade after it is placed in the tooling, the basic data of linear transformation, the threshold value, and the blade root thickness value.

[0077] ·Extension length calculation method

[0078] 1. The measurement of the middle point is a fixed-point static measurement. When the track reaches the blade Z3, it becomes a dynamic measurement process;

[0079] Static measurement: The ground rail stops at the position where the blade needs to be measured, and the measurement starts when the dynamic measurement is converted to a static stable state;

[0080] Dynamic measurement: The ground track carries the measuring body in a uniform horizontal continuous motion measurement method;

[0081] Conversion between propeller blade position and actual ground rail position:

[0082] Assume that: after the blade is fixed on the special positioning fixture 1, the extension value increases from the front end to the rear end, and the movement value of the ground rail increases from the rear end to the front end (the directionality of the ground rail position is fixed)

[0083] like Figure 6As shown, the blade Z0 position → the position value of the ground rail [X (mm)]

[0084] The position description of the blade (Z****), where **** represents the distance from the Z0 position to the back straight line. Example: The transformation of the actual position of the blade Z3 and the ground rail:

[0085] Assume: blade Z0 position → ground rail position value (7338mm)

[0086] Then: the value of the ground rail position corresponding to the blade Z3 position is 7100, 7338-7100=238 (mm)

[0087] The position data of the ground rail changes in real time with the change of the measured position and is displayed on the PC window interface. At the same time, the accuracy of the position measurement data is determined by the PWM duty cycle, the number of mechanical gear rotation teeth and the unit tooth linear distance;

[0088] 2. Dynamic measurement moves from Z3 to Z4. The data of the measurement body will have a process in which the data value range continues to decrease until the data disappears completely (determined by the intuitive characteristics of the blade shape). When the data disappears, it means that the blade has reached the final end.

[0089] Z0 ground track value - final end ground track value = blade length.

Claims

1. A digital detection method for the thickness and span of a helicopter composite blade root, characterized in that: The method includes: Determine the measurement area for blade root or span; According to different measurement areas, the helicopter composite blade digital comprehensive detection system is used to measure the corresponding blade root thickness or blade span; The helicopter composite blade digital comprehensive inspection system includes: special positioning tooling, mobile ground rail, line laser measuring instrument, measurement system, and robot auxiliary device; The special positioning tooling and the mobile ground rail are rigidly connected to form an integral platform; the robot auxiliary device is installed on the mobile ground to achieve long-distance precise movement; the line laser measuring instrument is used to scan the surface of the object blade, and cooperates with the measurement system to convert the measured data into a plane graphic and calculate the required related parameters; the line laser measuring instrument is installed on the robot auxiliary device, and in conjunction with the mobile ground rail, it can achieve long-distance or multi-directional scanning.

2. The method according to claim 1, characterized in that The measurement area of ​​the propeller root is the triangular area formed between the two bushing holes of the blade and close to the root; the triangular area is a hard plate, and the data flatness is relatively high.

3. The method according to claim 2, characterized in that The helicopter composite blade digital comprehensive detection system is used to measure the corresponding blade root thickness or blade span, including: The blade to be measured is placed on a special positioning tool, the measuring system is started, and the mobile ground rail carries the measuring body line laser measuring instrument to move horizontally at a uniform speed to perform continuous measurement of the blade root part: during the measurement, point data from position a on the blade root plane to position b on the blade root plane and point data of the two bushing holes at the root of the blade are collected; among them, position a is the blade root position, and position b is the blade tip position.

4. The method according to claim 3, characterized in that Continuous measurement of the blade root, including: ① Obtain the point data of the blade contour: After the blade contour is arranged at equal intervals under the vertical laser beam, obtain the corresponding value in the coordinate system; The role of the point data of the blade profile: a. According to the collected contour point data, the corresponding points are placed in the spatial coordinate system determined in the detection system, and then these points are connected to form a central line, and the spatial base coordinates corresponding to the central line are found; b. Use the formed connection line to compare the angle formed by the approaching line segment with the normal line of the measuring body line laser measuring instrument, which is the angle formed by the Z0 position of the blade and the measuring body line laser measuring instrument after the blade is placed on the special positioning fixture; the Z0 position is the 0° position of the blade with higher accuracy and without deflection; c. Determine the propeller root data threshold: When the convex edge position of the bushing hole is not reached, the process of using the formed connection line will be continuously recorded, and the corresponding change amplitude value will be obtained from the record, and an acceptable range for fitting will be selected from them; e. When the edge of the bushing hole is not reached, find an average value from the values ​​in the ab segment to calculate the position in the bushing hole; Determine the bushing edge value: average value + a raised height dx, dx is a fixed value in blade production; ② Determine the value of the bushing edge collapse area: When a value of 0 or non-existent appears in the measurement data area, it indicates that irregular values ​​may appear in the measurement data. Compare it with the result of the bushing edge area + bushing outer radius to accurately determine the Z0 position and record the ground rail value X at that position; ③ After the ground track reaches the X position, the data of the blade AB surface is collected, and the above transformation process and threshold are combined to filter out the component data in the triangle; the mean of the data in the A surface is formed into (x1, y1, z1) and the mean of the data in the B surface is formed into (x2, y2, z2), and finally the formula [(x1-x2) 2 +(y1-y2) 2 +(z1-z2) 2 ]1 / 2 calculate the thickness value; ④ According to the above content and for the convenience of use in subsequent calculations, the following data need to be saved: the ground track position of Z0, the deflection angle of the blade after it is placed in the tooling, the basic data of linear transformation, the threshold value, and the blade root thickness value.

5. The method according to claim 1, characterized in that The measurement methods include fixed-point static measurement and dynamic measurement.

6. The method according to claim 5, characterized in that The helicopter composite blade digital comprehensive detection system is used to measure the corresponding blade root thickness or blade span, including: The middle point of the blade is set as a fixed point, and when the track reaches the blade tip transition position Z3, it becomes a dynamic measurement process; Static measurement: The ground rail stops at the position where the blade needs to be measured, and the measurement starts when the dynamic measurement is converted to a static stable state; Dynamic measurement: The ground track carries the measuring body in a uniform horizontal continuous motion measurement method; The dynamic measurement moves from Z3 to the blade tip Z4. The data of the detection system will have a process in which the data value range continues to decrease until the data disappears completely. When the data disappears, it means that the blade has reached the final end. Based on the above data, calculate the blade span = Z0 ground track value - final end ground track value.

7. The method according to claim 6, characterized in that The position data of the ground rail changes in real time as the measurement position changes.

8. The method according to claim 7, characterized in that The accuracy of the position measurement data is determined by the PWM duty cycle, the number of rotating teeth of the mechanical gear and the unit tooth linear distance.

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