Helicopter composite blade digital comprehensive detection system and method thereof

Abstract

The invention belongs to the technical field of helicopter rotor system testing, and relates to a helicopter composite blade digital comprehensive detection system and method. The detection system comprises a special positioning tool, a movable ground rail, a line laser measuring instrument, a measuring system and a robot auxiliary device. The two sets of special positioning tools are rigidly connected with the movable ground rail respectively to form an integral platform; the robot auxiliary device is installed on the movable ground rail, and long-distance accurate movement is achieved. The tail end of the robot auxiliary device clamps the linear laser measuring instrument, and long-distance or multi-directional scanning can be realized in cooperation with the movable ground rail; and the line laser measuring instrument is used for scanning the surface of the blade mounted on the special positioning tool, converting measured data into a plane figure in cooperation with the measuring system, and calculating required related parameters.

Description

Technical Field

[0001] The invention belongs to the technical field of helicopter rotor system testing, and relates to a helicopter composite blade digital comprehensive detection system and method. Background Art

[0002] The comprehensive inspection elements of blade shape include: blade span, blade root thickness, chord measurement, trailing edge thickness, maximum airfoil thickness, and blade twist angle. The measurement accuracy requirements are relatively high. Currently, manual measurement using traditional materials and tools has the following main 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 intelligent detection technology based on robots to solve the problems existing in manual detection of large components and large quantities of parts, achieve one-time clamping, accurate measurement, improve measurement accuracy and efficiency, and reduce the problem of measurement deviation caused by human factors. At the same time, a system can complete the measurement of multiple types of blades, achieve versatility, and realize the digitization of comprehensive blade measurement.

[0007] Technical Solution

[0008] In the first aspect, a digital integrated inspection system for helicopter composite blades and a robot-assisted device are provided;

[0009] Two sets of special positioning fixtures are rigidly connected to the mobile ground rails to form an integral platform. The robot-assisted device is installed on the mobile ground rails to achieve long-distance precise movement. The end of the robot-assisted device clamps the line laser measuring instrument, which can achieve long-distance or multi-directional scanning in conjunction with the mobile ground rails. The line laser measuring instrument is used to scan the surface of the blade installed on the special positioning fixture, and in conjunction with the measurement system, the measured data is converted into a plane graph and the required related parameters are calculated.

[0010] The special positioning tooling includes a first leveling foot, a tooling platform, and a contour positioning block; the tooling platform is installed on the ground by adjusting the leveling foot and the nut, and the heights of multiple contour positioning blocks on the tooling platform are adjusted to be on the same horizontal plane by adjusting the nut on the first leveling foot; multiple groups of mounting holes are provided on the tooling platform for installing contour positioning blocks; the contour positioning block is specially customized according to the shape of the outer surface of the leading edge of the blade, and the blade is placed upright along the length direction, and the part in contact with the leading edge of the blade is made of "soft" material to avoid scratching the outer surface of the blade;

[0011] The mobile ground rail includes a second leveling foot, a platform, a servo system, a gear transmission mechanism, a slide rail, a lubrication system, and a flexible drag chain;

[0012] A row of second leveling feet is arranged at the lower part of one side of the platform, a slide rail is installed on the platform, a servo system is installed on two inner side walls of the platform, a servo system is installed at one end of the slide rail, and the servo system drives the robot auxiliary device to slide on the slide rail through a gear transmission mechanism;

[0013] The platform is made of an integrated welded frame, and the gear and rack in the gear transmission mechanism adopt the helical meshing method; the platform is rigidly connected to the special positioning tooling, and the second leveling foot is used to ensure that the adjustment plane between the two is parallel at the same level;

[0014] The measuring length of the laser of the line laser measuring instrument must be greater than the maximum length of a single section of the blade.

[0015] In a second aspect, a digital comprehensive detection method for helicopter composite blades is provided, using the digital comprehensive detection system for helicopter composite blades described in the first aspect, the method comprising:

[0016] When a pair of laser detection lines of the line laser measuring instrument reach the measurement positions specified by the upper and lower surface measurement tasks of the blade, respectively, the callback function of the measurement system is called to measure the upper surface original contour data LineA and the lower surface original contour data Line B, each containing 3200 point data;

[0017] Pitch angle correction is performed on the two sets of data, and the upper surface original contour data Line A and the lower surface original contour data Line B are corrected to the same plane to obtain the upper surface contour data Line C and the lower surface contour data Line D;

[0018] Align the blade upper surface profile data Line C and the blade lower surface profile data Line D in the direction from the trailing edge to the leading edge;

[0019] If there is a gap at the end of the two contour data after alignment, the gap is fitted and supplemented with data to obtain the upper surface contour data Line E and the lower surface contour data Line F.

[0020] Furthermore, after obtaining the upper surface contour data Line E and the lower surface contour data Line F, the method further includes:

[0021] The center point H is obtained by averaging the first data of the leading end of contour Line E and the first data of the leading end of contour Line F, and the center point R is obtained by averaging the tail data of the trailing end of contour Line E and the tail data of the trailing end of contour Line F. The Euclidean distance between the center points H and R is calculated to obtain the section chord length.

[0022] Furthermore, after obtaining the upper surface contour data Line E and the lower surface contour data Line F, the method further includes:

[0023] Calculate the direction of the line connecting the center point H and the center point R;

[0024] A rectangle with a specified angle is enclosed for the blade profile in this direction, and the width of the obtained rectangle is the maximum thickness of the airfoil at the measurement position.

[0025] Furthermore, after obtaining the upper surface contour data Line E and the lower surface contour data Line F, the method further includes:

[0026] Calculate the direction of the line connecting the center point H and the center point R;

[0027] This direction is compared with the reference direction, and the angle between the two directions is taken as the section torsion angle at that location.

[0028] Furthermore, the gap position is fitted with supplementary data, including:

[0029] Select the vertical contour and endpoints to be completed;

[0030] Select 10 data points close to the endpoint;

[0031] Calculate the linear equation for these 10 data;

[0032] Extend the line until it is flush with the other contour;

[0033] Recalculate the positions of these 10 data;

[0034] Updates the outline data.

[0035] Furthermore, after obtaining the upper surface contour data Line E and the lower surface contour data Line F, the method further includes:

[0036] Determine the rear end point position information of the blade cross section;

[0037] The trailing edge area is delineated from the contour Line E and the contour Line F based on the rear endpoint, the extreme data is filtered out, and the remaining data is fitted with a rectangle. The width of the obtained rectangle is the trailing edge thickness.

[0038] Beneficial effects:

[0039] The device is simple and convenient to position, place and fix the product (blade). The entire measurement process adopts one-button operation, which reduces the contact between people and products, improves operation efficiency, reduces product quality risks, and avoids the inaccuracy of measurement caused by human factors. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is an axial view of the overall system device of the present invention;

[0041] Among them, 1-positioning tooling, 2-mobile ground rail, 3-robot auxiliary device, 4-line laser measuring instrument, 5-measurement system.

[0042] Figure 2 It is an axial view of the positioning tool of the present invention;

[0043] Among them, 11-leveling foot, 12-tooling platform, 13-contact positioning block, 14-guide, 15-calibration block.

[0044] Figure 3 It is an axial view of the mobile ground rail of the present invention; wherein, 21-leveling foot, 22-platform, 23-servo motor assembly, 24-gear transmission mechanism, 25-slide rail, 26-lubrication system, 27-flexible drag chain.

[0045] Figure 4 It is an axial view of the measuring system of the present invention; wherein 41 is a PLC control unit, 42 is a display, and 43 is an industrial computer.

[0046] Figure 5 It is an axial view of the robot auxiliary device of the present invention; wherein 51 is the robot body, 52 is the robot control cabinet, 53 is the mobile base, and 54 is the laser mounting bracket.

[0047] Figure 6 It is the overall system architecture diagram of the present invention.

[0048] Figure 7 Schematic diagram of the propeller root triangle area.

[0049] Figure 8 Schematic diagram of the errors between the spatial position, pitch angle, and traced line of the upper and lower sensors.

[0050] Fig. 9 This is a schematic diagram of the original contour data Line A and Line B.

[0051] Fig.10 Schematic diagram of contour Line C and contour Line D.

[0052] Fig.11 This is a schematic diagram of the contour data to be aligned.

[0053] Fig.12 Schematic diagram of the endpoint fitting of the contour data.

[0054] Fig.13 Schematic diagram of the cross-section chord length.

[0055] Fig.14 Schematic diagram of the circumscribed rectangle of the trailing edge thickness.

[0056] Fig.15 Schematic diagram of the circumscribed rectangle of the maximum thickness of the airfoil.

[0057] Fig.16 Schematic diagram of the cross-section torsion angle. DETAILED DESCRIPTION

[0058] Because the blade of the product being measured is relatively long, reaching more than 6 meters, and the surface is curved. This application needs to solve the measurement errors caused by the instability of human factors, such as: position error of the position to be measured, error caused by the non-perpendicularity of the contact surface between the measuring tool and the product, etc. Through the device developed this time, it is possible to accurately measure and calculate the thickness at the root of the blade, as well as the cross-sectional dimensions at a specified precise position, such as: trailing edge thickness, maximum airfoil thickness, chord length, and twist angle, etc.

[0059] like Figure 1 and Figure 6 As shown, a digital comprehensive detection system for helicopter composite blades is provided, which is mainly composed of a special positioning tool 1, a mobile ground track 2, a line laser measuring instrument 3, a measuring system 4, and a robot auxiliary device 5.

[0060] like Figure 2 As shown, 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.

[0061] 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.

[0062] like Figure 3 As shown, 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.

[0063] 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.

[0064] 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, and then combines and simulates the measured shape graphics. Then the algorithm calculates the relevant parameters required in the graphics. Figure 4 As shown, the measurement system includes: a PLC control unit 41, a display 42, and an industrial computer 43.

[0065] The robot auxiliary device 5 is used to clamp the line laser measuring instrument 3, and is installed as a whole on the movable ground rail 2. According to the needs, it can meet the needs of measuring any position of the product to be measured. Figure 5 As shown, the robot auxiliary device 5 includes: a robot body 51 , a robot control cabinet 52 , a mobile base 53 , and a laser mounting bracket 54 .

[0066] Specific measurement methods in the R&D measurement system:

[0067] ·Thickness of propeller root

[0068] In the area where the blade root thickness is measured, in the collected blade profile data, according to the required triangular area ( Figure 7 ) to filter the data and obtain the contour data within the specified triangular area and the contour data where the reference surface is located. Perform direction calculation and thickness calculation on each frame of the shape contour data, filter out the extreme contour data of some frames according to the set threshold, and calculate the average root thickness of the remaining frames, which is the thickness of the blade. Similarly, calculate the average angle to get the reference angle.

[0069] Section chord length

[0070] When the laser detection lines of the upper and lower surface sensors reach the measurement positions specified in the measurement task, the upper and lower measurement sensor controllers are triggered by the sensor command. After the controller responds, the callback function of its development kit is used to obtain the original contour data Line A and Line B, each containing 3200 point data. Due to the sensor installation error ( Figure 8 ), the upper and lower sensors have errors in spatial position, pitch angle, scanning line angle, etc., such as Fig. 9 shown.

[0071] After the pitch angle correction is performed on the two sets of data, the upper surface profile data Line C of the blade and the lower surface profile data Line D of the blade are obtained; Fig.10 shown.

[0072] In the direction from the trailing edge to the leading edge, align the upper surface profile data Line C of the blade and the lower surface profile data Line D of the blade. Fig.11 shown.

[0073] If two contour data are misaligned at the ends, the missing parts are fitted with supplementary data, so as to obtain the upper surface contour data Line E and the lower surface contour data Line F of the blade. The algorithm for fitting supplementary data is as follows: 1. Select the longitudinal contour to be completed and the endpoint; 2. Select 10 data close to the endpoint; 3. Calculate the linear equation of these 10 data; 4. Extend the straight line until it is flush with the other contour; 5. Recalculate the position of these 10 data; 6. Update the contour data. Fig.12 shown.

[0074] The center point H is obtained by averaging the first data of the leading edge of the contour Line E and the first data of the leading edge of the contour Line F, and the center point R is obtained by averaging the tail data of the trailing edge of the contour Line E and the tail data of the trailing edge of the contour Line F. The Euclidean distance between the front and rear end points is calculated using the coordinates (x1, y1, z1) and (x2, y2, z2) of two points in three-dimensional space, namely H and R, to obtain the chord length of the profile. Fig.13 shown.

[0075] Trailing edge thickness

[0076] At the measurement position required by the blade inspection, the rear endpoint position information of the blade section is obtained through the algorithm. After the trailing edge area is delineated based on the rear endpoint, the extreme data is filtered out and the remaining data is subjected to rectangular fitting. The obtained rectangle width is the trailing edge thickness. Fig.14 Similarly, the data of each frame is calculated, and the extreme contour data of some frames are filtered out according to the set threshold, and the mean value of the trailing edge thickness in the remaining frames is obtained, which is the final trailing edge thickness of the blade.

[0077] At the measurement position required by the blade detection, the algorithm is used to obtain the position information of the front and rear end points of the blade section, and the direction of the line connecting the two points is calculated. According to the direction, a rectangular enclosure of a specified angle is performed on the contour data, such as Fig.15 As shown, the width of the obtained rectangle is the maximum thickness of the airfoil at the measurement position.

[0078] Section twist angle

[0079] At the measuring position required for blade inspection, the position information of the front and rear end points of the blade section is obtained through the algorithm, the direction of the line connecting the two points is calculated, and the direction is compared with the reference direction (with the bushing end face as the reference), which is the section torsion angle at this location. Fig.16 shown.

[0080] Blade span

[0081] When the detection contour cannot be generated, its position information is recorded, and the final measurement position required for blade detection is tracked. The end of the blade shape is searched near this position along the X direction, and the position information is recorded and compared with the reference position, which is the blade extension.

Claims

1. A digital comprehensive detection system for helicopter composite blades, characterized in that: include: Special positioning tool (1), mobile ground rail (2), line laser measuring instrument (3), measuring system (4), robot auxiliary device (5); Two sets of special positioning tools (1) are rigidly connected to the mobile ground rail (2) to form an integral platform; a robot auxiliary device (5) is installed on the mobile ground rail (2) to achieve long-distance precise movement; a line laser measuring instrument (3) is clamped at the end of the robot auxiliary device (5) and cooperates with the mobile ground rail (2) to achieve long-distance or multi-directional scanning; the line laser measuring instrument (3) is used to scan the surface of the blade installed on the special positioning tool (1), and cooperates with the measurement system (4) to convert the measured data into a plane figure and calculate the required related parameters; The special positioning tool (1) comprises a first leveling foot (11), a tool platform (12), and a contour positioning block (13); the tool platform (12) is installed on the ground by adjusting the leveling foot and a nut, and the heights of a plurality of contour positioning blocks on the tool platform are adjusted to be on the same horizontal plane by adjusting the nut on the first leveling foot; a plurality of groups of mounting holes are provided on the tool platform (12) for mounting the contour positioning blocks; the contour positioning blocks are specially customized according to the shape of the outer surface of the leading edge of the blade, and the blade is placed upright along the length direction, and the portion in contact with the leading edge of the blade is made of a "soft" material to avoid scratching the outer surface of the blade; The mobile ground rail (2) comprises a second leveling foot (21), a platform (22), a servo system (23), a gear transmission mechanism (24), a slide rail (25), a lubrication system (26), and a flexible drag chain (27); A row of second leveling feet (21) is arranged at the lower part of one side of the platform (22), a slide rail (25) is installed on the platform, a servo system (23) is installed on two inner side walls of the platform, a servo system (23) is installed at one end of the slide rail (25), and the servo system (23) drives the robot auxiliary device (5) to slide on the slide rail (25) through a gear transmission mechanism (24); The platform is made of an integrated welded frame, and the gear and rack in the gear transmission mechanism are meshed in a helical manner; the platform is rigidly connected to the special positioning tool (1), and the second leveling foot is used to ensure that the adjustment planes between the two are parallel at the same level; The measuring length of the laser of the line laser measuring instrument (3) needs to be greater than the maximum length of a single cross section of the blade.

2. A digital comprehensive detection method for helicopter composite blades, using the digital comprehensive detection system for helicopter composite blades according to claim 1, characterized in that: The method includes: When a pair of laser detection lines of the line laser measuring instrument (3) respectively reach the measurement positions specified by the upper and lower surface measurement tasks of the blade, the callback function of the measurement system (4) is called to measure the upper surface original contour data Line A and the lower surface original contour data Line B, each containing 3200 point data; Pitch angle correction is performed on the two sets of data, and the upper surface original contour data Line A and the lower surface original contour data Line B are corrected to the same plane to obtain the upper surface contour data Line C and the lower surface contour data Line D; Align the blade upper surface profile data Line C and the blade lower surface profile data Line D in the direction from the trailing edge to the leading edge; If there is a gap at the end of the two contour data after alignment, the gap is fitted and supplemented with data to obtain the upper surface contour data Line E and the lower surface contour data Line F.

3. The method according to claim 2, characterized in that After obtaining the upper surface contour data Line E and the lower surface contour data Line F, the method further includes: The center point H is obtained by averaging the first data of the leading end of contour Line E and the first data of the leading end of contour Line F, and the center point R is obtained by averaging the tail data of the trailing end of contour Line E and the tail data of the trailing end of contour Line F. The Euclidean distance between the center points H and R is calculated to obtain the section chord length.

4. The method according to claim 2, characterized in that After obtaining the upper surface contour data Line E and the lower surface contour data Line F, the method further includes: Calculate the direction of the line connecting the center point H and the center point R; A rectangle with a specified angle is enclosed for the blade profile in this direction, and the width of the obtained rectangle is the maximum thickness of the airfoil at the measurement position.

5. The method according to claim 2, characterized in that: After obtaining the upper surface contour data Line E and the lower surface contour data Line F, the method further includes: Calculate the direction of the line connecting the center point H and the center point R; This direction is compared with the reference direction, and the angle between the two directions is taken as the section torsion angle at that location.

6. The method according to claim 2, characterized in that Fitting supplementary data for the gap site includes: Select the vertical contour and endpoints to be completed; Select 10 data points close to the endpoint; Calculate the linear equation for these 10 data; Extend the line until it is flush with the other contour; Recalculate the positions of these 10 data; Updates the outline data.

7. The method according to claim 2, characterized in that After obtaining the upper surface contour data Line E and the lower surface contour data Line F, the method further includes: Determine the rear end point position information of the blade cross section; The trailing edge area is delineated from the contour Line E and the contour Line F based on the rear endpoint, the extreme data is filtered out, and the remaining data is fitted with a rectangle. The width of the obtained rectangle is the trailing edge thickness.

8. A computer-readable storage medium comprising a computer program, characterized in that: When the program is executed by a processor, the method according to any one of claims 2 to 7 is implemented.

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