Engine attitude control method and engine lifting system

Abstract

The present application relates to a kind of engine posture control method and engine lifting system.The engine method includes the following steps:S1, the initial positioning of lifting positioner and the displacement sensor arranged thereon, the calibration of displacement sensor is calibrated;S2, engine mounting system and aircraft pylon arrangement calibration block, laser radar scans the position environment of engine mounting system and aircraft pylon, generates corresponding initial three-dimensional point cloud chart;S3, establish virtual coordinate system, calibration engine mounting system and the initial position of aircraft pylon;S4, based on initial position, the lifting path of engine is calculated.The present application proposes a kind of engine posture control method and engine lifting system, can effectively be replaced in wing, can effectively be replaced in wing, improves replacement accuracy and efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine replacement operation, and particularly relates to an engine posture adjusting control method and an engine lifting system. BACKGROUND

[0002] In the field of aero-engines, in order to ensure the continuous safe operation of an aircraft, when an engine fails or reaches a limited use condition, on-wing engine replacement work needs to be carried out. Due to the large weight and volume of the engine, the complex external layout, the small installation space and other reasons, the period of replacing the engine is long and the difficulty is great.

[0003] In the prior art, on-wing engine replacement needs to use guide tools, including thorn chains, tension pound tables and other tools, and the engine is lifted up or lowered down by tightening or loosening the thorn chains with a wrench. According to the investigation, it usually takes 8 people more than 6 hours to cooperatively operate to complete the on-wing engine replacement of one engine. The on-wing engine replacement process has strong dependence on the operating personnel, low work efficiency, poor reliability and safety hazards. SUMMARY

[0004] In view of the above problems of the prior art, the present application provides an engine posture adjusting control method and an engine lifting system, which can effectively realize on-wing engine replacement and improve the replacement accuracy and efficiency.

[0005] Specifically, the present application provides an engine posture adjusting control method suitable for on-wing engine replacement, comprising the following steps:

[0006] S1, initially positioning a lifting positioner and a displacement sensor arranged thereon, calibrating and demarcating the displacement sensor, and the lifting positioner is used to lift the engine to adjust the posture of the engine;

[0007] S2, arranging a demarcation block on the engine mounting system and the aircraft pylon, and scanning the position environment of the engine mounting system and the aircraft pylon by a laser radar to generate a corresponding initial three-dimensional point cloud map;

[0008] S3, establishing a virtual coordinate system, and demarcating the initial position of the engine mounting system and the aircraft pylon on the virtual coordinate system according to the initial three-dimensional point cloud map;

[0009] S4, calculating a lifting path of the engine based on the initial position, controlling the lifting positioner to lift the engine to a specified position according to the lifting path, and continuously scanning the position environment of the engine mounting system and the aircraft pylon by the laser radar during the lifting process, updating the three-dimensional point cloud map, and synchronously updating the lifting path based on the virtual coordinate system.

[0010] According to one embodiment of the present application, the aircraft pylon comprises an aircraft suspension and nacelle covers connected to the bottom of the aircraft suspension on both sides, the mounting system comprises engine process parts and front and rear mounting nodes arranged on the top of the engine process parts;

[0011] In step S2, first calibration blocks are arranged on the aircraft suspension and nacelle covers, second calibration blocks are arranged on the front and rear mounting nodes, and a laser radar is arranged on the top of each of the front and rear mounting nodes, and the laser radar scans the position environment of the mounting system and aircraft pylon based on the first and second calibration blocks.

[0012] According to one embodiment of the present application, at least 3 first calibration blocks are arranged in each of the two connection areas of the bottom of the aircraft suspension and the front and rear mounting nodes, and at least 9 first calibration blocks are arranged on the inner skin of each of the nacelle covers.

[0013] At least 2 second calibration blocks are arranged on the top of each of the front and rear mounting nodes.

[0014] According to one embodiment of the present application, 9 first calibration blocks are divided into 3 groups, each group has 3 first calibration blocks, and the 3 groups of first calibration blocks are uniformly distributed on the inner skin of each nacelle cover at a set angle a, and 30°≤ angle a ≤ 70°.

[0015] According to one embodiment of the present application, in step S2, the process of generating an initial three-dimensional point cloud image comprises:

[0016] The calibration and matching of left and right images of binocular vision are completed based on stereo vision technology and image processing technology, a stereo vision matching algorithm is used to complete the mapping from image coordinates to actual coordinates, the area of the marked region and the spatial coordinates of the feature points are calculated, and three-dimensional measurement and stereo reconstruction of the surface calibration blocks of the mounting system and aircraft pylon are realized.

[0017] According to one embodiment of the present application, in step S4, the optimized point cloud image is calculated by a KF-SLAM algorithm, comprising the steps of:

[0018] S41, determining the initial position and attitude information of the engine according to the first and second calibration blocks on the aircraft suspension and mounting system, and taking the data set M0;

[0019] S42, engine attitude measurement, calculating the theoretical position and attitude information of the engine based on the initial position and attitude information of the engine and the displacement data obtained by the displacement sensor on the lifting positioner, and calculating the data set M1;

[0020] S43, based on the real-time scanning of the first calibration block and the second calibration block by the laser radar to obtain the position information of the mounting system and the aircraft suspension, calculating the real-time position and attitude information of the engine as a data set M2;

[0021] S44, comparing and analyzing the data sets M1 and M2, if the data set setting condition is met, correlating the data sets M0, M1 and M2, continuously updating the three-dimensional point cloud map, and calculating and updating the lifting path.

[0022] According to one embodiment of the present application, the data set setting condition is |M1-M2|<10%×min{M1, M2}, if it is met, the lifting positioner is controlled to lift the engine to the specified position, and if it is not met, the lifting operation is stopped.

[0023] The present application also provides an engine lifting system suitable for the aforementioned engine attitude control method, comprising:

[0024] An engine lifting device, comprising a mounting bracket, four lifting positioners and four process adapters, the mounting bracket is used to carry the engine, the four lifting positioners include one lifting main positioner and three lifting auxiliary positioners, which are arranged at one corner of the mounting bracket respectively, each lifting positioner is connected with the mounting bracket through one process adapter, and each lifting positioner can move on the X / Y / Z axis of the engine to drive the engine to produce displacement through the process adapter;

[0025] A sensor group, comprising force sensors and displacement sensors, one force sensor is arranged on each lifting positioner to obtain the pulling force of the lifting positioner driving the process adapter, and multiple displacement sensors are arranged on each lifting positioner to detect the displacement of the lifting positioner on the X / Y / Z axis of the engine;

[0026] An electronic control unit is arranged on the lifting main positioner, the electronic control unit comprises a data acquisition control module and a calculation module, the data acquisition control module is used to receive the detection signals obtained by the sensor group and the scanning signals of the laser radar, the calculation module generates an initial three-dimensional point cloud map based on the scanning signals, and establishes a virtual coordinate system, and marks the initial positions of the engine mounting system and the aircraft suspension on the initial three-dimensional point cloud map, the calculation module calculates the lifting path of the engine based on the initial positions, and the electronic control unit realizes the 6-degree-of-freedom adjustment of the spatial attitude of the engine through the differential of the four lifting positioners based on the lifting path; wherein, during the lifting process, the data acquisition control module continuously receives the detection signals and the scanning signals, the calculation module continuously updates the three-dimensional point cloud map based on the detection signals and the scanning signals, and synchronously calculates the lifting path based on the virtual coordinate system.

[0027] According to an embodiment of the present invention, the signal from the displacement sensor received by the data acquisition control module should meet the displacement setting conditions. Multiple displacement sensors are arranged on each of the lifting positioners, and two displacement sensors are arranged in any axial direction of the X / Y / Z axis of the engine to detect the displacement of the lifting positioner on that axis and obtain displacement signals P1 and P2.

[0028] The displacement setting condition is as follows:

[0029] If signals P1 and P2 are normal and satisfy |P1-P2|<10%×min{P1,P2}, then the average value P3 of the signals is taken as the displacement value of the axis, P3=(P1+P2) / 2;

[0030] If either signal P1 or P2 is normal, then the normal signal is used as the displacement value of that axis.

[0031] If signals P1 and P2 are normal, and |P1-P2|≥10%×min{P1,P2}, then the displacement sensor needs to be calibrated.

[0032] If both P1 and P2 signals are abnormal, the corresponding displacement sensor needs to be replaced and calibrated.

[0033] According to one embodiment of the present invention, the signals from the force sensors received by the data acquisition and control module should meet the tension setting conditions. Let the four tension signals be F1, F2, F3, and F4, and the tension setting conditions be:

[0034] If max{F1, F2, F3, F4} - min{F1, F2, F3, F4} < 10% × min{F1, F2, F3, F4}, then the tension signal is normal.

[0035] If max{F1, F2, F3, F4} - min{F1, F2, F3, F4} ≥ 10% × min{F1, F2, F3, F4}, then the electronic control unit or data acquisition control module will trigger a safety alarm.

[0036] According to one embodiment of the present invention, each of the lifting positioners includes:

[0037] The base module includes a base assembly, a first slide rail, a first motor, and a motor mounting plate. The first slide rail is fixedly mounted on the base assembly, and the first motor is fixedly mounted on the motor mounting plate. The first motor is used to drive the motor mounting plate to move along the first slide rail.

[0038] The ram module includes a mounting plate assembly, a ram moving assembly, a second slide rail, a second motor, and a flexible connector. The second slide rail is fixed on the ram moving assembly, and the second motor is fixed on the mounting plate assembly. The second motor is used to drive the ram moving assembly to move along the length direction of the second slide rail. One end of the flexible connector is connected and fixed to the ram moving assembly, and the other end is connected and fixed to the process adapter.

[0039] The column module includes a column assembly, a third slide rail, a third motor, and a ball screw. The bottom of the column assembly is fixed to the motor mounting plate. The ball screw cooperates with the mounting plate assembly. The third motor is used to drive the ball screw to rotate, and the mounting plate assembly drives the entire ram module to move along the length direction of the third slide rail.

[0040] The length directions of the first, second, and third slide rails correspond to the X, Y, and Z directions of the engine.

[0041] According to one embodiment of the present invention, the calculation module solves for the specified position of the engine corresponding to the lifting path, decomposes the spatial position and attitude of the specified position into the movement stroke of each lifting positioner in the X / Y / Z axis direction, and drives the lifting positioners in a coordinated manner through the electronic control unit to make the engine reach the specified position.

[0042] According to one embodiment of the present invention, the lifting method of the engine includes single-point movement, linear movement, and nonlinear movement;

[0043] The single-point movement refers to the electronic control unit controlling a certain lifting positioner to move along the X-axis, Y-axis, or Z-axis according to actual needs.

[0044] The linear movement refers to the electronic control unit performing linear synchronous control of the three auxiliary lift positioners and the main lift positioner. The three-axis movement of the three auxiliary lift positioners is synchronized with the three-axis movement of the main lift positioner in a linear relationship so that the engine reaches the designated position at a set time.

[0045] The nonlinear movement refers to the electronic control unit performing nonlinear synchronous control on the three auxiliary lift positioners and the main lift positioner. The three-axis movement of the three auxiliary lift positioners is synchronized with the three-axis movement of the main lift positioner in a nonlinear relationship so that the engine reaches the designated position at a set time.

[0046] The electronic control unit calculates nonlinear movement parameters, which are then used to control the movement of the four lifting positioners. The nonlinear movement parameters are calculated based on a cam coupling 5-term formula, and the formulas for calculating position, velocity, and acceleration are as follows:

[0047] Location: f(x) = a0 + a1×x + a2×x^2 + a3×x^3 + a4×x^4 + a5×x^5;

[0048] Velocity: f'(x)=a1+2×a2×x+3×a3×x^2+4×a4×x^3+5×a5×x^4;

[0049] Acceleration: f(x) = 2 × a² + 6 × a³ × x + 12 × a⁴ × x² + 20 × a⁵ × x³;

[0050] Where x is time, f(x) is the position of a certain axis at a certain time point, velocity is the first derivative, acceleration is the second derivative, and a0~a5 are nonlinear translation parameters.

[0051] This invention provides an engine attitude control method and an engine lifting system that applies lidar SLAM to the on-wing engine replacement process of aero engines. It supplements the traditional positioning system composed of displacement sensors and force sensors during the on-wing engine replacement process. At the same time, it estimates the three-dimensional point cloud map of the engine attitude, aircraft pylon, and nacelle during the on-wing engine replacement process. The lidar SLAM is used to construct the engine movement path during the on-wing engine replacement process, thereby improving the positioning accuracy, safety, and overall efficiency of the on-wing engine replacement process.

[0052] It should be understood that the above general description and the following detailed description of the present invention are exemplary and illustrative, and are intended to provide further explanation of the present invention. Attached Figure Description

[0053] The accompanying drawings are included to provide a further understanding of the invention. They are incorporated in and constitute a part of this application. The drawings illustrate embodiments of the invention and, together with this specification, serve to explain the principles of the invention.

[0054] In the attached image:

[0055] Figure 1 A flowchart of an engine attitude control method according to an embodiment of the present invention is shown.

[0056] Figure 2 A schematic diagram of the structure of an aircraft pylon and mounting system according to an embodiment of the present invention is shown. Figure 1 .

[0057] Figure 3 A schematic diagram of the structure of an aircraft pylon and mounting system according to an embodiment of the present invention is shown. Figure 2 .

[0058] Figure 4 A schematic diagram of the structure of arranging a first calibration block on the nacelle cover according to an embodiment of the present invention is shown.Figure 1 .

[0059] Figure 5 A schematic diagram of the structure of arranging a first calibration block on the nacelle cover according to an embodiment of the present invention is shown. Figure 2 .

[0060] Figure 6 A schematic diagram of the structure of arranging a second calibration block on the front and rear mounting sections according to an embodiment of the present invention is shown.

[0061] Figure 7 A schematic diagram of an engine lifting system according to an embodiment of the present invention is shown.

[0062] Figure 8 A schematic diagram of the structure of a lifting positioner according to an embodiment of the present invention is shown.

[0063] Figure 9 A cross-sectional view of a lifting positioner according to an embodiment of the present invention is shown.

[0064] Figure 10 A schematic diagram of the structure of the base module of the lifting positioner according to an embodiment of the present invention is shown. Figure 1 .

[0065] Figure 11 A schematic diagram of the structure of the base module of the lifting positioner according to an embodiment of the present invention is shown. Figure 2 .

[0066] Figure 12 A schematic diagram of the ram module of a lifting positioner according to an embodiment of the present invention is shown. Figure 1 .

[0067] Figure 13 A schematic diagram of the ram module of a lifting positioner according to an embodiment of the present invention is shown. Figure 2 .

[0068] Figure 14 A schematic diagram of the column module of a lifting positioner according to an embodiment of the present invention is shown.

[0069] Figure 15 This is a schematic diagram of the principle of stereo vision.

[0070] The above figures include the following reference numerals:

[0071] Aircraft sling 501

[0072] Nacelle Cover 502

[0073] Engine process component 503

[0074] Front mounting section 504

[0075] Rear installation section 505

[0076] First calibration block 506

[0077] Second calibration block 507

[0078] LiDAR 508

[0079] Connection area 509

[0080] Engine lifting system 100

[0081] Mounting bracket 101

[0082] Lift Positioner 102

[0083] Lifting Master Positioner 1021

[0084] Lift Auxiliary Positioner 1022

[0085] Process adapter 103

[0086] Base module 200

[0087] Base assembly 201

[0088] First slide rail 202

[0089] First Motor 203

[0090] Motor mounting plate 204

[0091] First meshing rack 205

[0092] First slider 206

[0093] 207 moving wheels

[0094] First limiting block 208

[0095] First displacement sensor 209

[0096] 300 slide ram module

[0097] Mounting plate assembly 301

[0098] First horizontal board 3011

[0099] Second horizontal board 3012

[0100] Vertical board 3013

[0101] 302 Slide Bolt Moving Assembly

[0102] Second slide rail 303

[0103] Second motor 304

[0104] Flexible connector 305

[0105] Second meshing rack 306

[0106] Second slider 307

[0107] Second limiting block 308

[0108] Second displacement sensor 309

[0109] Screw limit block 310

[0110] Force sensor 311

[0111] Column Module 400

[0112] Column assembly 401

[0113] Third slide rail 402

[0114] Third motor 403

[0115] 404 ball screw

[0116] Third slider 405

[0117] Bearing 406

[0118] Third displacement sensor 407

[0119] Third limiting block 408 Detailed Implementation

[0120] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0121] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0122] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0123] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0124] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0125] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, rotated 90 degrees, or in other orientations, and the spatial relative descriptions used herein will be interpreted accordingly.

[0126] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0127] Figure 1 A flowchart of an engine attitude control method according to an embodiment of the present invention is shown. As shown, an engine attitude control method suitable for on-wing engine replacement includes the following steps:

[0128] S1, Initial positioning of the lifting positioner and the displacement sensor mounted on it, calibration and standardization of the displacement sensor, the lifting positioner is used to lift the engine to adjust the engine position.

[0129] S2, Layout calibration blocks on the engine mounting system and aircraft pylon, and generate corresponding initial three-dimensional point cloud maps based on the position environment of the engine mounting system and aircraft pylon scanned by the LiDAR of the calibration blocks.

[0130] S3. Establish a virtual coordinate system and mark the initial positions of the engine mounting system and aircraft pylon on the virtual coordinate system based on the initial 3D point cloud map.

[0131] S4 calculates the engine lifting path based on the initial position, and controls the lifting positioner to lift the engine to the designated position according to the lifting path. During the lifting process, the lidar continuously scans the position environment of the engine mounting system and the aircraft pylon, updates the three-dimensional point cloud map, and synchronously updates the lifting path based on the virtual coordinate system.

[0132] Figure 2 A schematic diagram of the structure of an aircraft pylon and mounting system according to an embodiment of the present invention is shown. Figure 1 . Figure 3 A schematic diagram of the structure of an aircraft pylon and mounting system according to an embodiment of the present invention is shown. Figure 2 . Figure 4 A schematic diagram of the structure of arranging a first calibration block on the nacelle cover according to an embodiment of the present invention is shown. Figure 1 . Figure 5 A schematic diagram of the structure of arranging a first calibration block on the nacelle cover according to an embodiment of the present invention is shown. Figure 2 . Figure 6A schematic diagram of the structure of the front and rear mounting sections arranged with second calibration blocks according to an embodiment of the present invention is shown. As shown, the aircraft pylon includes an aircraft pylon 501 and nacelle covers 502 connecting the bottom sides of the aircraft pylon 501. The mounting system includes an engine component 503 and a front mounting section 504 and a rear mounting section 505 disposed on top of the engine component 503. The mounting system is mounted on the engine. The ultimate purpose of lifting the engine is to align the mounting system with the aircraft pylon, suspending the engine at the bottom of the aircraft pylon, that is, to align the front mounting section 504 and the rear mounting section 505 upwards to the bottom of the aircraft pylon 501. Therefore, during the engine lifting process, engine attitude control is required.

[0133] In step S2, a first calibration block 506 is arranged on the aircraft pylon 501 and nacelle canopy 502, and a second calibration block 507 is arranged on the front mounting section 504 and rear mounting section 505. A lidar sensor 508 is arranged on the top of each of the front and rear mounting sections 505. The lidar sensor 508 scans the positional environment of the mounting system and the aircraft pylon based on the first and second calibration blocks 506 and 507, generating a corresponding initial 3D point cloud map. For ease of identification, the first and second calibration blocks 506 and 507 are preferably cubes, cylinders, or cuboids.

[0134] Better, refer to Figure 5 At least three first calibration blocks 506 are arranged in each of the two connection areas 509 at the bottom of the aircraft pylon 501 that align with the forward mounting section 504 and the aft mounting section 505. At least nine first calibration blocks 506 are arranged on the inner skin of each nacelle canopy 502. (Reference) Figure 6 At least two second calibration blocks 507 are arranged on the top of both the front mounting section 504 and the rear mounting section 505. The purpose of arranging a certain number of calibration blocks is to obtain a more accurate three-dimensional point cloud map and ensure the accuracy of subsequent calculations of the lifting path.

[0135] Better, refer to Figure 4 and Figure 5 The nine first calibration blocks 506 arranged on the nacelle cover 502 are divided into three groups of three. The three groups of first calibration blocks 506 are evenly distributed on the inner skin of each nacelle cover 502 at a set rotation angle α. Figure 4 As shown, a set of first calibration blocks 506 is provided at the bottom of the inner skin of the nacelle cover 502, and then another set of first calibration blocks 506 is provided upwards at intervals of α. A final set of first calibration blocks 506 is then provided upwards at intervals of α. (Reference) Figure 5 Each group of three first calibration blocks 506 is arranged along the engine X-axis and is evenly distributed along the axial length of the nacelle 502. The preferred rotation angle α is 30° ≤ rotation angle α ≤ 70°.

[0136] In step S2, the process of generating the initial 3D point cloud map includes: calibration and matching of the left and right binocular visual images based on stereo vision technology and image processing technology; mapping from image coordinates to actual coordinates using a stereo vision matching algorithm; calculating the area of ​​the marked region and the spatial coordinates of feature points to achieve 3D measurement and stereo reconstruction of the calibration block (position / calibration area) on the surface of the installation system and aircraft pylon. Specifically, this involves using a lidar scanner to scan the object itself, and based on the damage image parameters in the image coordinate system, using a stereo matching algorithm to combine the image coordinates of the image parameters with the actual physical coordinates of the image parameters to achieve 3D stereo reconstruction of the object's surface.

[0137] Stereo matching is the most crucial step in the parallax ranging process and also the most challenging problem in stereo vision. When a 3D scene is projected onto a 2D image, the same object will appear significantly different from different viewpoints. Furthermore, numerous factors, such as lighting conditions, noise interference, distortion, and camera characteristics, are all combined into a single grayscale value in the image. Additionally, previous preprocessing processes may further distort pixels. Therefore, achieving unambiguous and highly accurate stereo matching is extremely difficult.

[0138] Commonly used matching algorithms include correlation algorithms, relaxation algorithms, polyhedral correspondence algorithms, and correspondence algorithms for three-camera systems. A LiDAR 508 at the same location can emit two light sources, performing virtual 3D reconstruction of solid surfaces based on stereo vision principles. This allows for scanning and calculating the positions of calibration blocks (positions) on nacelle canopies and aircraft pylons. A preferred algorithm example is as follows:

[0139] Figure 15 This is a diagram illustrating the principle of stereo vision. As shown in the figure, based on the depth calculation principle of stereo vision, when the coordinate system is fixed at the optical center of the camera, we have:

[0140]

[0141] Two-dimensional coordinate information is converted into three-dimensional coordinate information. Where: (X, Y, Z) are the coordinates of the object point; (u1, v1) and (u2, v2) are the coordinates of the corresponding points of the object point on the left and right image planes, respectively; D = (u1 - u2) is the parallax. For two points M and N at a certain spatial distance L, their image points can be found on the left and right image planes through matching. When the focal length f is determined, the baseline distance b can be calculated.

[0142]

[0143] M and N are actual measurement points; key parameters are determined.

[0144] To convert the previously calculated image coordinate system to the physical coordinate system, the following formula can be used.

[0145]

[0146] Where: u, v are coordinates in the image coordinate system in pixels; x, y are physical coordinates in mm; u0, v0 are pixel coordinates at the intersection of the camera optical axis and the image plane, which is taken as the center of the adjusted image in the system; dx, dy are the scaling factors of the axes, which can be obtained by measurement.

[0147] After establishing the coordinate system, it is necessary to compare and measure the coordinates of the points in the image with those of the imaging points to calculate the degree of matching. For image f... L Given a point in (x, y), take a template T of size mxn centered at that point. Assume it moves Δx horizontally and Δy vertically. The template T covers the area f. R The k-th subgraph of (x,y) is S k If T and S k If they are the same, then their difference is 0. Define T and S. k The measure of the difference between them is:

[0148]

[0149] The coordinates of the midpoint in the image are compared and measured with those of the imaging point to calculate the degree of matching.

[0150] When D(T,S) k When T is at its minimum, T and S k To achieve the optimal match, the normalized cross-correlation function is defined as follows:

[0151]

[0152] When C(△x,△y) reaches its maximum, it indicates that the image point matches the imaging point.

[0153] Preferably, in step S4, the optimized point cloud map is calculated using the KF-SLAM (Kalman Filter - Simultaneous Localization and Mapping) algorithm, including the following steps:

[0154] S41, the initial position and attitude information of the engine are determined based on the aircraft pylon 501 and the first calibration block 506 and the second calibration block 507 on the installation system, and recorded as dataset M0;

[0155] S42, Engine Attitude Measurement: Based on the engine's initial position and attitude information, the theoretical position and attitude information of the engine are calculated using displacement data acquired by displacement sensors on the lifting positioner, resulting in dataset M1. It should be noted that displacement data is continuously acquired during the engine lifting process to calculate the engine's theoretical position and attitude information.

[0156] S43, based on the real-time scanning of the first calibration block 506 and the second calibration block 507 by the lidar 508, the position information of the mounting system and the aircraft pylon 501 is obtained, and the real-time position and attitude information of the engine is calculated, which is recorded as dataset M2. Similarly, during the engine lifting process, the first calibration block 506 and the second calibration block 507 are continuously scanned to obtain the position information of the mounting system and the aircraft pylon 501, and the real-time position and attitude information of the engine is calculated and updated.

[0157] S44. Compare and analyze datasets M1 and M2. If the dataset conditions are met, associate datasets M0, M1, and M2, continuously update the 3D point cloud map, and calculate and update the lifting path.

[0158] Applying KF-SLAM lidar to the on-wing engine replacement process creates a visualized laser-assisted positioning system. This complements traditional positioning systems composed of displacement sensors during the on-wing engine replacement process. Simultaneously, it estimates the engine's attitude, and the three-dimensional point cloud maps of the aircraft's pylon 501 and nacelle fairing 502. By constructing the engine's movement path (lift path) during the on-wing engine replacement process using KF-SLAM lidar, the positioning accuracy and safety of the on-wing engine replacement process can be improved.

[0159] Preferably, in step S44, the dataset setting condition is: |M1-M2|<10%×min{M1,M2}. If this condition is met, it indicates that the data is normal, and the lifting positioner is controlled to lift the engine to the designated position. If this condition is not met, it indicates that the data is abnormal, the lifting operation is stopped, and the sensors and lidar and other components need to be checked.

[0160] Figure 7 A schematic diagram of an engine lifting system according to an embodiment of the present invention is shown. Figure 8 A schematic diagram of the structure of a lifting positioner according to an embodiment of the present invention is shown. Figure 9 A cross-sectional view of a lifting positioner according to an embodiment of the present invention is shown. (Reference) Figure 7An engine lifting system 100, applicable to the aforementioned engine attitude control method, includes a mounting bracket 101, four lifting positioners 102, and four process adapters 103. The mounting bracket 101 supports the engine. The four lifting positioners 102 include one primary lifting positioner 1021 and three secondary lifting positioners 1022, each arranged at one corner of the mounting bracket 101. Each lifting positioner 102 is connected to the mounting bracket 101 via a process adapter 103. Each lifting positioner 102 is movable in the X / Y / Z axis directions of the engine to displace the engine via the process adapters 103.

[0161] Furthermore, the engine lifting system 100 also includes a sensor array. The sensor array includes force sensors and displacement sensors. A force sensor is arranged on each lifting positioner 102 to acquire the pulling force exerted by the lifting positioner 102 on the process adapter 103. Multiple displacement sensors are arranged on each lifting positioner 102 to detect the displacement of the lifting positioner in the X / Y / Z axis directions of the engine.

[0162] The engine lifting system 100 also includes an electronic control unit (not shown in the figure). This electronic control unit is located in the main lifting positioner 1021. The electronic control unit includes a data acquisition and control module and a calculation module. The data acquisition and control module receives detection signals from the sensor array and lidar scanning signals. The calculation module generates an initial 3D point cloud map based on the scanning signals and establishes a virtual coordinate system. It marks the initial positions of the engine mounting system and the aircraft pylon on the initial 3D point cloud map. Based on the initial positions, the calculation module calculates the engine lifting path. The electronic control unit, based on the lifting path, differentially adjusts the engine's spatial attitude using four lifting positioners 102 to achieve 6 degrees of freedom. Specifically, the calculation module calculates the output power of each lifting positioner 102 according to the lifting path, and the electronic control unit controls each lifting positioner 102 to operate synchronously according to this output power. During the lifting process, the data acquisition and control module continuously receives detection and scanning signals, and the calculation module continuously updates the 3D point cloud map based on the detection and scanning signals and synchronously calculates the lifting path based on the virtual coordinate system.

[0163] Preferably, the signals from the displacement sensors received by the data acquisition and control module should meet the displacement setting conditions. Multiple displacement sensors are arranged on each lifting positioner 102, with two displacement sensors arranged in any of the X / Y / Z axis directions of the engine to detect the displacement of the lifting positioner 102 on that axis, acquiring displacement signals P1 and P2. The displacement setting conditions are:

[0164] If signals P1 and P2 are normal and satisfy |P1-P2|<10%×min{P1,P2}, then the average value of the signals P3 is taken as the displacement value of the axis, P3=(P1+P2) / 2;

[0165] If either signal P1 or P2 is normal, then the normal signal P1 or P2 is used as the displacement value of that axis.

[0166] If signals P1 and P2 are normal, and |P1-P2|≥10%×min{P1,P2}, then the displacement sensor needs to be calibrated.

[0167] If both P1 and P2 signals are abnormal, the corresponding displacement sensor needs to be replaced and calibrated.

[0168] Based on the displacement setting conditions, displacement sensors with measurement errors are replaced or calibrated to ensure the lifting operation of the engine.

[0169] Preferably, the force sensor signals received by the data acquisition and control module should meet the tension setting conditions. Let the four tension signals be F1, F2, F3, and F4, and the tension setting conditions be:

[0170] If max{F1, F2, F3, F4} - min{F1, F2, F3, F4} < 10% × min{F1, F2, F3, F4}, then the tension signal is normal.

[0171] If max{F1, F2, F3, F4} - min{F1, F2, F3, F4} ≥ 10% × min{F1, F2, F3, F4}, then the electronic control unit or data acquisition control module will trigger a safety alarm.

[0172] Based on the tension setting conditions, ensure that the four lifting positioners 102 maintain tension balance during the lifting process to prevent the engine from overturning or tilting.

[0173] Better, refer to Figure 8 and Figure 9 Each lift positioner 102 includes a base module 200, a ram module 300, and a column module 400.

[0174] Figure 10 A schematic diagram of the structure of the base module of the lifting positioner according to an embodiment of the present invention is shown. Figure 1 . Figure 11 A schematic diagram of the structure of the base module of the lifting positioner according to an embodiment of the present invention is shown. Figure 2As shown in the figure, the base module 200 includes a base assembly 201, a first slide rail 202, a first motor 203, and a motor mounting plate 204. The first slide rail 202 is fixedly mounted on the base assembly 201. The first motor 203 is fixed on the motor mounting plate 204. The first motor 203 drives the motor mounting plate 204 to move along the first slide rail 202. It should be noted that... Figure 11 The motor mounting plate 204 was removed to facilitate observation of the internal structure.

[0175] Figure 12 A schematic diagram of the ram module of a lifting positioner according to an embodiment of the present invention is shown. Figure 1 . Figure 13 A schematic diagram of the ram module of a lifting positioner according to an embodiment of the present invention is shown. Figure 2 As shown in the figure, the ram module 300 includes a mounting plate assembly 301, a ram moving assembly 302, a second slide rail 303, a second motor 304, and a flexible connector 305. The second slide rail 303 is fixed to the ram moving assembly 302. The second motor 304 is fixed to the mounting plate assembly 301. The second motor 304 drives the ram moving assembly 302 to move along the length of the second slide rail 303. One end of the flexible connector 305 is connected and fixed to the ram moving assembly 302, and the other end is connected and fixed to the process adapter 103.

[0176] Figure 14 A schematic diagram of the column module of a lifting positioner according to an embodiment of the present invention is shown. (Combined with...) Figure 9 As shown, the column module 400 includes a column assembly 401, a third slide rail 402 in the vertical direction, a third motor 403, and a ball screw 404. The bottom of the column assembly 401 is fixed to the motor mounting plate 204, meaning that the entire column module 400 can move along the first slide rail 202 following the motor mounting plate 204. The ball screw 404 is arranged vertically and is threadedly engaged with the mounting plate assembly 301. The third motor 403 drives the ball screw 404 to rotate, and the ball screw 404 drives the entire ram module 300 to move along the length of the third slide rail 402 via the mounting plate assembly 301.

[0177] The length directions of the first slide rail 202, the second slide rail 303, and the third slide rail 402 correspond to the X, Y, and Z directions of the engine. The aircraft heading is the X-axis, the aircraft vertical is the Y-axis, and the aircraft span is the Z-axis, all consistent with the X / Y / X-axis directions of the engine. It is easy to understand that the lift positioner 102, through the first motor 203, the second motor 304, and the third motor 403, controls the movement of the ram moving assembly 302 in the ram module 300 in the X / Y / X-axis directions. The flexible connector 305 connects the ram moving assembly 302 and the process transfer component 103. Therefore, the lift positioner 102 can displace the process transfer component 103 through the ram moving assembly 302, and the synchronous operation of the four lift positioners 102 can drive the engine mounted on the mounting bracket 101 to adjust its attitude to achieve the installation position. The movement of the lifting and positioning device 102 in the X / Y / X-axis direction, as described below, refers to the lifting and positioning device 102 controlling the movement of the ram moving assembly 302 in the X / Y / X-axis direction, thereby acting on the process transfer component 103 through the flexible connector 305. Since the lifting and positioning device 102 is driven by a motor, it can replace the complex method of manually tightening the ratchet chain with a wrench in the prior art to lift the engine, greatly saving manpower, improving work efficiency in the engine replacement process, and reducing safety hazards.

[0178] Better, refer to Figure 11 The base module 200 also includes a first meshing rack 205 and a first slider 206. The first meshing rack 205 is fixedly mounted on the base assembly 201, and its length direction is consistent with the first slide rail 202. The first slider 206 is fixedly mounted on the motor mounting plate 204, and the first slider 206 slides in cooperation with the first slide rail 202. The output end of the first motor 203 engages with the first meshing rack 205. When the first motor 203 is started, it moves along the length direction of the first meshing rack 205 under the action of the first meshing rack 205, thereby driving the motor mounting plate 204 to move along the first slide rail 202 under the cooperation of the first slider 206 and the first slide rail 202. In this embodiment, two parallel first slide rails 202 and four first sliders 206 are arranged to ensure smooth movement of the motor mounting plate 204 on the X-axis. More preferably, a moving wheel 207 is provided on one side of the bottom of the base assembly 201 to facilitate moving the entire lifting and positioning device 102 to a designated location.

[0179] Preferably, the base module 200 further includes a first limiting block 208 and a first displacement sensor 209 disposed on the base assembly 201. The first limiting block 208 has an anti-collision sensor, and the first limiting block 208 and the first displacement sensor 209 are combined to limit the displacement of the motor mounting plate 204 to prevent the column module 400 from colliding when it moves along the X-axis, thereby avoiding the engine from overturning or tilting and affecting the lifting operation.

[0180] Better, refer to Figure 12 and Figure 13 The ram module 300 also includes a second meshing rack 306 and a second slider 307. The second meshing rack 306 is fixedly mounted on the bottom surface of the ram moving assembly 302. The second slider 307 is fixedly mounted on the mounting plate assembly 301 and slides in cooperation with the second slide rail 303. The output end of the second motor 304 engages with the second meshing rack 306. When the second motor 304 is started, under the action of the meshing rack and with the cooperation of the second slider 307 and the second slide rail 303, the ram moving assembly 302 can move in the Y-axis direction. Specifically, the mounting plate assembly 301 is riveted or welded together from a first horizontal plate 3011, a second horizontal plate 3012, and a vertical plate 3013. The second motor 304 is located at the bottom of the second horizontal plate 3012, and the second slider 307 is located on the bottom surface of the first horizontal plate 3011. The ram moving assembly 302 passes through the vertical plate 3013.

[0181] Preferably, the ram module 300 further includes a second limiting block 308 disposed on the ram moving assembly 302, and a second displacement sensor 309 disposed on the mounting plate assembly 301. The second limiting block 308 has an anti-collision sensor, and the combination of the second limiting block 308 and the second displacement sensor 309 is used to limit the displacement of the ram moving assembly 302 to prevent collisions when the ram moving assembly 302 moves along the Y-axis, thereby avoiding engine rollover or tilting, which would affect the lifting operation.

[0182] Preferably, the ram module 300 further includes a lead screw limiting block 310 disposed on the ram moving assembly 302. The lead screw limiting block 310 has a hollow structure, its outer side is fixedly connected to the mounting plate assembly 301, and its inner side is threaded into and engaged with a ball screw 404. The ball screw 404 drives the mounting plate assembly 301 and the ram moving assembly 302 to move along the length direction of the third slide rail 402 through the lead screw limiting block 310.

[0183] Preferably, the ram module 300 also includes a force sensor 311, which is disposed on the flexible connector 305 and used to detect the tensile force borne by the flexible connector 305. Using the flexible connector 305 avoids a rigid connection between the ram moving assembly 302 and the process adapter 103. The force sensor 311 obtains the tensile force value (tensile force signal) to ensure that the tensile force of the four flexible connectors 305 remains balanced, i.e., it needs to meet the aforementioned tensile force setting conditions for the four tensile force signals.

[0184] refer to Figure 13 and Figure 9The column module 400 also includes a third slider 405 and a bearing 406. The third slider 405 is slidably engaged with the third slide rail 402. The third slider 405 is fixed to the vertical plate 3013 of the mounting plate assembly 301. The ball screw 404 is fixed to the column assembly 401 via the bearing 406. The slidable engagement between the third slider 405 and the third slide rail 402 ensures smooth movement of the ram module 300 in the direction of the third slide rail 402.

[0185] Better, refer to Figures 11 to 13 The column module 400 also includes a third displacement sensor 407 and a third limiting block 408. The third displacement sensor 407 is mounted on the column assembly 401, and the third limiting block 408 is mounted on the mounting plate assembly 301. The third limiting block 408 has an anti-collision sensor. The third limiting block 408 and the third displacement sensor 407 are combined to limit the displacement of the ram module 300 in the length direction of the third slide rail 402, so as to prevent the ram moving assembly 302 from colliding when it moves on the Z-axis, and avoid the engine from overturning or tilting, thereby affecting the lifting operation. It should be noted that each lifting positioner 102 needs to be provided with two first limiting blocks 208 and two first displacement sensors 209 in the X-axis direction, two limiting blocks 308 and two second displacement sensors 309 in the Y-axis direction, and two third limiting blocks 408 and two third displacement sensors 407 in the Z-axis direction. The combination of the limit block and the displacement sensor is used to detect the displacement of the slide moving assembly 302 of the lifting positioner 102 in the X / Y / X axis direction, and the acquisition of the displacement signal should meet the aforementioned displacement setting conditions.

[0186] To put it simply, the aircraft's heading is the X-axis, its vertical direction is the Y-axis, its span is the Z-axis, rotation around the X-axis is angle α, rotation around the Y-axis is angle β, and rotation around the Z-axis is angle γ. The electronic control unit (ECU) uses four lift positioners 102 to differentially adjust the engine's spatial attitude with six degrees of freedom (DOF). These six DEFs are the translational degrees of freedom along the X, Y, and Z axes and the rotational degrees of freedom around these axes. Engine attitude control is achieved by a calculation module that uses the Jacobian matrix to solve for the engine's designated position along the lift path. The spatial position and attitude of the designated position are decomposed into the travel distance of each lift positioner 102 along the X, Y, and Z axes. The calculation module calculates the output power of each lift positioner 102 based on the travel distance, and the ECU synchronously drives the lift positioners 102 to achieve the designated position.

[0187] Preferably, the lifting positioner 102 lifts the engine in three ways: single-point movement, linear movement, and non-linear movement, in order to achieve precise adjustment of the engine's position and spatial attitude.

[0188] Single-point movement refers to the electronic control unit controlling a specific lifting positioner 102 to move along the X-axis, Y-axis, or Z-axis according to actual needs. Single-point movement can include operations such as positioning, stopping, emergency stop, brake release, and zero-point reset.

[0189] Linear movement refers to the electronic control unit's linear synchronous control of the three auxiliary lift positioners 1022 and the main lift positioner 1021. The three-axis movement of the three auxiliary lift positioners 1022 is synchronized with the three-axis movement of the main lift positioner 1021 in a linear relationship so that the engine reaches the designated position at a set time.

[0190] Nonlinear movement refers to the electronic control unit performing nonlinear synchronous control on the three lifting auxiliary positioners 1022 and the lifting main positioner 1021. The three-axis movement of the three lifting auxiliary positioners 1022 is synchronized with the three-axis movement of the lifting main positioner 1021 in a nonlinear relationship so that the engine reaches the designated position at a set time.

[0191] The calculation module calculates the nonlinear movement parameters, which the electronic control unit uses to control the movement of the four lifting positioners 102. The nonlinear movement parameters (cam synchronization coefficient) are calculated based on the cam coupling five-term formula. The formulas for calculating position, velocity, and acceleration are as follows:

[0192] Location: f(x) = a0 + a1×x + a2×x^2 + a3×x^3 + a4×x^4 + a5×x^5;

[0193] Velocity: f'(x)=a1+2×a2×x+3×a3×x^2+4×a4×x^3+5×a5×x^4;

[0194] Acceleration: f(x) = 2 × a² + 6 × a³ × x + 12 × a⁴ × x² + 20 × a⁵ × x³;

[0195] Where x is time, f(x) is the position of a certain axis at a certain time point, velocity is the first derivative, acceleration is the second derivative, and a0~a5 are the nonlinear movement parameters to be solved.

[0196] It will be apparent to those skilled in the art that various modifications and variations can be made to the exemplary embodiments described above without departing from the spirit and scope of the invention. Therefore, it is intended that this invention cover modifications and variations falling within the scope of the appended claims and their equivalents.

Claims

1. An engine attitude control method, applicable to on-wing engine replacement, comprising the following steps: S1, Initial positioning of the lifting positioner and the displacement sensor mounted thereon is performed, and the displacement sensor is calibrated and set. The lifting positioner is used to lift the engine to adjust the engine's position and orientation. S2, calibration blocks are arranged on the engine mounting system and the aircraft pylon, and the lidar scans the position environment of the engine mounting system and the aircraft pylon to generate the corresponding initial three-dimensional point cloud map; S3, Establish a virtual coordinate system, and mark the initial positions of the engine mounting system and the aircraft pylon on the virtual coordinate system according to the initial three-dimensional point cloud map; S4. Calculate the engine lifting path based on the initial position, and control the lifting positioner to lift the engine to the designated position according to the lifting path. During the lifting process, the lidar continuously scans the position environment of the engine mounting system and the aircraft pylon, updates the three-dimensional point cloud map, and synchronously updates the lifting path based on the virtual coordinate system.

2. The engine attitude control method as described in claim 1, characterized in that, The aircraft pylon includes an aircraft pylon and a nacelle canopy connecting the bottom sides of the aircraft pylon; the mounting system includes an engine component and a front mounting section and a rear mounting section disposed on top of the engine component. In step S2, a first calibration block is arranged on the aircraft pylon and nacelle canopy, a second calibration block is arranged on the front and rear mounting sections, and a lidar is arranged on the top of each of the front and rear mounting sections. The lidar scans the positional environment of the mounting system and the aircraft pylon based on the first and second calibration blocks.

3. The engine attitude control method as described in claim 2, characterized in that, At least three first calibration blocks are arranged in each of the two connection areas at the bottom of the aircraft pylon that are aligned with the front and rear mounting sections, and at least nine first calibration blocks are arranged on the inner skin of each nacelle. At least two of the second calibration blocks are arranged on the top of both the front and rear mounting sections.

4. The engine attitude control method as described in claim 3, characterized in that, The nine first calibration blocks are divided into three groups of three. The three groups of first calibration blocks are evenly distributed on the inner skin of each nacelle at a set rotation angle α, and 30°≤ rotation angle α≤70°.

5. The engine attitude control method as described in claim 1, characterized in that, In step S2, the process of generating the initial 3D point cloud map includes: Based on stereo vision technology and image processing technology, the calibration and matching of the left and right images of binocular vision are completed; a stereo vision matching algorithm is used to complete the mapping from image coordinates to actual coordinates; the area of ​​the marked region and the spatial coordinates of feature points are calculated to realize the three-dimensional measurement and stereo reconstruction of the calibration block on the surface of the installation system and the aircraft pylon.

6. The engine attitude control method as described in claim 2, characterized in that, In step S4, the optimized point cloud map is calculated using the KF-SLAM algorithm, including the following steps: S41, the initial position and attitude information of the engine are determined based on the first calibration block and the second calibration block on the aircraft sling and mounting system, and recorded as dataset M0; S42, Engine attitude measurement: Based on the initial position and attitude information of the engine, the theoretical position and attitude information of the engine are calculated by using displacement data obtained by displacement sensors on the lifting positioner, and the dataset M1 is calculated. S43, based on the real-time scanning of the first calibration block and the second calibration block by the lidar, obtain the position information of the installation system and the aircraft sling, calculate the real-time position and attitude information of the engine, and record it as dataset M2; S44. Compare and analyze datasets M1 and M2. If the dataset conditions are met, associate datasets M0, M1, and M2, continuously update the 3D point cloud map, and calculate and update the lifting path.

7. The engine attitude control method as described in claim 6, characterized in that, The dataset is set with the condition: |M1-M2|<10%×min{M1,M2}. If this condition is met, the lifting positioner is controlled to lift the engine to the designated position. If this condition is not met, the lifting operation is stopped.

8. An engine lifting system, applicable to the engine attitude control method according to any one of claims 1-7, characterized in that, include: An engine lifting device includes a mounting bracket, four lifting positioners, and four process adapters. The mounting bracket is used to support the engine. The four lifting positioners include one main lifting positioner and three auxiliary lifting positioners, which are respectively arranged at one corner of the mounting bracket. Each lifting positioner is connected to the mounting bracket through one of the process adapters. Each lifting positioner can move on the X / Y / Z axes of the engine to drive the engine to generate displacement through the process adapters. The sensor group includes force sensors and displacement sensors. One force sensor is arranged on each of the lifting positioners to obtain the pulling force of the lifting positioner driving the process adapter. Multiple displacement sensors are arranged on each of the lifting positioners to detect the displacement of the lifting positioner on the X / Y / Z axes of the engine. An electronic control unit (ECU) is located at the lifting master positioner. The ECU includes a data acquisition and control module and a calculation module. The data acquisition and control module receives detection signals from the sensor group and scanning signals from the lidar. The calculation module generates an initial 3D point cloud map based on the scanning signals and establishes a virtual coordinate system. It marks the initial positions of the engine mounting system and the aircraft pylon on the initial 3D point cloud map. The calculation module calculates the lifting path of the engine based on the initial positions. The ECU adjusts the engine's spatial attitude in six degrees of freedom using the differential movement of the four lifting positioners based on the lifting path. During the lifting process, the data acquisition and control module continuously receives detection and scanning signals, and the calculation module continuously updates the 3D point cloud map based on the detection and scanning signals and synchronously calculates the lifting path based on the virtual coordinate system.

9. The engine lifting system as described in claim 8, characterized in that, The signals from the displacement sensors received by the data acquisition and control module should meet the displacement setting conditions. Multiple displacement sensors are arranged on each of the lifting positioners, and two displacement sensors are arranged in any axial direction of the X / Y / Z axis of the engine to detect the displacement of the lifting positioner on that axis and obtain displacement signals P1 and P2. The displacement setting condition is as follows: If signals P1 and P2 are normal and satisfy |P1-P2|<10%×min{P1,P2}, then the average value P3 of the signals is taken as the displacement value of the axis, P3=(P1+P2) / 2; If either signal P1 or P2 is normal, then the normal signal is used as the displacement value of that axis. If signals P1 and P2 are normal, and |P1-P2|≥10%×min{P1,P2}, then the displacement sensor needs to be calibrated. If both P1 and P2 signals are abnormal, the corresponding displacement sensor needs to be replaced and calibrated.

10. The engine lifting system as described in claim 8, characterized in that, The signals from the force sensors received by the data acquisition and control module should meet the tension setting conditions. Let the four tension signals be F1, F2, F3, and F4. The tension setting conditions are as follows: If max{F1, F2, F3, F4} - min{F1, F2, F3, F4} < 10% × min{F1, F2, F3, F4}, then the tension signal is normal. If max{F1, F2, F3, F4} - min{F1, F2, F3, F4} ≥ 10% × min{F1, F2, F3, F4}, then the electronic control unit or data acquisition control module will trigger a safety alarm.

11. The engine lifting system as described in claim 8, characterized in that, Each of the lifting positioners includes: The base module includes a base assembly, a first slide rail, a first motor, and a motor mounting plate. The first slide rail is fixedly mounted on the base assembly, and the first motor is fixedly mounted on the motor mounting plate. The first motor is used to drive the motor mounting plate to move along the first slide rail. The ram module includes a mounting plate assembly, a ram moving assembly, a second slide rail, a second motor, and a flexible connector. The second slide rail is fixed on the ram moving assembly, and the second motor is fixed on the mounting plate assembly. The second motor is used to drive the ram moving assembly to move along the length direction of the second slide rail. One end of the flexible connector is connected and fixed to the ram moving assembly, and the other end is connected and fixed to the process adapter. The column module includes a column assembly, a third slide rail, a third motor, and a ball screw. The bottom of the column assembly is fixed to the motor mounting plate. The ball screw cooperates with the mounting plate assembly. The third motor is used to drive the ball screw to rotate, and the mounting plate assembly drives the entire ram module to move along the length direction of the third slide rail. The length directions of the first, second, and third slide rails correspond to the X, Y, and Z directions of the engine.

12. The engine lifting system as described in claim 8, characterized in that, The calculation module solves for the specified position of the engine corresponding to the lifting path, decomposes the spatial position and attitude of the specified position into the movement stroke of each lifting positioner in the X / Y / Z axis directions, and drives the lifting positioners in a coordinated manner through the electronic control unit so that the engine reaches the specified position.

13. The engine lifting system as described in claim 12, characterized in that, The lifting methods for the engine include single-point movement, linear movement, and non-linear movement; The single-point movement refers to the electronic control unit controlling a certain lifting positioner to move along the X-axis, Y-axis, or Z-axis according to actual needs. The linear movement refers to the electronic control unit performing linear synchronous control of the three auxiliary lift positioners and the main lift positioner. The three-axis movement of the three auxiliary lift positioners is synchronized with the three-axis movement of the main lift positioner in a linear relationship so that the engine reaches the designated position at a set time. The nonlinear movement refers to the electronic control unit performing nonlinear synchronous control on the three auxiliary lift positioners and the main lift positioner. The three-axis movement of the three auxiliary lift positioners is synchronized with the three-axis movement of the main lift positioner in a nonlinear relationship so that the engine reaches the designated position at a set time. The electronic control unit calculates nonlinear movement parameters, which are then used to control the movement of the four lifting positioners. The nonlinear movement parameters are calculated based on a cam coupling 5-term formula, and the formulas for calculating position, velocity, and acceleration are as follows: Location: f(x) = a0 + a1×x + a2×x^2 + a3×x^3 + a4×x^4 + a5×x^5; Velocity: f'(x) = a1 + 2×a2×x + 3×a3×x^2 + 4×a4×x^3 + 5×a5×x^4; Acceleration: f''(x) = 2×a² + 6×a³×x + 12×a⁴×x² + 20×a⁵×x³; Where x is time, f(x) is the position of a certain axis at a certain time point, velocity is the first derivative, acceleration is the second derivative, and a0~a5 are nonlinear translation parameters.

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