A detection method and detection device for high-precision propellers

Abstract

The application discloses a kind of detection method and detection device of high-precision propeller, it is related to propeller detection technical field, for the deviation that present manual measurement can appear because person uses caliper etc., and time-consuming and labor-consuming.Moreover, the problem that the use space requirement is higher is solved by using three-coordinate measuring machine which is expensive and cumbersome equipment, and the following scheme is presented, which comprises the following steps: S1: obtaining the measurement point cloud of propeller, filtering the measurement point cloud to obtain the target point cloud;S2: the first measurement plane is obtained by processing the target point cloud, and the center point of the pressure cone point cloud is found;S3: the measurement axis is obtained according to the first measurement plane and the center point;S4: the target point cloud is segmented to obtain the blade point cloud of each blade, and the parameters of the propeller are obtained by analyzing the blade point cloud and the measurement axis to determine whether the propeller is qualified, the parameters of the propeller are obtained by analyzing the blade point cloud and the measurement axis to determine whether the propeller is qualified.

Description

Technical Field

[0001] This invention relates to the field of propeller testing technology, and in particular to a high-precision propeller testing method and device. Background Technology

[0002] A propeller is a device that converts engine power into propulsion by rotating blades in air or water. It can have two or more blades connected to a hub, and the rearward-facing surface of the blades is a helical surface or a near-helical surface. Propellers come in many types and have a wide range of applications, such as propulsion systems for airplanes and ships. The blades are the core of the propeller's power, and the manufacturing quality of the propeller blades directly affects the propeller's performance and lifespan. High-precision blade inspection is not only the basis for judging whether the blades are qualified, but also an important part of quality control in the manufacturing process.

[0003] Traditional propeller inspection methods mainly include: 1. manual measurement using calipers; 2. contact point measurement using a coordinate measuring machine. Both methods have obvious drawbacks. Manual measurement is prone to errors due to the use of calipers and other tools, and is also time-consuming and labor-intensive. Using a coordinate measuring machine is expensive, bulky, and requires a large amount of space.

[0004] Therefore, overcoming the shortcomings of the existing technology is a problem that needs to be solved in this technical field. Summary of the Invention

[0005] The present invention proposes a high-precision propeller detection method and device, which mainly solves the technical problem of using a high-precision structured light 3D camera and a convenient, portable, simple and high-precision detection scheme for propeller products developed based on the open-source 3D algorithm framework PCL. The portable and labor-saving measurement device can also improve detection efficiency and the feasibility of promotion.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A high-precision propeller testing method includes the following steps:

[0008] S1: Obtain the measurement point cloud of the propeller, and filter the measurement point cloud to obtain the target point cloud;

[0009] S2: Process the target point cloud to obtain the first measurement plane, and find the center point of the cone point cloud;

[0010] S3: Obtain the measurement axis based on the first measurement plane and the center point;

[0011] S4: Segment the target point cloud to obtain the blade point cloud of each blade, analyze the blade point cloud and the measurement axis to obtain various parameters of the propeller, and determine whether the propeller is qualified.

[0012] Preferably, the step of acquiring the measurement point cloud of the propeller and filtering the measurement point cloud to obtain the target point cloud includes:

[0013] A structured light 3D camera is used to detect the propeller and obtain the measurement point cloud of the propeller;

[0014] The measured point cloud is filtered to remove stray point clouds and obtain the target point cloud.

[0015] Preferably, the process of processing the target point cloud to obtain the first measurement plane includes:

[0016] Three non-collinear points are randomly selected from the target point cloud, and a plane is defined by these three points.

[0017] Find in-place points from the target point cloud, wherein points whose distance to the plane is less than a preset distance are considered in-place points;

[0018] Update the three points selected in step A, redefine a plane, and execute step B to obtain the in-place points of the updated plane;

[0019] In iterative processing step C, after a preset number of iterations, the plane with the most local points is selected as the first measurement plane.

[0020] Preferably, obtaining the measurement axis based on the first measurement plane and the center point includes:

[0021] Based on the center point of the pressure cone point cloud and the normal vector of the first measurement plane, the equation of the measurement axis line is obtained;

[0022] The equation of the symmetrical measurement axis line is converted into the equation of the intersecting surface measurement axis line to obtain the measurement axis.

[0023] Preferably, the step of segmenting the target point cloud to obtain the blade point cloud for each blade, and analyzing the blade point cloud and the measurement axis to obtain various parameters of the propeller to determine whether the propeller is qualified includes:

[0024] The target point cloud is segmented to obtain the blade point cloud for each blade;

[0025] Calculate the distance value of each blade point cloud from the measurement axis, and add the blade point clouds whose distance values ​​meet the specific distance to the point set P;

[0026] Calculate the point P_max that is farthest from the first measurement plane in the point set P;

[0027] The distance from point P_max to the first measuring plane is taken as the blade height. The full pitch of the propeller is calculated according to the full pitch measurement formula to determine whether the blade height and full pitch meet the requirements.

[0028] Preferably, the step of segmenting the target point cloud to obtain the blade point cloud for each blade, and analyzing the blade point cloud and the measurement axis to obtain various parameters of the propeller to determine whether the propeller is qualified further includes:

[0029] Calculate the point P_min in the point set P that is closest to the first measurement plane;

[0030] Calculate the second measurement plane formed by point P_max and the measurement axis, and calculate the third measurement plane formed by point P_min and the measurement axis;

[0031] Calculate the target angle between the second and third measurement planes;

[0032] The second measurement plane is divided into n equal division planes based on the local equal division number n and the included angle of the target.

[0033] Calculate the local pitch based on the point set P and each equally divided plane.

[0034] Preferably, the step of dividing the second measuring plane into n equal division planes based on the local equal division n and the target angle includes: rotating the second measuring plane around the measuring axis by 1 / n times, 2 / n times, ..., (n-1) / n times the target angle based on the local equal division n to obtain n equal division planes.

[0035] Preferably, the calculation of the local pitch based on the point set P and each equally divided plane includes:

[0036] Calculate the intersection points of point set P with each equally divided plane, and use these intersection points as input for the local pitch. Calculate the local pitch based on the pitch calculation method and the intersection points to determine whether the local pitch meets the requirements.

[0037] Preferably, the step of segmenting the target point cloud to obtain the blade point cloud for each blade, and analyzing the blade point cloud and the measurement axis to obtain various parameters of the propeller to determine whether the propeller is qualified further includes:

[0038] Find the flange point P_invert, obtain the height difference between the flange point P_invert and point P_max perpendicular to the first measurement plane, and use this height difference as the flange height to determine whether the flange height meets the requirements.

[0039] A high-precision propeller testing device, the testing device comprising:

[0040] One or more processors, a memory, and one or more applications; wherein the one or more applications are stored in the memory and configured to be executed by the processor to implement the detection method described in this application.

[0041] The beneficial effects of this invention are:

[0042] This application provides a high-precision propeller detection method and device. The method involves acquiring a measurement point cloud of the propeller, filtering the measurement point cloud to obtain a target point cloud, processing the target point cloud to obtain a first measurement plane, and finding the center point of the pressure cone point cloud. A measurement axis is obtained based on the first measurement plane and the center point. The target point cloud is segmented to obtain the blade point cloud of each blade. Analysis of the blade point cloud and the measurement axis yields various parameters of the propeller to determine its qualification. This application employs a high-precision structured light 3D camera and a convenient, portable, and high-precision detection solution for propellers developed based on the open-source 3D algorithm framework PCL. The portable and labor-saving measurement equipment also improves detection efficiency and feasibility for widespread application. Attached Figure Description

[0043] Figure 1 This is a flowchart illustrating a high-precision propeller detection method provided in an embodiment of this application;

[0044] Figure 2 This is a flowchart illustrating another high-precision propeller detection method provided in an embodiment of this application;

[0045] Figure 3 This is a flowchart illustrating another high-precision propeller detection method provided in this application embodiment;

[0046] Figure 4 This is a flowchart illustrating another high-precision propeller detection method provided in this application embodiment;

[0047] Figure 5 This is a schematic diagram of the structure of a detection device provided in the application embodiment. Detailed Implementation

[0048] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0049] Example 1:

[0050] Based on years of in-depth research into the propeller industry, current blades exhibit significant spatial twist and complex cross-sectional shapes. Using traditional cylindrical coordinate measurement methods presents numerous problems, primarily in the following three aspects:

[0051] (1) Reliability issues: The traditional method uses a probe head that is a cone or a sphere. When measuring blades, the following situations may occur, which will affect the reliability of the measurement: First, the probe will interfere with the blade before reaching the designated measurement point; Second, due to structural and other factors, the probe cannot measure the designated measurement point.

[0052] (2) Accuracy issues: Because the blade pitch angle is large, the measuring rod is prone to offset on the blade surface when using traditional measurement methods, which seriously affects the measurement accuracy. In some scenarios, the accuracy is further affected by the presence of human intervention.

[0053] (3) High labor costs and low efficiency. Traditional methods rely on manpower to achieve detection, and the measurement cycle is slow and inefficient.

[0054] To address the aforementioned problems, this embodiment provides a high-precision propeller detection method. This method improves measurement reliability and accuracy, and is implemented in a time-saving and efficient manner. (See reference...) Figure 1 The detection method includes:

[0055] Step S1: Obtain the measurement point cloud of the propeller, and filter the measurement point cloud to obtain the target point cloud;

[0056] Step S2: Process the target point cloud to obtain the first measurement plane, and find the center point of the pressure cone point cloud;

[0057] Combination Figure 2 Step S1 specifically includes: using a structured light 3D camera to detect the propeller and obtain the measurement point cloud of the propeller; filtering the measurement point cloud to remove stray point clouds and obtain the target point cloud.

[0058] Step S2 specifically includes: Step A: Randomly select three non-collinear points from the target point cloud, and use these three points to determine a plane;

[0059] Step B: Find inliers from the target point cloud, where points whose distance to the plane is less than a preset distance are considered inliers;

[0060] Step C: Update the three points selected in Step A, redefine a plane, and execute Step B to obtain the interior points of the updated plane;

[0061] In iterative processing step C, after a preset number of iterations, the plane with the most local points is selected as the first measurement plane.

[0062] Specifically, the RANSAC method is used to fit the plane, and the specific principle is as follows:

[0063] Step 1: Randomly select three non-collinear points (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3) to define a plane.

[0064]

[0065] The second step is to find the local point and its distance from the upper plane. The point is taken as an in-place point; the distance from the point to the plane is obtained according to the following formula.

[0066]

[0067] The distance between two points is obtained using the following formula:

[0068]

[0069] in, and These are the coordinates of the two points.

[0070] The third step is to update the three points selected in the first step. Repeat these three steps, and each repetition is called an iteration.

[0071] Step 4: After iterating n times, select the plane with the most local points as the first measurement plane.

[0072] Find the center point of the pressure cone cloud using the following formula.

[0073]

[0074] Step S3: Obtain the measurement axis based on the first measurement plane and the center point;

[0075] In this embodiment, the equation of the measurement axis line is obtained based on the center point of the pressure cone point cloud and the normal vector of the first measurement plane; the symmetrical measurement axis line equation is converted into the intersecting plane measurement axis line equation to obtain the measurement axis.

[0076] Based on the center point of the cone point cloud and the normal vector of the first measurement plane, the equation of the straight line of the measurement axis is obtained: The measurement axis equation is transformed from a symmetric form to a surface form.

[0077] Step S4: Segment the target point cloud to obtain the blade point cloud of each blade, analyze the blade point cloud and the measurement axis to obtain various parameters of the propeller, and determine whether the propeller is qualified.

[0078] Combination Figure 3In this embodiment, the target point cloud is segmented to obtain the blade point cloud of each blade; the distance value of each blade point cloud from the measurement axis is calculated, and the blade point cloud with the distance value meeting the specific distance is added to the point set P; the point P_max farthest from the first measurement plane in the point set P is calculated; the distance from point P_max to the first measurement plane is taken as the blade height, and the full pitch of the propeller is calculated according to the full pitch measurement formula to determine whether the blade height and full pitch meet the requirements.

[0079] The distance from a point to a line is calculated using the following formula:

[0080]

[0081]

[0082]

[0083] In this embodiment, the blade height is calculated according to the following formula: based on the distance from the point to the plane, the distance between the point farthest from the measuring plane in the point set P and the measuring plane is calculated.

[0084] If it is necessary to inspect local pitch and flange height, the inspection can be carried out in the following manner, specifically, in conjunction with... Figure 4 Calculate the point P_min in the point set P that is closest to the first measurement plane; calculate the second measurement plane formed by point P_max and the measurement axis; calculate the third measurement plane formed by point P_min and the measurement axis; calculate the target angle between the second and third measurement planes; divide the second measurement plane into n equal division planes according to the local equal division number n and the target angle; calculate the local pitch according to the point set P and each equal division plane.

[0085] In this embodiment, the dividing planes are obtained as follows: based on the local division number n, the second measuring plane is rotated around the measuring axis by 1 / n times, 2 / n times... (n-1) / n times the target angle to obtain n dividing planes.

[0086] The calculation of local pitch based on point set P and each equally divided plane is as follows: calculate the intersection points of point set P with each equally divided plane, use the intersection points as input for local pitch, calculate the local pitch according to the pitch calculation method and the intersection points, and determine whether the local pitch meets the requirements.

[0087] In this embodiment, the included angle between the two planes is obtained according to the following formula:

[0088]

[0089] Based on the previous description, the method for calculating local pitch is briefly explained again below:

[0090] Step 1: Calculate the rotated bisecting surface, and determine the bisecting angle based on the local bisecting number n: First, let i=1; on Plane1 (the first measurement plane), arbitrarily select three non-collinear points, and translate the rotation axis to pass through the origin, that is, to reconcile the measurement axis with these three points by vectors. Translation; rotate the three translated points about the translated axis. Angle (using Eigen's axis angle model), calculate the coordinates of the three points after rotation; move the measurement axis back, that is, coordinate the measurement axis and the three points after rotation by vector. Translation; Calculate the new plane equation based on the latest coordinates of the three points, which is the equation after rotation; Update the value of i, making i+1, and repeat the above steps until i = n;

[0091] Step 2: Calculate the point in point set P that is closest to each dividing plane (based on the distance from the point to the plane), and obtain n+1 local dividing points;

[0092] Step 3: Calculate the local pitch based on the formula for local division points and pitch.

[0093] In this embodiment, the flange point P_invert is first located in the point cloud set, and the height difference between the flange point P_invert and the point P_max perpendicular to the first measurement plane is obtained. This height difference is used as the flange height to determine whether the flange height meets the requirements.

[0094] That is, the flange height can be calculated as follows:

[0095] Step 1: Calculate the flanging point based on the given flanging parameters;

[0096] Step 2: Based on the distance from the point to the plane, flip through the distances between the point and the p_max point and the measurement plane respectively. The difference between the two distances is the flipping height.

[0097] This paper presents a simple and efficient propeller testing device, filling a gap in this field. Through long-term research and selection, the optimal device for this solution was selected based on the propeller point cloud.

[0098] This application embodiment acquires propeller point clouds using 3D vision and processes the 3D point clouds using algorithms to accurately measure the propeller's full pitch, local pitch, and flange height. Regarding the selection of the vision sensor, current mainstream 3D vision cameras include binocular cameras, laser line scanners, structured light cameras, and Time-of-Flight (TOF) sensors. Based on the characteristics of the propeller itself, this solution prioritizes structured light cameras or laser line scanners. These two types of cameras offer relatively high accuracy, meeting the accuracy requirements, and have high acquisition efficiency. Structured light cameras, in particular, have extremely high acquisition efficiency and produce relatively clear point clouds with fewer noise points.

[0099] like Figure 5 The diagram shows a schematic representation of the detection device involved in an embodiment of this application. Specifically:

[0100] The detection device may include a processor with one or more processing cores, a memory with one or more computer-readable storage media, a power supply, and input units, etc. Those skilled in the art will understand that the detection device structure shown in the figures does not constitute a limitation on the detection device, and may include more or fewer components than shown, or combine certain components, or have different component arrangements. Wherein:

[0101] The processor is the control center of the detection device. It connects various parts of the detection device via various interfaces and lines. By running or executing software programs and / or modules stored in memory, and by calling data stored in memory, it performs various functions and processes data, thereby providing overall monitoring of the detection device. Optionally, the processor may include one or more processing cores; the processor can be a Central Processing Unit (CPU), or other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor. Preferably, the processor can integrate an application processor and a modem processor, where the application processor mainly handles the operating system, user interface, and applications, and the modem processor mainly handles wireless communication. It is understood that the modem processor may not be integrated into the processor.

[0102] Memory can be used to store software programs and modules. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory. Memory can mainly include a program storage area and a data storage area. The program storage area can store the operating system, at least one application program requiring functionality (such as sound playback, image playback, etc.), etc.; the data storage area can store data created based on the use of the detection device, etc. Furthermore, memory can include high-speed random access memory, and can also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device. Accordingly, memory can also include a memory controller to provide the processor with access to the memory.

[0103] The detection device also includes a power supply for powering the various components. Preferably, the power supply can be connected to the processor logic through a power management system, thereby enabling functions such as charging, discharging, and power consumption management through the power management system. The power supply may also include one or more DC or AC power supplies, recharging systems, power fault detection circuits, power converters or inverters, power status indicators, and other arbitrary components.

[0104] The detection device may also include an input unit, which can be used to receive input digital or character information, and generate keyboard, mouse, joystick, optical or trackball signal inputs related to user settings and function control.

[0105] Although not shown, the detection device may also include a display unit, etc., which will not be described in detail here. Specifically, in this embodiment, the processor in the detection device loads the executable files corresponding to the processes of one or more application programs into the memory according to the following instructions, and the processor runs the application programs stored in the memory to realize various functions, as follows: acquiring the measurement point cloud of the propeller; filtering the measurement point cloud to obtain the target point cloud; processing the target point cloud to obtain the first measurement plane; finding the center point of the pressure cone point cloud; obtaining the measurement axis based on the first measurement plane and the center point; segmenting the target point cloud to obtain the blade point cloud of each blade; analyzing the blade point cloud and the measurement axis to obtain various parameters of the propeller to determine whether the propeller is qualified.

[0106] Further, the measurement point cloud of the propeller is acquired, and the target point cloud is obtained by filtering the measurement point cloud, including:

[0107] A structured light 3D camera is used to detect the propeller and obtain the measurement point cloud of the propeller;

[0108] The measured point cloud is filtered to remove stray point clouds and obtain the target point cloud.

[0109] Furthermore, the target point cloud is processed to obtain the first measurement plane, which includes:

[0110] Step A: Randomly select three non-collinear points from the target point cloud, and use these three points to define a plane;

[0111] Step B: Find inliers from the target point cloud, where points whose distance to the plane is less than a preset distance are considered inliers;

[0112] Step C: Update the three points selected in Step A, redefine a plane, and execute Step B to obtain the interior points of the updated plane;

[0113] In iterative processing step C, after a preset number of iterations, the plane with the most local points is selected as the first measurement plane.

[0114] Furthermore, obtaining the measurement axis based on the first measurement plane and the center point includes:

[0115] Based on the center point of the pressure cone point cloud and the normal vector of the first measurement plane, the equation of the measurement axis line is obtained;

[0116] The equation of the symmetrical measurement axis line is converted into the equation of the intersecting surface measurement axis line to obtain the measurement axis.

[0117] Furthermore, the target point cloud is segmented to obtain the blade point cloud for each blade. Analysis of the blade point cloud and the measurement axis yields various propeller parameters to determine whether the propeller is qualified, including:

[0118] The target point cloud is segmented to obtain the blade point cloud for each blade;

[0119] Calculate the distance value of each blade point cloud from the measurement axis, and add the blade point clouds whose distance values ​​meet the specific distance to the point set P;

[0120] Calculate the point P_max that is farthest from the first measurement plane in the point set P;

[0121] The distance from point P_max to the first measuring plane is taken as the blade height. The full pitch of the propeller is calculated according to the full pitch measurement formula to determine whether the blade height and full pitch meet the requirements.

[0122] Furthermore, the target point cloud is segmented to obtain the blade point cloud for each blade. Analysis of the blade point cloud and the measurement axis yields various propeller parameters. Determining whether the propeller is qualified also includes:

[0123] Calculate the point P_min in the point set P that is closest to the first measurement plane;

[0124] Calculate the second measurement plane formed by point P_max and the measurement axis, and calculate the third measurement plane formed by point P_min and the measurement axis;

[0125] Calculate the target angle between the second and third measurement planes;

[0126] The second measurement plane is divided into n equal division planes based on the local equal division number n and the included angle of the target.

[0127] Calculate the local pitch based on the point set P and each equally divided plane.

[0128] Furthermore, the second measurement plane is divided into n equal divisions based on the local division number n and the included angle of the target, resulting in n equally divided planes, including:

[0129] Based on the local division into n equal parts, the second measuring plane is rotated around the measuring axis by 1 / n times, 2 / n times, ..., (n-1) / n times the included angle of the target, to obtain n equally divided planes.

[0130] Furthermore, calculating the local pitch based on the point set P and each equally divided plane includes:

[0131] Calculate the intersection points of point set P with each equally divided plane, and use these intersection points as input for the local pitch. Calculate the local pitch based on the pitch calculation method and the intersection points to determine whether the local pitch meets the requirements.

[0132] Furthermore, the target point cloud is segmented to obtain the blade point cloud for each blade. Analysis of the blade point cloud and the measurement axis yields various propeller parameters. Determining whether the propeller is qualified also includes:

[0133] Find the flange point P_invert, obtain the height difference between the flange point P_invert and point P_max perpendicular to the first measurement plane, and use this height difference as the flange height to determine whether the flange height meets the requirements.

[0134] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be performed by instructions, or by instructions controlling related hardware. These instructions can be stored in a computer-readable storage medium and loaded and executed by a processor.

[0135] Therefore, embodiments of this application provide a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), a magnetic disk, or an optical disk, etc. A computer program is stored thereon, and the computer program is loaded by a processor to execute the steps in any of the high-precision propeller detection methods provided in embodiments of this application. For example, the computer program loaded by the processor can execute the following steps:

[0136] The measurement point cloud of the propeller is obtained, and the measurement point cloud is filtered to obtain the target point cloud;

[0137] The target point cloud is processed to obtain the first measurement plane, and the center point of the cone-shaped point cloud is found.

[0138] The measurement axis is obtained based on the first measurement plane and the center point;

[0139] The target point cloud is segmented to obtain the blade point cloud of each blade. The blade point cloud and the measurement axis are analyzed to obtain various parameters of the propeller, so as to determine whether the propeller is qualified.

[0140] Further, the measurement point cloud of the propeller is acquired, and the target point cloud is obtained by filtering the measurement point cloud, including:

[0141] A structured light 3D camera is used to detect the propeller and obtain the measurement point cloud of the propeller;

[0142] The measured point cloud is filtered to remove stray point clouds and obtain the target point cloud.

[0143] Furthermore, the target point cloud is processed to obtain the first measurement plane, which includes:

[0144] Step A: Randomly select three non-collinear points from the target point cloud, and use these three points to define a plane;

[0145] Step B: Find inliers from the target point cloud, where points whose distance to the plane is less than a preset distance are considered inliers;

[0146] Step C: Update the three points selected in Step A, redefine a plane, and execute Step B to obtain the interior points of the updated plane;

[0147] In iterative processing step C, after a preset number of iterations, the plane with the most local points is selected as the first measurement plane.

[0148] Furthermore, obtaining the measurement axis based on the first measurement plane and the center point includes:

[0149] Based on the center point of the pressure cone point cloud and the normal vector of the first measurement plane, the equation of the measurement axis line is obtained;

[0150] The equation of the symmetrical measurement axis line is converted into the equation of the intersecting surface measurement axis line to obtain the measurement axis.

[0151] Furthermore, the target point cloud is segmented to obtain the blade point cloud for each blade. Analysis of the blade point cloud and the measurement axis yields various propeller parameters to determine whether the propeller is qualified, including:

[0152] The target point cloud is segmented to obtain the blade point cloud for each blade;

[0153] Calculate the distance value of each blade point cloud from the measurement axis, and add the blade point clouds whose distance values ​​meet the specific distance to the point set P;

[0154] Calculate the point P_max that is farthest from the first measurement plane in the point set P;

[0155] The distance from point P_max to the first measuring plane is taken as the blade height. The full pitch of the propeller is calculated according to the full pitch measurement formula to determine whether the blade height and full pitch meet the requirements.

[0156] Furthermore, the target point cloud is segmented to obtain the blade point cloud for each blade. Analysis of the blade point cloud and the measurement axis yields various propeller parameters. Determining whether the propeller is qualified also includes:

[0157] Calculate the point P_min in the point set P that is closest to the first measurement plane;

[0158] Calculate the second measurement plane formed by point P_max and the measurement axis, and calculate the third measurement plane formed by point P_min and the measurement axis;

[0159] Calculate the target angle between the second and third measurement planes;

[0160] The second measurement plane is divided into n equal division planes based on the local equal division number n and the included angle of the target.

[0161] Calculate the local pitch based on the point set P and each equally divided plane.

[0162] Furthermore, the second measurement plane is divided into n equal divisions based on the local division number n and the included angle of the target, resulting in n equally divided planes, including:

[0163] Based on the local division into n equal parts, the second measuring plane is rotated around the measuring axis by 1 / n times, 2 / n times, ..., (n-1) / n times the included angle of the target, to obtain n equally divided planes.

[0164] Furthermore, calculating the local pitch based on the point set P and each equally divided plane includes:

[0165] Calculate the intersection points of point set P with each equally divided plane, and use these intersection points as input for the local pitch. Calculate the local pitch based on the pitch calculation method and the intersection points to determine whether the local pitch meets the requirements.

[0166] Furthermore, the target point cloud is segmented to obtain the blade point cloud for each blade. Analysis of the blade point cloud and the measurement axis yields various propeller parameters. Determining whether the propeller is qualified also includes:

[0167] Find the flange point P_invert, obtain the height difference between the flange point P_invert and point P_max perpendicular to the first measurement plane, and use this height difference as the flange height to determine whether the flange height meets the requirements.

[0168] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and 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. Therefore, they should not be construed as limitations on this invention.

[0169] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0170] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-precision propeller detection method, characterized in that, Includes the following steps: S1: Obtain the measurement point cloud of the propeller, and filter the measurement point cloud to obtain the target point cloud; S2: Process the target point cloud to obtain the first measurement plane, and find the center point of the cone point cloud; S3: Obtain the measurement axis based on the first measurement plane and the center point; S4: Segment the target point cloud to obtain the blade point cloud of each blade, analyze the blade point cloud and the measurement axis to obtain various parameters of the propeller, and determine whether the propeller is qualified. The process of processing the target point cloud to obtain the first measurement plane includes: Step A: Randomly select three non-collinear points from the target point cloud, and use these three points to define a plane; Step B: Find inliers from the target point cloud, wherein points whose distance to the plane is less than a preset distance are considered inliers; Step C: Update the three points selected in Step A, redefine a plane, and execute Step B to obtain the interior points of the updated plane; In iterative processing step C, after a preset number of iterations, the plane with the most local points is selected as the first measurement plane. The step of obtaining the measurement axis based on the first measurement plane and the center point includes: Based on the center point of the pressure cone point cloud and the normal vector of the first measurement plane, the equation of the measurement axis line is obtained; The equation of the symmetrical measurement axis line is converted into the equation of the intersecting surface measurement axis line to obtain the measurement axis.

2. The high-precision propeller detection method according to claim 1, characterized in that, The process of acquiring the measurement point cloud of the propeller and filtering the measurement point cloud to obtain the target point cloud includes: A structured light 3D camera is used to detect the propeller and obtain the measurement point cloud of the propeller; The measured point cloud is filtered to remove stray point clouds and obtain the target point cloud.

3. A high-precision propeller detection method according to any one of claims 1-2, characterized in that, The process of segmenting the target point cloud to obtain the blade point cloud for each blade, and analyzing the blade point cloud and the measurement axis to obtain various parameters of the propeller to determine whether the propeller is qualified includes: The target point cloud is segmented to obtain the blade point cloud for each blade; Calculate the distance value of each blade point cloud from the measurement axis, and add the blade point clouds whose distance values ​​meet the specific distance to the point set P; Calculate the point P_max that is farthest from the first measurement plane in the point set P; The distance from point P_max to the first measuring plane is taken as the blade height. The full pitch of the propeller is calculated according to the full pitch measurement formula to determine whether the blade height and full pitch meet the requirements.

4. The high-precision propeller detection method according to claim 3, characterized in that, The process of segmenting the target point cloud to obtain the blade point cloud for each blade, and analyzing the blade point cloud and the measurement axis to obtain various parameters of the propeller to determine whether the propeller is qualified, also includes: Calculate the point P_min in the point set P that is closest to the first measurement plane; Calculate the second measurement plane formed by point P_max and the measurement axis, and calculate the third measurement plane formed by point P_min and the measurement axis; Calculate the target angle between the second and third measurement planes; The second measurement plane is divided into n equal division planes based on the local equal division number n and the included angle of the target. Calculate the local pitch based on the point set P and each equally divided plane.

5. The high-precision propeller detection method according to claim 4, characterized in that, The step of dividing the second measurement plane into n equal division planes based on the local equal division number n and the target angle includes: rotating the second measurement plane around the measurement axis by 1 / n times, 2 / n times, ..., (n-1) / n times the target angle based on the local equal division number n, to obtain n equal division planes.

6. The high-precision propeller detection method according to claim 4, characterized in that, The calculation of the local pitch based on the point set P and each equally divided plane includes: Calculate the intersection points of point set P with each equally divided plane, and use these intersection points as input for the local pitch. Calculate the local pitch based on the pitch calculation method and the intersection points to determine whether the local pitch meets the requirements.

7. The high-precision propeller detection method according to claim 1, characterized in that, The process of segmenting the target point cloud to obtain the blade point cloud for each blade, and analyzing the blade point cloud and the measurement axis to obtain various parameters of the propeller to determine whether the propeller is qualified, also includes: Find the flange point P_invert, obtain the height difference between the flange point P_invert and point P_max perpendicular to the first measurement plane, and use this height difference as the flange height to determine whether the flange height meets the requirements.

8. A high-precision propeller detection device, characterized in that, The detection device includes: One or more processors, a memory, and one or more applications; wherein the one or more applications are stored in the memory and configured to be executed by the processor to implement a high-precision propeller detection method according to any one of claims 1 to 7.

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