Full-surface precision detection device and method based on homogeneous medium
By using a six-axis manipulator and ultrasonic water-immersed probe to detect parts in a uniform medium, a three-dimensional model is built and the moving step size is corrected, which solves the problems of low manual detection accuracy and difficult adjustment of moving step size, and achieves efficient and accurate full-surface accuracy Test.
Patent Information
- Application Number
- CN202411340282.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-25
- Publication Date
- 2024-12-27
AI Technical Summary
In the prior art, the manual detection method has low accuracy and poor stability, and it is difficult to set a suitable intermittent motion detection strategy in small or complex surface detection, and it is difficult to correct the movement step length to reduce errors during batch detection.
The full surface accuracy detection device based on a uniform medium is adopted, and the measured object is detected in a uniform liquid medium using a six-axis manipulator and an ultrasonic water-immersion probe. The characteristic parameters are measured by constructing a three-dimensional model image, and the movement step size is corrected according to the deviation of manual detection.
Improve detection accuracy and stability, ensure detection efficiency, and reduce errors, especially in batch detection, the moving step size can be accurately corrected to improve detection accuracy.
Smart Images
Figure CN119197399A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of CNC machine tool parts and assembly accuracy detection, and in particular to a full-surface accuracy detection device and method based on a uniform medium. Background Art
[0002] In the field of CNC machine tool processing and manufacturing, precision testing of parts and component assembly is a very important link. From the initial processing and assembly of parts to the final finished product, it will go through multiple inspection processes of various shapes and position matching accuracy.
[0003] The current detection method mainly measures the shape and position accuracy of the measured surface by collecting the position accuracy of the sampling points on the measured surface or the position accuracy of the sampling lines on the measured surface. However, the accuracy of the detection accuracy is greatly affected by the actual situation of the sampling points and the representativeness of the sampling data. In addition, because the surfaces of some parts that need to be detected are small or the positions are difficult to detect, the selected detection sampling points are less representative. In addition, the detection accuracy error of the inspection tool itself makes the detection results have a certain error with the actual accuracy or are inconsistent with the accuracy requirements. In the existing detection method, the inspection tools used include micrometers, vernier calipers and feeler gauges, and are combined with visual measurement. This method not only has low detection accuracy and poor stability, but also has a slow detection speed, which cannot meet the current increasing detection efficiency and accuracy requirements. To this end, we provide a full-surface accuracy detection device and method based on a uniform medium. Summary of the invention
[0004] The object of the present invention is to provide a full-surface precision detection device and method based on a uniform medium.
[0005] The technical problems solved by the present invention are:
[0006] (1) The manual detection method in the prior art has low accuracy and poor stability;
[0007] (2) How to set the parameters of the intermittent mobile detection strategy when the detected surface includes both flat and curved surfaces;
[0008] (3) How to correct the moving step size based on the relative deviation from manual inspection when batch inspecting the same batch of parts.
[0009] The present invention can be implemented by the following technical scheme: a full-surface precision detection device based on uniform medium, comprising a detection workbench, a container loaded with uniform liquid medium is arranged on the top of the detection workbench, and a detected object is immersed and fixed in the uniform liquid medium;
[0010] A six-axis manipulator is arranged above the container on the detection workbench. A signal generating device integrated with a data acquisition module is fixed at the movable end of the six-axis manipulator. The echo of the ultrasonic signal generated by the signal generating device is received by the data acquisition module and converted into an electrical signal and sent to the data analysis module for modeling and analysis, and the results are output.
[0011] A further technical improvement of the present invention is that the signal generating device is configured as an ultrasonic immersion probe, which is immersed in a uniform liquid medium during detection.
[0012] A full-surface precision detection method based on a uniform medium specifically comprises the following steps:
[0013] Step 1: Load the object to be tested under the surface of a uniform liquid medium, with the top of the object being tested as the surface to be tested;
[0014] Step 2: Define the inspection area according to the accuracy inspection requirements;
[0015] Step 3: setting an intermittent movement detection strategy of the ultrasonic probe and implementing the detection;
[0016] Step 4: construct a three-dimensional model image of the detected surface according to the detection data;
[0017] Step 5: Measure the parameters of relevant features on the 3D model image, calculate the difference between the parameters and the design parameters, and display the results;
[0018] Step 6: When the objects to be tested are large quantities of parts from the same batch, ultrasonic probe detection is compared with manual detection to obtain the relative deviation rate of the two regarding accuracy, and the mobile detection strategy is corrected based on the comparison result of the relative deviation rate and the set threshold.
[0019] A further technical improvement of the present invention is that when demarcating the detection area in step one, the detection range is set at the edge of the feature to be detected and equidistantly extends a certain distance, and the range is the detection area.
[0020] A further technical improvement of the present invention is that the mobile detection strategy in step three includes the selection of detection points, the determination of the trajectory of intermittent movement and the setting of the moving step length.
[0021] A further technical improvement of the present invention is that the detection point selection is based on two principles: full coverage of the detection area and relative reduction of the overlapping area. The radius of the circular detection circle of the ultrasonic probe of a certain model is set to R, so that adjacent circular detection circles are circumscribed to each other, and multiple detection points are set at the center of the gap between two rows of circular detection circles;
[0022] The method of determining the trajectory of the intermittent movement between the detection points is: the detection movement is performed row by row according to the S-shaped trajectory, and each time a step is moved, it stays at the corresponding point for a set time and then moves to the next monitoring point.
[0023] A further technical improvement of the present invention is that the moving step length is set to 2R-d i-1 *tanθ i , where θ i is the following angle of the current position, d i-1 is the distance between the ultrasonic probe and the detected surface at the previous detection position of the position, and i is the number of the circular detection circle;
[0024] During the test, the distance between the tested surface and the ultrasonic probe And the distance is bound to the coordinates of the ultrasound probe in the plane.
[0025] A further technical improvement of the present invention is that when constructing a three-dimensional model, the coordinates of the overlapping area of the circular detection circle are corrected by the mean method, and the data is fitted by polynomial interpolation or spline interpolation between the moving steps between two adjacent detection points, and the fitted image model is smoothed.
[0026] A further technical improvement of the present invention is that the specific process of comparing the accuracy and correcting the parameters of the ultrasonic probe detection and manual detection in step 6 includes:
[0027] Calculate the absolute deviation rates p1 and p2 of ultrasonic probe detection and manual detection in the same batch respectively. The calculation method is: Among them, A j represents the detection value of the jth part in a certain data, and A is the design parameter corresponding to the part;
[0028] Calculate the relative deviation rate of the ultrasonic probe relative to manual detection
[0029] When the relative deviation rate is less than the set threshold, it indicates that the detection result of the ultrasonic probe is reliable; when the relative deviation rate is not less than the set threshold, the moving step length is reduced.
[0030] A further technical improvement of the present invention is that the measure of moving the step length includes reducing the distance between the ultrasonic probe and the detected surface or reducing the radius of the circular detection circle by selecting the ultrasonic probe.
[0031] Compared with the prior art, the present invention has the following beneficial effects:
[0032] The present invention detects the top surface of the part to be inspected by an ultrasonic probe, and uses data analysis software to perform three-dimensional modeling on the surface of the part to be inspected, thereby completely restoring the shape and position characteristics of the entire surface to be inspected, and by calculating the dimensional tolerance data of each shape and position feature in the three-dimensional model, it is determined whether the relevant features of the surface to be inspected of the part are processed qualified, thereby replacing the traditional manual measurement mode one by one, with high stability and guaranteed efficiency;
[0033] On the other hand, when inspecting the surface to be inspected, the existence of the curved surface is comprehensively considered, and the moving step length is compensated according to the tracking angle of the ultrasonic probe to ensure that no blank areas are missed. When inspecting large quantities of parts from the same batch, the moving step length is corrected to reduce detection errors and improve detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.
[0035] Figure 1 It is a schematic diagram of the connection structure of the precision detection device of the present invention;
[0036] Figure 2 It is a schematic diagram of the detection method of the present invention;
[0037] Figure 3 It is a schematic diagram of the detection point distribution state of the present invention.
[0038] In the figure: 1. signal generating device; 2. data acquisition module; 3. data analysis module; 4. object to be measured; 5. detection workbench. DETAILED DESCRIPTION
[0039] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.
[0040] See also Figure 1 As shown, a full-surface precision detection device based on uniform medium includes a detection workbench 5, which is used to place and load the object to be tested 4. The object to be tested 4 can be a part to be tested of various shapes and a certain size, or a mounting part on an assembly with relative position accuracy. In order to improve the detection accuracy, a standard container loaded with uniform liquid medium is provided on the detection workbench 5, and the object to be tested 4 is immersed in the uniform liquid medium;
[0041] Specifically, the uniform liquid medium preferably uses a single flowable liquid medium with stable chemical properties (such as water, alcohol or oil). Under the condition that the environmental conditions remain constant, the stable and uniform medium conduction characteristics can ensure the stability of the conduction characteristics, so as to further improve the detection accuracy;
[0042] A signal generating device 1 which can be installed on the movable end of the six-axis manipulator is arranged directly above the detection workbench 5. The signal generating device 1 is integrated with a data acquisition module 2. The data acquisition module 2 receives all acoustic wave feedback signals and converts them into electrical signals. The electrical signals are then transmitted to the data analysis module 3 in the computer through a transmission interface for data modeling and accuracy detection comparison, and the detection judgment results are output.
[0043] Specifically, the signal generating device may adopt an ultrasonic water immersion probe.
[0044] like Figure 2 As shown, taking the object 4 as a part to be tested as an example, the method for testing using the above-mentioned accuracy testing device specifically includes the following steps:
[0045] Step 1: Install and load the object 4
[0046] The object to be tested 4 is fixed in a standard container and immersed in a uniform liquid medium, with the surface to be tested facing upward toward the signal generating device 1;
[0047] Step 2: Define the detection area
[0048] The inspection area is delineated according to the inspection requirements, which include the inherent accuracy of a certain feature or the relative accuracy between different features. For example, when it is necessary to inspect the inherent features such as the length and width of the slot on the part, the rectangular area at a certain distance from the edge of the slot is set as the inspection range; when it is necessary to inspect the aperture accuracy of the circular hole on the part, a certain distance from the outer edge of the circumscribed rectangle of the circular hole is used as the inspection range; when it is necessary to inspect the relative positioning accuracy between two different hole positions, the inspection range around the two hole positions is inspected separately, and the movement coordinates of the robot in the two inspection ranges are recorded; the entire upper surface can also be used as the inspection range for comprehensive imaging.
[0049] Step 3: Set the ultrasound probe movement step length
[0050] When performing ultrasonic testing, since the object 4 is fixed, the ultrasonic probe moves once, reflects and receives ultrasonic waves for testing, and the distance the ultrasonic probe moves each time is the moving step length. At the same time, the area range of the ultrasonic probe for testing each time is limited, and is a circular area with a certain radius by default.
[0051] If a complete inspection of the entire inspection surface of the object 4 is required, the ultrasonic probe needs to be moved multiple times until the entire inspection surface is covered;
[0052] In order to avoid the coordinate calculation being too complicated and to reduce the overlap of each detection range of the ultrasonic probe to a certain extent, the moving step length in the X-axis direction and the Y-axis direction is set to 2R, where R is the radius of a single circular detection circle corresponding to a certain type of ultrasonic probe. At this time, the ultrasonic probe detection point distribution is as follows: Figure 3 As shown;
[0053] The above-mentioned moving step length setting is based on the fact that the detected surface is a plane. When there is a curved surface with a certain curvature in the detected surface, the manipulator drives the ultrasonic probe to deflect the following angle, and the moving step length at this time is related to the following angle θ;
[0054] When the ultrasonic probe is deflected in the opposite direction of movement, the two adjacent circular detection circles will overlap in area. Although this will increase the number of movements, it will not cause area omissions. However, when the ultrasonic probe is deflected in the same direction of movement, it will cause area omissions. In this case, the moving step size is set to 2R-d. i-1 *tanθ i , where θ i is the following angle of the current position, d i-1 is the distance between the ultrasonic probe and the detected surface measured at the previous detection position of this position, and i is the number of the circular detection circle; it should be noted that d is used here. i-1 Approximately represents d i It will not cause the data error to become larger, because the surface changes continuously. From the differential point of view, when moving a very short distance on the surface, the height positions of the two points can be considered to be consistent.
[0055] Step 4: Data Collection
[0056] The ultrasonic probe is moved row by row along an S-shaped trajectory. First, it is intermittently moved according to the set moving step length. After each step length, it briefly stops at the corresponding point. The dwell time can be set, generally 0.2 to 0.5 seconds. Then it moves to the next detection point until the entire trajectory of the detected surface is completed. Then, the blank area (i.e., the undetected area) formed between each two adjacent rows is supplemented with detection. The detection method and moving step length are the same as above.
[0057] During the intermittent dwelling process, the ultrasonic probe emits ultrasonic pulses. By recording the emission time of the ultrasonic pulse and the reception time of the ultrasonic echo, the time difference Δt is obtained. Then, according to the transmission speed v of the ultrasonic pulse in the uniform liquid medium, the distance between the detected surface and the ultrasonic probe is obtained. And the distance is bound to the coordinates of the ultrasound probe in the plane;
[0058] Since some ultrasonic waves will form multiple echoes between the ultrasonic probe and the surface being tested, only the valid data of the first echo is taken, that is, the reception time of the first ultrasonic echo, and the other reception times are invalid data;
[0059] Step 5: Model construction
[0060] The data analysis module 3 draws virtual detection points and virtual circular detection circles in the newly created three-dimensional space coordinate system according to the horizontal coordinates of the ultrasonic probe at each detection position and the distance d between the detected surface and the ultrasonic probe;
[0061] In the overlapping area of the circular detection circle, the mean method is used to correct the coordinates of the area, and the polynomial interpolation method or spline interpolation method is used to fit the data between the moving steps of two adjacent detection points, and the fitted image model is smoothed.
[0062] Step 6: Output of accuracy test results
[0063] According to the model constructed in the above steps, the relevant parameters of the corresponding features are measured and compared with the design parameters, so that the test results and accuracy deviation values can be calculated and quickly displayed on the computer.
[0064] Step 7: Accuracy comparison and parameter correction
[0065] When testing a large number of parts in the same batch, a number of parts are randomly selected for pre-testing using an ultrasonic probe, and then the data are compared through manual testing. The absolute deviation rate of the two sets of data relative to the design parameters is calculated respectively. The calculation method is: The absolute deviation rate p1 of the ultrasonic probe pre-detection and the absolute deviation rate p2 of the manual detection are obtained, where A j represents the detection value of the jth part in a certain data, and A is the design parameter corresponding to the part;
[0066] Calculate the relative deviation rate of the ultrasonic probe relative to manual detection When the relative deviation rate is less than the set threshold, it means that the detection result of the ultrasonic probe is reliable; when the relative deviation rate is not less than the set threshold, the moving step length is reduced. Measures to reduce the moving step length include reducing the distance between the ultrasonic probe and the surface to be detected or reducing the radius of the circular detection circle by selecting the ultrasonic probe.
[0067] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.
Claims
1. A full-surface precision detection device based on a uniform medium, characterized in that: It comprises a detection workbench (5), the top of which is provided with a container loaded with a uniform liquid medium, and a detected object (4) is immersed and fixed in the uniform liquid medium; A six-axis manipulator is arranged above the container on the detection workbench (5), and a signal generating device (1) integrated with a data acquisition module (2) is fixed to the movable end of the six-axis manipulator. The echo of the ultrasonic signal generated by the signal generating device (1) is received by the data acquisition module (2) and converted into an electrical signal, which is sent to the data analysis module (3) for modeling analysis and output of the result.
2. The full-surface precision detection device based on a uniform medium according to claim 1, characterized in that: The signal generating device is configured as an ultrasonic immersion probe, which is immersed in a uniform liquid medium during detection.
3. A precision detection method based on the device of claim 2, characterized in that: The specific steps include: Step 1: Load the object to be tested (4) below the surface of a uniform liquid medium, with the top of the object to be tested being the surface to be tested; Step 2: Define the inspection area according to the accuracy inspection requirements; Step 3: setting an intermittent movement detection strategy of the ultrasonic probe and implementing the detection; Step 4: construct a three-dimensional model image of the detected surface according to the detection data; Step 5: Measure the parameters of relevant features on the 3D model image, calculate the difference between the parameters and the design parameters, and display the results; Step 6: When the object to be tested (4) is a large number of parts from the same batch, the ultrasonic probe detection is compared with the manual detection to obtain the relative deviation rate of the two regarding accuracy, and the mobile detection strategy is corrected based on the comparison result of the relative deviation rate and the set threshold.
4. The full surface accuracy detection method based on a uniform medium according to claim 3 is characterized in that: In step 1, when demarcating the detection area, the detection range is set at the edge of the feature to be detected and equidistantly extends a certain distance, and the range is the detection area.
5. The full surface accuracy detection method based on a uniform medium according to claim 3 is characterized in that: The mobile detection strategy in step three includes the selection of detection points, the determination of the trajectory of intermittent movement, and the setting of the moving step length.
6. The full surface accuracy detection method based on a uniform medium according to claim 5, characterized in that: The detection points are selected based on two principles: full coverage of the detection area and relative reduction of the overlapping area. The radius of the circular detection circle of the ultrasonic probe of a certain model is set to R, so that adjacent circular detection circles are circumscribed to each other, and multiple detection points are set at the center of the gap between two rows of circular detection circles; The method of determining the trajectory of the intermittent movement between the detection points is: the detection movement is performed row by row according to the S-shaped trajectory, and each time a step is moved, it stays at the corresponding point for a set time and then moves to the next monitoring point.
7. A full-surface precision detection method based on a uniform medium according to claim 6, characterized in that: The moving step is set to 2R-d i-1 *tanθ i , where θ i is the following angle of the current position, d i-1 is the distance between the ultrasonic probe and the detected surface at the previous detection position of the position, and i is the number of the circular detection circle; During the test, the distance between the tested surface and the ultrasonic probe And the distance is bound to the coordinates of the ultrasound probe in the plane.
8. The full surface accuracy detection method based on a uniform medium according to claim 6, characterized in that: When constructing a three-dimensional model, the coordinates of the overlapping area of the circular detection circle are corrected using the mean method, and the data is fitted using polynomial interpolation or spline interpolation between the moving steps between two adjacent detection points, and the fitted image model is smoothed.
9. The full surface accuracy detection method based on a uniform medium according to claim 6, characterized in that: The specific process of comparing the accuracy and correcting the parameters of the ultrasonic probe detection and manual detection in step 6 includes: Calculate the absolute deviation rates p1 and p2 of ultrasonic probe detection and manual detection in the same batch respectively. The calculation method is: Among them, A j represents the detection value of the jth part in a certain data, and A is the design parameter corresponding to the part; Calculate the relative deviation rate of the ultrasonic probe relative to manual detection When the relative deviation rate is less than the set threshold, it indicates that the detection result of the ultrasonic probe is reliable; when the relative deviation rate is not less than the set threshold, the moving step length is reduced.
10. A full surface accuracy detection method based on a uniform medium according to claim 9, characterized in that: The measures for increasing the moving step length include reducing the distance between the ultrasonic probe and the detected surface or reducing the radius of the circular detection circle by selecting the ultrasonic probe.