Automobile shock absorber assembly quality inspection device, quality inspection method and system

Abstract

The present application relates to the field of quality inspection technology, and specifically to an automobile shock absorber assembly quality inspection device, quality inspection method, and system. The method comprises: obtaining the displacement distance, damping force, and temperature of a sampling point; presetting a cycle, and obtaining the possibility of temperature influence at the sampling point within the cycle based on the differences between different cycles and the differences between sampling points between cycles; selecting several historical cycles, and constructing a temperature-related coordinate system based on the temperature differences and temperature influence possibilities of the sampling points between cycles and historical cycles; clustering and numbering the coordinate system, and forming a temperature influence coordinate system with the sampling points of the current cycle and each historical cycle in numerical order; determining outliers based on the temperature influence coordinate system, and obtaining the probability of the shock absorber being affected by assembly problems based on the number of outliers, the variance of their serial numbers, and the distance; and performing quality inspection on the shock absorber based on this. The present application improves the accuracy of actual quality inspection of shock absorbers.

Description

Technical Field

[0001] The present application relates to the technical field of quality inspection, and in particular to an automobile shock absorber assembly quality inspection device, quality inspection method and system. Background Art

[0002] The shock absorber is installed in parallel with the elastic element in the suspension system of the car. When the car frame (or body) vibrates on the suspension, the oil in the shock absorber flows from one cavity through the damping hole to another inner cavity. At this time, the friction between the hole wall and the oil and the friction within the liquid molecules form a damping force on the vibration, attenuating the vibration of the car body and converting the vibration energy of the car into heat energy and dissipating it. The magnitude of the shock absorber damping force increases and decreases with the relative speed of the frame and the axle, thereby improving the driving smoothness and handling stability of the car.

[0003] During the quality inspection of shock absorbers, air may enter the shock absorber due to improper assembly, forming bubbles, affecting the fluidity of the oil and the stability of the damping force, and also making the indicator diagram uneven. At this time, the changes in the indicator diagram caused by assembly and the changes in the indicator diagram caused by temperature have the same data characteristics, which can easily lead to misjudgment, thereby reducing the accuracy of the actual quality inspection of the shock absorber. Summary of the Invention

[0004] In order to solve the technical problem of low quality inspection accuracy, this application provides an automobile shock absorber assembly quality inspection device, quality inspection method and system. The technical solutions adopted are as follows:

[0005] In a first aspect, the present application proposes a method for quality inspection of automobile shock absorber assembly, the method comprising the following steps:

[0006] The displacement distance, damping force and temperature of each sampling point are obtained based on different sensors, and the dynamometer diagram is constructed according to the displacement distance and damping force of the sampling point;

[0007] The time taken by the shock absorber piston to move from the top dead center to the bottom dead center and then back to the top dead center is recorded as a cycle; all sampling points in each cycle are sorted in chronological order, the sequence number of each sampling point is obtained, and the cycle difference between the two cycles is calculated based on the length of the two cycles; the current cycle to be tested is recorded as the current cycle, and the previous cycle is recorded as the historical cycle; the temperature impact trend of the sampling point is obtained based on the difference between the sampling points of the current cycle and the historical cycle; the temperature impact possibility of the sampling point of the current cycle is obtained based on the cycle difference between the current cycle and the historical cycle and the temperature impact trend of the sampling point of the current cycle;

[0008] A preset number of historical periods before the current period are selected; the temperature difference between the sampling points in the current period and each historical period and the possibility of temperature influence are used as the horizontal and vertical coordinates to construct a temperature-related coordinate system for the current period and each historical period; for each temperature-related coordinate system, the cluster center is determined based on the minimum distance between all data points; the data points are numbered from largest to smallest according to their distance from the cluster center, and all data points with the same number in the temperature-related coordinate system are added to the new coordinate system in order of the number to form several temperature-affected coordinate systems; the outliers are determined based on the distance between the data points in the temperature-affected coordinate system, and the influence value is determined by the ratio of the number of outliers to the number of all sampling points in the historical period; the probability that the shock absorber is affected by the assembly problem is obtained based on the variance of the ordinal value of the outliers in the current period, the influence value, and the distance between the outliers and the cluster center;

[0009] Determine whether the shock absorber has any abnormalities based on the probability that the shock absorber is affected by assembly problems, and perform quality inspection on the shock absorber.

[0010] In the above scheme, by analyzing the distance difference at the same sampling number in the dynamometer diagram corresponding to different periods, the difference in the change of the dynamometer diagram at the same number in the two periods is inferred, thereby judging the possibility of temperature influence, and reconstructing a new coordinate system based on the possibility and the temperature difference, and comparing the aggregation of data points between different periods. Based on this method, the influence of nonlinear temperature change on the actual dynamometer diagram change is eliminated, and the outliers are screened based on the coordinate system after eliminating the temperature influence, and then the section of the original dynamometer diagram affected by the assembly problem is inferred; this operation avoids the misjudgment caused by the same data features between the dynamometer diagram changes caused by assembly and the dynamometer diagram changes caused by temperature, thereby improving the accuracy of the actual quality inspection of the shock absorber.

[0011] In one embodiment, the cycle difference is calculated by calculating the absolute value of the difference between the cycle lengths of two cycles.

[0012] In one embodiment, the method for obtaining the temperature influence trend of the sampling point based on the difference between the sampling points of the current cycle and the historical cycles is:

[0013] If the number of sampling points in the current cycle is less than or equal to the number of sampling points in the historical cycle, the difference between each sampling point in the current cycle and the sampling point with the same serial number in the historical cycle is calculated to obtain the temperature influence trend of the sampling point in the current cycle;

[0014] If the number of sampling points in the current cycle is greater than the number of sampling points in the historical cycle, the difference between the last sampling point in the historical cycle and the remaining uncalculated sampling points in the current cycle is used to obtain the temperature impact trend of the remaining sampling points in the current cycle;

[0015] The temperature impact trend is calculated by calculating the Euclidean distance between two sampling points.

[0016] In one embodiment, the method for obtaining the temperature impact possibility of the current cycle sampling point based on the period difference between the current cycle and the historical cycle and the temperature impact trend of the current cycle sampling point is:

[0017] The cycle difference between the current cycle and the historical cycle is recorded as the temperature impact weight of the current cycle;

[0018] The possibility of temperature impact is positively correlated with the temperature impact weight of the current period and the temperature impact trend of the sampling point in the current period.

[0019] In one embodiment, the method for constructing a temperature-related coordinate system for the current period and each historical period using the temperature difference between the sampling points in the current period and each historical period and the temperature influence possibility as the horizontal and vertical coordinates is as follows:

[0020] Calculate the temperature difference between each sampling point in the current cycle and the sampling points in the historical cycle as the temperature difference of each sampling point in the current cycle;

[0021] If the number of sampling points in the current cycle is less than or equal to that in the historical cycle, the temperature difference between each sampling point in the current cycle and the sampling point with the same sequence number in the historical cycle is calculated;

[0022] If the number of sampling points in the current cycle is greater than that in the historical cycle, then for the sampling point with a sequence number greater than the maximum sequence number of the sampling points in the historical cycle, calculate the temperature difference between it and the sampling point with the maximum sequence number in the historical cycle;

[0023] The temperature difference was calculated as the absolute value of the difference between the temperatures at two sampling points;

[0024] Let the temperature difference of the sampling points be the horizontal axis and the temperature influence possibility of the sampling points be the vertical axis to construct a coordinate system. For the current period and any historical period, all sampling points corresponding to the current period are added to the coordinate system as the temperature-related coordinate system of the current period and any historical period.

[0025] In one embodiment, the method of adding the data points with the same labels in all temperature-related coordinate systems to a new coordinate system in the order of the labels to form a plurality of temperature-affected coordinate systems is as follows:

[0026] Using the temperature difference as the horizontal axis and the temperature influence possibility as the vertical axis, an empty coordinate system is reconstructed and recorded as the temperature influence coordinate system; the data points of all temperature-related coordinate systems are added to the temperature influence coordinate system according to the number of the data points. Each time a data point is added, one data point is added to each temperature-related coordinate system; when the data points with the same serial number are added, it is considered an iteration, and a new temperature influence coordinate system is obtained after each iteration is completed, until all the data points of the temperature-related coordinate systems are added to the temperature influence coordinate system.

[0027] In one embodiment, the method of determining the outlier points based on the distance between data points in the temperature impact coordinate system and determining the impact value based on the ratio of the number of outlier points to the number of all sampling points in the historical period is:

[0028] Calculate the Euclidean distances between all data points in each temperature-affected coordinate system, and take the mean of all Euclidean distances as the mean distance of the temperature-affected coordinate system; record all data points in the temperature-affected coordinate system corresponding to the minimum value of the mean distance as outliers;

[0029] The expression of the impact value is:

[0030] , represents the number of outliers, represents the number of historical periods, represents the mean number of sampling points in all historical periods, Indicates the impact value.

[0031] In one embodiment, the method for obtaining the probability that the shock absorber is affected by the assembly problem based on the variance of the sequence number value of the outlier point in the current cycle, the influence value, and the distance between the outlier point and the cluster center is:

[0032] , represents the variance of the ordinal values ​​of all outliers, Indicates the impact value, represents the distance parameter of the kth outlier point, represents the number of outliers, Indicates the probability that the shock absorber is affected by an assembly problem.

[0033] In a second aspect, the present application further provides an automobile shock absorber assembly quality inspection system, the system comprising:

[0034] A data acquisition module is used to obtain the displacement distance, damping force and temperature of each sampling point based on different sensors, and to construct a dynamometer diagram based on the displacement distance and damping force of the sampling point;

[0035] The temperature impact possibility acquisition module is used to record the time taken by the shock absorber piston from the top dead center to the bottom dead center and then back to the top dead center as a cycle; sort all sampling points in each cycle in chronological order, obtain the sequence number of each sampling point, and calculate the cycle difference between the two cycles based on the lengths of the two cycles; record the current cycle to be detected as the current cycle, and the previous cycle as the historical cycle; obtain the temperature impact trend of the sampling point based on the difference between the sampling points of the current cycle and the historical cycle; and obtain the temperature impact possibility of the sampling point of the current cycle based on the cycle difference between the current cycle and the historical cycle and the temperature impact trend of the sampling point of the current cycle;

[0036] The module for obtaining the probability that the shock absorber is affected by assembly problems is used to select a preset number of historical periods before the current period; use the temperature difference between the sampling points in the current period and each historical period and the possibility of temperature influence as the horizontal and vertical coordinates to construct a temperature-related coordinate system for the current period and each historical period; for each temperature-related coordinate system, determine the cluster center based on the minimum distance between all data points; label the data points from large to small according to their distance from the cluster center, and add all data points with the same label in the temperature-related coordinate system to the new coordinate system in the order of the label to form several temperature-affected coordinate systems; determine the outliers based on the distance between the data points in the temperature-affected coordinate system, and determine the influence value based on the ratio of the number of outliers to the number of all sampling points in the historical period; and obtain the probability that the shock absorber is affected by the assembly problem based on the variance of the serial number value of the outliers in the current period, the influence value, and the distance between the outliers and the cluster center.

[0037] The quality inspection module is used to determine whether the shock absorber has any abnormality based on the probability that the shock absorber is affected by the assembly problem, and to perform quality inspection on the shock absorber.

[0038] In a third aspect, an embodiment of the present application further provides an automobile shock absorber assembly quality inspection device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein when the processor executes the computer program, the steps of any one of the above-mentioned automobile shock absorber assembly quality inspection methods are implemented.

[0039] The beneficial effects of this application are:

[0040] The present application analyzes the distance difference at the same sampling number in the dynamometer diagram corresponding to different periods, and then infers the difference in the change of the dynamometer diagram at the same number in the two periods, thereby judging the possibility of temperature influence, and reconstructs a new coordinate system based on the possibility and the temperature difference, and compares the aggregation of data points between different periods. Based on this method, the influence of nonlinear temperature change on the actual dynamometer diagram change is eliminated, and the outliers are screened based on the coordinate system after eliminating the temperature influence, and then infer the section of the original dynamometer diagram affected by assembly problems; this operation avoids the misjudgment caused by the same data features between the dynamometer diagram changes caused by assembly and the dynamometer diagram changes caused by temperature, and improves the accuracy of the actual quality inspection of the shock absorber. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0042] Figure 1 An automobile shock absorber assembly quality inspection device, quality inspection method, and system flow chart provided in one embodiment of the present application;

[0043] Figure 2 This is a schematic diagram of a quality inspection device for automobile shock absorber assembly. DETAILED DESCRIPTION

[0044] To further illustrate the technical means and effectiveness of this application to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail the specific implementation, structure, features, and effectiveness of an automotive shock absorber assembly quality inspection device, quality inspection method, and system proposed in this application. In the following description, references to different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0045] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0046] An automobile shock absorber assembly quality inspection device, quality inspection method and system embodiment:

[0047] The following describes in detail a specific solution of an automobile shock absorber assembly quality inspection device, quality inspection method and system provided by the present application with reference to the accompanying drawings.

[0048] See also Figure 1 , which shows an automobile shock absorber assembly quality inspection device, quality inspection method and system flow chart provided by one embodiment of the present application. The method includes the following steps:

[0049] Step S001: Obtain the displacement distance, damping force and temperature of the sampling point and construct a dynamometer diagram.

[0050] A counting sensor counts each piston movement, each count being a sampling point. A displacement sensor measures the displacement distance of each sampling point as the shock absorber piston moves, and a high-speed central processing unit detects the damping force at each sampling point in the shock absorber. The displacement distances of all sampling points and the corresponding damping force are plotted on the shock absorber's indicator diagram.

[0051] The shock absorber will generate friction during operation, causing the temperature of the entire shock absorber to rise. By detecting the shock absorber temperature, it can be evaluated whether there is any abnormal working state during operation. At the same time, its thermal fatigue under long-term operation can be evaluated, and then the shock absorber can be subjected to durability testing. The temperature of each sampling point is obtained through the temperature sensor.

[0052] The displacement and counting sensors collect and count the piston displacements within the shock absorber, and the high-speed central processing unit detects the damping force. The shock absorber's dynamometer diagram is plotted by combining all the piston displacements counted and the corresponding damping force. The abscissa of the diagram represents the displacement distance at each sampling point, and the ordinate represents the damping force corresponding to each sampling point.

[0053] At this point, the shock absorber's dynamometer diagram and the temperature at each sampling point are obtained.

[0054] Step S002 : sorting the sampling points of each cycle, and obtaining the temperature impact possibility of each cycle according to the difference between the two cycles and the difference between the sampling points of the two cycles.

[0055] Temperature fluctuations affect the viscosity of the oil inside the shock absorber, which in turn affects the damping force. When the temperature rises, the oil viscosity decreases, reducing the damping force; when the temperature drops, the oil viscosity increases, increasing the damping force. This change is reflected on the dynamometer diagram, manifesting as changes in the shape and height of the damping force curve. Temperature fluctuations can also alter the shock absorber's damping characteristics, resulting in a less smooth curve on the dynamometer diagram and the possibility of nonlinear segments or sudden changes. During the shock absorber quality inspection process, improper assembly can cause air to enter the shock absorber, creating bubbles that affect the fluidity of the oil and the stability of the damping force, also causing the dynamometer diagram to become less smooth. The changes in the dynamometer diagram caused by assembly and temperature share common data characteristics, making it easy to misjudge, thereby reducing the accuracy of the shock absorber's actual quality inspection.

[0056] Therefore, it is necessary to analyze the abnormal curve of the dynamometer diagram to distinguish whether the change in the dynamometer diagram is caused by assembly or temperature.

[0057] The shock absorber's piston moves from top dead center to bottom dead center and back to top dead center, a process known as a cycle. The damping force varies over time, so different cycles on the dynamometer diagram will show some differences. However, the piston travels the same distance, and, without external influences, the number of sampling points corresponding to each cycle remains the same.

[0058] All sampling points are numbered in chronological order, and each sampling point has a serial number. When there is an assembly problem with the shock absorber that causes the indicator diagram to be uneven, the impact on each cycle is the same, that is, the displacement distance of the sampling point in each cycle should change slightly, while the cycle length itself remains unchanged; however, when affected by temperature, the displacement distance of the sampling point changes significantly, and the piston moves faster, that is, the time period for the piston to complete a cycle of movement becomes shorter, and there is a certain difference in the cycle length.

[0059] For any two cycles, the period difference between the two cycles is calculated. The larger the period difference, the greater the period variation between the two cycles, and the higher the possibility of temperature influence. In this embodiment, the period difference between the two cycles is calculated by calculating the absolute value of the difference between the period lengths of the two cycles.

[0060] Select a historical period from the historical data; record the period to be tested as the current period, and calculate the temperature impact trend of the sampling points based on the difference between the sampling points with the same sequence number in the current period and the historical period. If the number of sampling points in the current period is greater than that in the historical period, calculate the temperature impact trend of the remaining sampling points in the current period based on the difference between the last sampling point in the historical period and the remaining uncalculated sampling points in the current period. In other words, each sampling point in the current period has a corresponding sampling point in the historical period.

[0061] For example, if the sampling points in the current cycle are numbered {1, 2, 3, 4, 5} and the sampling points in the historical cycle are numbered {1, 2, 3, 4}, then when calculating the sampling points with the same number, the temperature impact trend of all sampling points in the current cycle is calculated by analyzing the differences between the sampling points {1, 1}, {2, 2}, {3, 3}, {4, 4}, and {5, 4}.

[0062] The horizontal coordinate of each sampling point is its displacement distance, and the vertical coordinate is its damping force, that is, each sampling point is a two-dimensional point; the calculation method of temperature influence trend is to calculate the Euclidean distance between the sampling point of the current period and the sampling point corresponding to the historical period.

[0063] The temperature impact probability of the sampling point in the current period is obtained according to the temperature impact weight of the current period and the temperature impact trend of the sampling point in the current period.

[0064] The possibility of temperature impact is positively correlated with the temperature impact weight of the current period and the temperature impact trend of the sampling point in the current period.

[0065] It should be noted that positive correlation means that when one variable increases, the other variable also increases, and the two variables change in the same direction. When one variable changes from large to small or from small to large, the other variable also changes from large to small or from small to large; the specific relationship is determined by actual application and this application does not impose any special restrictions.

[0066] Preferably, in this embodiment, the period difference between the current period and the historical period is calculated, and the period difference is used as the temperature impact weight of the current period; the product of the temperature impact weight of the current period and the temperature impact trend of each sampling point in the current period is used as the temperature impact possibility of each sampling point in the current period.

[0067] At this point, the temperature impact possibility of each sampling point in the current cycle is obtained.

[0068] Step S003: Construct a temperature-related coordinate system based on the temperature difference and temperature influence probability of the sampling points in the current cycle and the historical cycles; cluster and sort the data points therein, and form a temperature influence coordinate system based on the sorted order of all data points with the same sequence number in the temperature-related coordinate system; determine the outliers based on the temperature influence coordinate system, and obtain the probability that the shock absorber is affected by the assembly problem based on the proportion of the outliers, the variance of the sequence number of the outliers, and the distance of the outliers.

[0069] When there is a significant difference in the coordinates of any sampling point compared to the sampling points with the same serial number in all historical cycles, it means that the probability of abnormal changes in the indicator diagram caused by temperature at the current moment is higher; however, since the shock absorber is in continuous operation, the change in its internal temperature is nonlinear, and the start and end temperatures in different cycle time periods divided by the above steps are significantly different. The actual temperature change has different impacts on each cycle. Therefore, it is easy to misjudge the quality inspection of shock absorbers with assembly problems based only on the above calculated possibilities, and it is necessary to eliminate the impact of temperature changes on quality inspection.

[0070] According to the above steps, the temperature influence possibility of each sampling point in the current cycle and the historical cycle is obtained; the temperature difference between each sampling point in the current cycle and the sampling point with the same sequence number in the historical cycle is calculated. If the number of sampling points in the current cycle is less than or equal to the historical cycle, the temperature difference between each sampling point in the current cycle and the sampling point with the same sequence number in the historical cycle is calculated. If the number of sampling points in the current cycle is greater than the historical cycle, the temperature difference between the sampling points with a sequence number greater than the maximum sequence number of the sampling points in the historical cycle and the sampling point with the maximum sequence number in the historical cycle is calculated, thereby obtaining the temperature difference of each sampling point with a sequence number in the current cycle. In this embodiment, the temperature difference is calculated by taking the absolute value of the difference between the temperatures of the two sampling points.

[0071] For the current cycle and any historical cycle, a coordinate system is constructed with the temperature difference at the sampling point in the current cycle as the horizontal axis and the temperature impact possibility of the sampling point as the vertical axis. The sampling point in the current cycle is a two-dimensional point and is recorded as a data point in the coordinate system.

[0072] Analysis shows that because the impact of temperature changes on shock absorbers is continuous and nonlinear, despite a large temperature difference between two different cycles (if the two cycles are not adjacent), the ultimate temperature effect on the shock absorber's damping force is approximately linear within a local time period. Therefore, in the coordinate system constructed above, the temperature influence will cause all data points within the two cycles to be densely distributed within a certain range. Conversely, for equipment related to assembly, it will cause it to be uneven on the dynamometer diagram, and based on the coordinate system constructed above, the data points may be distributed farther outward. At the same time, due to the different temperatures and effects between different cycles, the clustering centers of data points in different cycles will vary. However, the impact caused by assembly issues is the same, so the data points affected by assembly issues will be more dispersed when compared between different cycles.

[0073] The coordinate system formed by the current period and any historical period is recorded as the temperature-related coordinate system. For the temperature-related coordinate system, any data point is taken as the center point, and the Euclidean distance between all data points and the center point is calculated as the overall distance of the center point. The overall distance of all data points is obtained, and the data point corresponding to the minimum overall distance is recorded as the cluster center. The Euclidean distance between each data point and the cluster center is calculated as the distance from each data point to the cluster center. The larger the distance, the greater the possibility of being affected by the assembly problem.

[0074] Several historical periods before the current period are selected for analysis. In this embodiment, 10 historical periods before the current period are selected.

[0075] For the temperature-related coordinate system composed of the current period and each historical period, sort the distance from each data point in the temperature-related coordinate system to the distance center in descending order and label the data points; use the temperature difference as the horizontal axis and the temperature impact possibility as the vertical axis to reconstruct an empty coordinate system and record it as the temperature impact coordinate system; add the data points of all temperature-related coordinate systems to the temperature impact coordinate system according to the number of the data points, and each time a data point is added, a data point is added to each temperature-related coordinate system; when the data points with the same serial number are added, it is considered as an iteration, and a new temperature impact coordinate system is obtained each time an iteration is completed, until all the data points of the temperature-related coordinate systems are added to the temperature impact coordinate system. In this process, a temperature impact coordinate system is obtained after each iteration is completed, and several temperature impact coordinate systems are obtained.

[0076] Taking this embodiment as an example, 10 historical periods are selected, i.e., there are 10 temperature-related coordinate systems. After labeling the data points in each temperature-related coordinate system, all data points labeled 1 in the temperature-related coordinate system are added to the temperature-affected coordinate system. The temperature-affected coordinate system now has 10 data points, which is now recorded as the first temperature-affected coordinate system. The data point labeled 2 is then added to the first temperature-affected coordinate system, resulting in 20 data points in the temperature-affected coordinate system, which is now recorded as the second temperature-affected coordinate system. This continues until all data points labeled G in the temperature-related coordinate system are added, at which point there are 10*G data points in the temperature-affected coordinate system.

[0077] Calculate the Euclidean distances between all data points in each temperature-affected coordinate system, and use the mean of all Euclidean distances as the mean distance of the temperature-affected coordinate system; all data points in the temperature-affected coordinate system corresponding to the minimum value of the mean distance are recorded as outliers.

[0078] When there is no problem with the assembly of the shock absorber itself, the number of separation points is relatively large when the separation point screening is performed based on the above method. However, according to actual analysis, the changes in the indicator diagram caused by the assembly process are local, so the number of separation points is usually small.

[0079] The average number of sampling points in all historical periods is obtained, and the impact value is obtained based on the ratio of the outlier point to the number of sampling points in all historical periods.

[0080] The expression of the impact value is:

[0081] , represents the number of outliers, represents the number of historical periods, represents the mean number of sampling points in all historical periods, Indicates the impact value.

[0082] The more outliers there are, the less affected the situation is.

[0083] For each outlier point, there is a corresponding serial number value in the current cycle, and the variance of the serial number values ​​of all outliers is calculated. The smaller the value, the higher the probability that the current corresponding serial number is affected by the assembly problem.

[0084] For each outlier point, in the temperature-related coordinate system where the outlier point is located, the greater the distance value from the outlier point to the cluster center, the higher the probability of being affected by the assembly problem. The distance value from the outlier point to the cluster center is recorded as the distance parameter of the outlier point. Therefore, based on the influence value, the variance of the sequence number values ​​of all outliers, and the distance parameter of the outlier point, the probability that the shock absorber is affected by the assembly problem is obtained:

[0085] , represents the variance of the ordinal values ​​of all outliers, Indicates the impact value, represents the distance parameter of the kth outlier point, represents the number of outliers, Indicates the probability that the shock absorber is affected by an assembly problem.

[0086] At this point, the probability that the shock absorber is affected by the assembly problem in the current cycle is obtained.

[0087] Step S004 : performing quality inspection on the shock absorber based on the probability that the shock absorber is affected by the assembly problem.

[0088] According to the above method, the probability of the shock absorber being affected by the assembly problem in each cycle is obtained, and the probability of the shock absorber being affected by the assembly problem in all cycles is linearly normalized. When the normalized value is greater than the preset threshold, it means that during the detection process, the entire shock absorber equipment is likely to have an assembly problem after removing the influence of temperature changes. In this embodiment, the preset threshold is 0.7.

[0089] If the possibility of an assembly problem is high, first disassemble the shock absorber and check whether there are any omissions in the assembly process for internal parts such as pistons, seals, oil, etc., and conduct the same quality inspection on other shock absorbers of the same batch. If abnormal dynamometer diagrams still appear with similar strokes and positions, it can be determined that there is a problem in the assembly process, and targeted assembly adjustments can be made to ensure that all subsequent components are correctly installed and meet the predetermined torque and clearance requirements.

[0090] Based on the same inventive concept as the above method, an embodiment of the present invention also provides an automobile shock absorber assembly quality inspection system, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above-mentioned automobile shock absorber assembly quality inspection methods.

[0091] Based on the same inventive concept as the above method, an embodiment of the present invention also provides an automobile shock absorber assembly quality inspection device, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above-mentioned automobile shock absorber assembly quality inspection methods.

[0092] An automobile shock absorber assembly quality inspection device such as Figure 2 As shown, Figure 2 In the figure, 1 is a quick-change fixture, 2 is a lifting column, 3 is a shock absorber, 4 is a temperature sensor, 5 is a probe, 6 is a displacement slider, 7 is a lifting shaft, 8 is a displacement and technical sensor, 9 is a drive motor, 10 is a pull wire, 11 is a support wheel, 12 is a cylinder, and 13 is a high-speed central processing unit.

[0093] The shock absorber is secured to a quick-change fixture and a displacement slider, which also has a snap. Based on the actual parameters calibrated during the shock absorber design process, the height of the lifting column is adjusted so that the shock absorber is within its effective travel range and that the midpoint of its travel initially coincides with the midpoint of the excitation travel. The drive motor is activated and its power adjusted, allowing the lifting shaft to perform high-speed vertical displacement, thereby driving the displacement slider, which in turn generates varying amounts of vertical pressure on the shock absorber, allowing for relevant excitation testing. Displacement and counting sensors collect corresponding data, enabling force measurements at multiple speed points. A high-speed central processing unit detects the damping force of the shock absorber and indicates the corresponding maximum and minimum damping force values. An integrated temperature sensor 4 is designed, comprising a probe 5. The probe 5 is long enough to prevent it from falling due to tension during shock absorber 3 testing. A thermocouple is used at the contact surface with the shock absorber 3 to collect temperature data. By evenly distributing the probes 5 vertically, relevant temperature data is acquired. A lateral force application device, consisting of a cable 10, a support wheel 11, and a cylinder 12, is located on the other side. The cable 10 passes over the support wheel 11 and connects to the cylinder 12, with the other side fixed to the shock absorber 3. When the cylinder 12 is activated, the cable 10 pulls on the shock absorber 3, generating a lateral force that simulates actual car cornering scenarios and improves the authenticity of the actual data.

[0094] It should be noted that the above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and should all be included in the scope of protection of the present application.

[0095] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A method for quality inspection of automobile shock absorber assembly, characterized in that: The method comprises the following steps: The displacement distance, damping force and temperature of each sampling point are obtained based on different sensors, and the dynamometer diagram is constructed according to the displacement distance and damping force of the sampling point; The time taken by the shock absorber piston to move from the top dead center to the bottom dead center and then back to the top dead center is recorded as a cycle; all sampling points in each cycle are sorted in chronological order, the sequence number of each sampling point is obtained, and the cycle difference between the two cycles is calculated based on the length of the two cycles; the current cycle to be tested is recorded as the current cycle, and the previous cycle is recorded as the historical cycle; the temperature impact trend of the sampling point is obtained based on the difference between the sampling points of the current cycle and the historical cycle; the temperature impact possibility of the sampling point of the current cycle is obtained based on the cycle difference between the current cycle and the historical cycle and the temperature impact trend of the sampling point of the current cycle; A preset number of historical periods before the current period are selected; the temperature difference between the sampling points in the current period and each historical period and the possibility of temperature influence are used as the horizontal and vertical coordinates to construct a temperature-related coordinate system for the current period and each historical period; for each temperature-related coordinate system, the cluster center is determined based on the minimum distance between all data points; the data points are numbered from largest to smallest according to their distance from the cluster center, and all data points with the same number in the temperature-related coordinate system are added to the new coordinate system in order of the number to form several temperature-affected coordinate systems; the outliers are determined based on the distance between the data points in the temperature-affected coordinate system, and the influence value is determined by the ratio of the number of outliers to the number of all sampling points in the historical period; the probability that the shock absorber is affected by the assembly problem is obtained based on the variance of the ordinal value of the outliers in the current period, the influence value, and the distance between the outliers and the cluster center; Determine whether the shock absorber has any abnormalities based on the probability that the shock absorber is affected by assembly problems, and perform quality inspection on the shock absorber.

2. The automobile shock absorber assembly quality inspection method according to claim 1, characterized in that: The method for calculating the cycle difference is to calculate the absolute value of the difference between the cycle lengths of two cycles.

3. The automobile shock absorber assembly quality inspection method according to claim 1, characterized in that: The method for obtaining the temperature influence trend of the sampling point based on the difference between the sampling points of the current cycle and the historical cycle is: If the number of sampling points in the current cycle is less than or equal to the number of sampling points in the historical cycle, the difference between each sampling point in the current cycle and the sampling point with the same serial number in the historical cycle is calculated to obtain the temperature influence trend of the sampling point in the current cycle; If the number of sampling points in the current cycle is greater than the number of sampling points in the historical cycle, the difference between the last sampling point in the historical cycle and the remaining uncalculated sampling points in the current cycle is used to obtain the temperature impact trend of the remaining sampling points in the current cycle; The temperature impact trend is calculated by calculating the Euclidean distance between two sampling points.

4. The automobile shock absorber assembly quality inspection method according to claim 1, characterized in that: The method for obtaining the temperature influence possibility of the current cycle sampling point based on the cycle difference between the current cycle and the historical cycle and the temperature influence trend of the current cycle sampling point is: The cycle difference between the current cycle and the historical cycle is recorded as the temperature impact weight of the current cycle; The possibility of temperature impact is positively correlated with the temperature impact weight of the current period and the temperature impact trend of the sampling point in the current period.

5. The automobile shock absorber assembly quality inspection method according to claim 1, characterized in that: The method for constructing the temperature-related coordinate system of the current period and each historical period using the temperature difference of the sampling points in the current period and each historical period and the possibility of temperature influence as the horizontal and vertical coordinates is as follows: Calculate the temperature difference between each sampling point in the current cycle and the sampling points in the historical cycle as the temperature difference of each sampling point in the current cycle; If the number of sampling points in the current cycle is less than or equal to that in the historical cycle, the temperature difference between each sampling point in the current cycle and the sampling point with the same sequence number in the historical cycle is calculated; If the number of sampling points in the current cycle is greater than that in the historical cycle, then for the sampling point with a sequence number greater than the maximum sequence number of the sampling points in the historical cycle, calculate the temperature difference between it and the sampling point with the maximum sequence number in the historical cycle; The temperature difference was calculated as the absolute value of the difference between the temperatures at two sampling points; Let the temperature difference of the sampling points be the horizontal axis and the temperature influence possibility of the sampling points be the vertical axis to construct a coordinate system. For the current period and any historical period, all sampling points corresponding to the current period are added to the coordinate system as the temperature-related coordinate system of the current period and any historical period.

6. The automobile shock absorber assembly quality inspection method according to claim 1, characterized in that: The method of adding the data points with the same labels in all temperature-related coordinate systems to a new coordinate system in the order of the labels to form several temperature-affected coordinate systems is as follows: Using the temperature difference as the horizontal axis and the temperature influence possibility as the vertical axis, an empty coordinate system is reconstructed and recorded as the temperature influence coordinate system; the data points of all temperature-related coordinate systems are added to the temperature influence coordinate system according to the number of the data points. Each time a data point is added, one data point is added to each temperature-related coordinate system; when the data points with the same serial number are added, it is considered an iteration, and a new temperature influence coordinate system is obtained after each iteration is completed, until all the data points of the temperature-related coordinate systems are added to the temperature influence coordinate system.

7. The automobile shock absorber assembly quality inspection method according to claim 1, characterized in that: The method for determining the outlier points based on the distance between data points in the temperature influence coordinate system and determining the impact value based on the ratio of the number of outlier points to the number of all sampling points in the historical period is as follows: Calculate the Euclidean distances between all data points in each temperature-affected coordinate system, and take the mean of all Euclidean distances as the mean distance of the temperature-affected coordinate system; record all data points in the temperature-affected coordinate system corresponding to the minimum value of the mean distance as outliers; The expression of the impact value is: , represents the number of outliers, represents the number of historical periods, represents the mean number of sampling points in all historical periods, Indicates the impact value.

8. The automobile shock absorber assembly quality inspection method according to claim 1, characterized in that: The method for obtaining the probability that the shock absorber is affected by the assembly problem based on the variance of the sequence number value of the outlier point in the current cycle, the influence value, and the distance between the outlier point and the cluster center is: , represents the variance of the ordinal values ​​of all outliers, Indicates the impact value, represents the distance parameter of the kth outlier point, represents the number of outliers, Indicates the probability that the shock absorber is affected by an assembly problem.

9. An automobile shock absorber assembly quality inspection system, which implements the automobile shock absorber assembly quality inspection method according to claim 1, characterized in that: The system comprises: A data acquisition module is used to obtain the displacement distance, damping force and temperature of each sampling point based on different sensors, and to construct a dynamometer diagram based on the displacement distance and damping force of the sampling point; The temperature impact possibility acquisition module is used to record the time taken by the shock absorber piston from the top dead center to the bottom dead center and then back to the top dead center as a cycle; sort all sampling points in each cycle in chronological order, obtain the sequence number of each sampling point, and calculate the cycle difference between the two cycles based on the lengths of the two cycles; record the current cycle to be detected as the current cycle, and the previous cycle as the historical cycle; obtain the temperature impact trend of the sampling point based on the difference between the sampling points of the current cycle and the historical cycle; and obtain the temperature impact possibility of the sampling point of the current cycle based on the cycle difference between the current cycle and the historical cycle and the temperature impact trend of the sampling point of the current cycle; The module for obtaining the probability that the shock absorber is affected by assembly problems is used to select a preset number of historical periods before the current period; use the temperature difference between the sampling points in the current period and each historical period and the possibility of temperature influence as the horizontal and vertical coordinates to construct a temperature-related coordinate system for the current period and each historical period; for each temperature-related coordinate system, determine the cluster center based on the minimum distance between all data points; label the data points from large to small according to their distance from the cluster center, and add all data points with the same label in the temperature-related coordinate system to the new coordinate system in the order of the label to form several temperature-affected coordinate systems; determine the outliers based on the distance between the data points in the temperature-affected coordinate system, and determine the influence value based on the ratio of the number of outliers to the number of all sampling points in the historical period; and obtain the probability that the shock absorber is affected by the assembly problem based on the variance of the serial number value of the outliers in the current period, the influence value, and the distance between the outliers and the cluster center. The quality inspection module is used to determine whether the shock absorber has any abnormality based on the probability that the shock absorber is affected by the assembly problem, and to perform quality inspection on the shock absorber.

10. An automobile shock absorber assembly quality inspection device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the automobile shock absorber assembly quality inspection method as described in any one of claims 1 to 8 are implemented.

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