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

Abstract

The invention relates to the technical field of quality detection, in particular to an automobile shock absorber assembly quality inspection device, method and system. The method comprises the following steps: acquiring a displacement distance, a damping force and a temperature of a sampling point; presetting a period, and obtaining the temperature influence possibility of the sampling points in the period according to the difference of different periods and the difference of the sampling points between the periods; selecting a plurality of historical periods, and constructing a temperature-related coordinate system according to the temperature difference between the periods and historical period sampling points and the temperature influence possibility; clustering and numbering the coordinate system, and forming a temperature influence coordinate system by the sampling points of the current period and each historical period according to a numbering sequence; determining departure points based on the temperature influence coordinate system, and obtaining the probability that the shock absorber is influenced by the assembly problem according to the number of departure points, the variance of serial numbers and the distance; and quality inspection is carried out on the shock absorber based on this. According to the invention, the accuracy of the actual quality inspection of the shock absorber is improved.

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 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 damping force of the shock absorber increases or decreases with the relative speed of the frame and the axle, thereby improving the driving stability 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, which will affect the fluidity of the oil and the stability of the damping force, and will also make 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, the present application provides a vehicle shock absorber assembly quality inspection device, quality inspection method and system, and the technical solutions adopted are as follows: In a first aspect, the present application proposes a method for quality inspection of automobile shock absorber assembly, the method comprising 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 return to the top dead center is recorded as a cycle; all sampling points in each cycle are sorted in chronological order, the serial number of each sampling point is obtained, and the cycle difference between the two cycles is calculated according to the length of the two cycles; the current cycle to be detected is recorded as the current cycle, and the previous cycle is recorded as the historical cycle; the temperature influence trend of the sampling point is obtained according to the difference between the sampling points of the current cycle and the historical cycle; the temperature influence possibility of the sampling point of the current cycle is obtained according to the cycle difference between the current cycle and the historical cycle and the temperature influence trend of the sampling point of the current cycle; Select a preset number of historical cycles before the current cycle; use the temperature difference between the sampling points in the current cycle and each historical cycle and the possibility of temperature influence as the horizontal and vertical coordinates to construct the temperature-related coordinate system of the current cycle and each historical cycle; for each temperature-related coordinate system, determine the cluster center according to the minimum distance between all data points; label the data points from large to small according to the distance between them and the cluster center, and add all the data points with the same label in the temperature-related coordinate system to the new coordinate system in the order of the label each time to form several temperature-affected coordinate systems; determine the divergence point according to the distance between the data points in the temperature-affected coordinate system, and determine the influence value by the ratio of the number of divergence points to the number of all sampling points in the historical cycle; obtain the probability that the shock absorber is affected by the assembly problem according to the variance of the serial number value of the divergence point in the current cycle, the influence value and the distance between the divergence point and the cluster center; Determine whether the shock absorber is abnormal based on the probability that the shock absorber is affected by assembly problems, and perform quality inspection on the shock absorber.

[0005] 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 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 divergent points are screened based on the coordinate system after eliminating the temperature influence, thereby inferring the section of the original dynamometer diagram affected by the assembly problem; 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.

[0006] In one embodiment, the cycle difference is calculated by calculating the absolute value of the difference between the cycle lengths of two cycles.

[0007] In one embodiment, the method for obtaining the temperature influence trend of the sampling point according to 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 influence trend of the remaining sampling points in the current cycle; The calculation method for temperature influence trend is to calculate the Euclidean distance between two sampling points.

[0008] In one embodiment, the method for obtaining the possibility of temperature influence of the current cycle sampling point according to 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 of the current period.

[0009] In one embodiment, the method of constructing the temperature-related coordinate system of the current cycle and each historical cycle by using the temperature difference of the sampling points in the current cycle and each historical cycle and the possibility of temperature influence as the horizontal and vertical coordinates is: 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 number greater than the maximum number of sampling points in the historical cycle, calculate the temperature difference between it and the sampling point with the maximum number in the historical cycle; The temperature difference was calculated as the absolute value of the difference between the temperatures at two sampling points; The temperature difference of the sampling points is used as the horizontal axis, and the possibility of temperature influence of the sampling points is used as 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.

[0010] 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: Using the temperature difference as the horizontal axis and the possibility of temperature influence 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 numbers 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 regarded as an iteration, and a new temperature influence coordinate system is obtained after each iteration, until all the data points of all temperature-related coordinate systems are added to the temperature influence coordinate system.

[0011] In one embodiment, the method of determining the outlier points according to the distance between the data points in the temperature influence coordinate system and determining the impact value according to the ratio of the number of outlier points to the number of all sampling points in the historical period is: 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 divergent points, represents the number of historical periods, represents the mean number of sampling points in all historical periods, Indicates the impact value.

[0012] In one embodiment, the method for obtaining the probability that the shock absorber is affected by the assembly problem according to the variance of the sequence 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 divergent points, Indicates the probability that the shock absorber is affected by an assembly problem.

[0013] In a second aspect, the present application also provides a vehicle shock absorber assembly quality inspection system, the system comprising: 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 form a dynamometer diagram according to the displacement distance and damping force of the sampling point; The temperature influence 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 the sampling points in each cycle in chronological order, obtain the serial number of each sampling point, and calculate the cycle difference between the two cycles according to the length 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 influence trend of the sampling point according to the difference between the sampling points of the current cycle and the historical cycle; obtain the temperature influence possibility of the sampling point of the current cycle according to the cycle difference between the current cycle and the historical cycle and the temperature influence trend of the sampling point of the current cycle; The probability acquisition module of the shock absorber being affected by the assembly problem is used to select a preset number of historical cycles before the current cycle; use the temperature difference of the sampling points in the current cycle and each historical cycle and the possibility of temperature influence as the horizontal and vertical coordinates to construct the temperature-related coordinate system of the current cycle and each historical cycle; for each temperature-related coordinate system, determine the cluster center according to the minimum distance between all data points; label the data points from large to small according to the distance between them and the cluster center, and add all the data points with the same label in the temperature-related coordinate system to the new coordinate system in the order of the label each time to form a number of temperature-affected coordinate systems; determine the outlier point according to the distance between the data points in the temperature-affected coordinate system, and determine the influence value by the ratio of the number of outlier points to the number of all sampling points in the historical cycle; obtain the probability of the shock absorber being affected by the assembly problem according to the variance of the serial number value of the outlier point in the current cycle, the influence value and the distance between the outlier point and the cluster center; The quality inspection module is used to determine whether the shock absorber has an abnormality based on the probability that the shock absorber is affected by the assembly problem, and to perform quality inspection on the shock absorber.

[0014] 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.

[0015] The beneficial effects of this application are: 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 two periods, thereby judging the possibility of temperature influence, and reconstructs a new coordinate system based on the possibility and the temperature difference, compares the aggregation of data points between different periods, and eliminates the influence of nonlinear temperature changes on the actual dynamometer diagram changes based on this method, and screens the divergent points based on the coordinate system after eliminating the temperature influence, and then infers 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, thereby improving the accuracy of actual quality inspection of shock absorbers. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. 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 creative work.

[0017] 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; Figure 2 This is a schematic diagram of a quality inspection device for automobile shock absorber assembly. DETAILED DESCRIPTION

[0018] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of the specific implementation, structure, features and effects of an automobile shock absorber assembly quality inspection device, quality inspection method and system proposed in the present application in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0019] 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.

[0020] An automobile shock absorber assembly quality inspection device, quality inspection method and system embodiment: The specific scheme of an automobile shock absorber assembly quality inspection device, quality inspection method and system provided by the present application is described in detail below with reference to the accompanying drawings.

[0021] See also Figure 1 , which shows an automobile shock absorber assembly quality inspection device, quality inspection method and system flow chart provided by an embodiment of the present application, the method comprising the following steps: Step S001, obtaining the displacement distance, damping force and temperature of the sampling point, and forming a dynamometer diagram.

[0022] The counting sensor counts each time the piston moves, and each count is used as a sampling point. The displacement sensor collects the displacement distance of each sampling point when the shock absorber piston moves, and the high-speed central processor detects the damping force of each sampling point in the shock absorber. The displacement distance of all sampling points and the corresponding damping force of the shock absorber at this time are used to draw the shock absorber's indicator diagram.

[0023] The shock absorber will generate friction during operation, which will cause the temperature of the entire shock absorber to rise. By detecting the temperature of the shock absorber, it can be evaluated whether there is an 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.

[0024] The displacement and counting sensor collects and counts the displacement of the piston in the shock absorber, and the high-speed central processor detects the damping force of the shock absorber. The displacement of all counted pistons and the corresponding damping force of the shock absorber are plotted on the shock absorber's dynamometer. The horizontal axis of the dynamometer is the displacement distance of each sampling point, and the vertical axis is the damping force corresponding to each sampling point.

[0025] At this point, the dynamometer diagram of the shock absorber and the temperature of each sampling point are obtained.

[0026] Step S002, sorting the sampling points of each cycle, and obtaining the temperature influence possibility of each cycle according to the difference between two cycles and the difference between the sampling points of the two cycles.

[0027] Temperature changes affect the viscosity of the oil inside the shock absorber, which in turn affects the size of the damping force. When the temperature rises, the oil viscosity decreases and the damping force decreases; when the temperature drops, the oil viscosity increases and the damping force increases. This change will be reflected on the indicator diagram, which is manifested as changes in the shape and height of the damping force curve. Among them, temperature changes may also change the damping characteristics of the shock absorber, so the curve on the indicator diagram is no longer smooth, and nonlinear segments or mutation points may appear. In the process of quality inspection of the shock absorber, due to improper assembly, air enters the shock absorber, bubbles will be formed, affecting the fluidity of the oil and the stability of the damping force, and also making the indicator diagram not smooth; the changes in the indicator diagram caused by assembly and the changes in the indicator diagram caused by temperature have the same data characteristics, so it is easy to cause misjudgment, resulting in a reduction in the accuracy of the actual quality inspection of the shock absorber.

[0028] Therefore, it is necessary to analyze the abnormal curve of the dynamometer diagram to distinguish whether the change of the dynamometer diagram is caused by assembly or temperature.

[0029] The shock absorber piston will go through a process from the top dead center to the bottom dead center and then back to the top dead center. The time corresponding to this process is recorded as a cycle. The damping force will change over time, so there will be certain differences in different cycles on the indicator diagram, but the displacement distance of the piston is the same. In the absence of external influences, the number of sampling points corresponding to different cycles is the same.

[0030] 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 change of the sampling point in each cycle should be small, while the length of its own cycle remains unchanged; when affected by temperature, the displacement distance of the sampling point changes greatly, and the movement speed of the piston is faster, that is, the time period for the piston to complete a cycle of movement becomes smaller, and there is a certain difference in the cycle length.

[0031] For any two cycles, the cycle difference between the two cycles is calculated. The larger the cycle difference, the greater the cycle variation between the two cycles, and the higher the possibility of temperature influence. In this embodiment, the cycle difference between the two cycles is calculated by calculating the absolute value of the difference between the cycle lengths of the two cycles.

[0032] Select a historical cycle from the historical data; record the cycle to be detected as the current cycle, and obtain the temperature influence trend of the sampling points based on the difference between the sampling points with the same sequence number in the current cycle and the historical cycle. If the number of sampling points in the current cycle is greater than that in the historical cycle, the temperature influence trend of the remaining sampling points in the current cycle is obtained based on the difference between the last sampling point in the historical cycle and the remaining uncalculated sampling points in the current cycle, that is, each sampling point in the current cycle has a corresponding sampling point in the historical cycle.

[0033] For example, if the sampling point serial numbers of the current cycle are {1, 2, 3, 4, 5}, and the sampling point serial numbers of the historical cycle are {1, 2, 3, 4}, then when calculating the sampling points with the same serial numbers, the temperature influence 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}.

[0034] 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.

[0035] The temperature influence possibility of the sampling point in the current period is obtained according to the temperature influence weight of the current period and the temperature influence trend of the sampling point in the current period.

[0036] 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 of the current period.

[0037] 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.

[0038] Preferably, in this embodiment, the cycle difference between the current cycle and the historical cycle is calculated, and the cycle difference is used as the temperature impact weight of the current cycle; the product of the temperature impact weight of the current cycle and the temperature impact trend of each sampling point in the current cycle is used as the temperature impact possibility of each sampling point in the current cycle.

[0039] At this point, the temperature influence possibility of each sampling point in the current cycle is obtained.

[0040] Step S003, construct a temperature-related coordinate system based on the temperature difference and temperature influence possibility of the sampling points in the current cycle and the historical cycle; cluster and sort the data points therein, and construct a temperature influence coordinate system with the data points with the same sequence number in all the temperature-related coordinate systems in the sorted order; determine the divergence points 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 divergence points, the variance of the divergence point sequence numbers, and the distance of the divergence points.

[0041] 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 a continuous working process, 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, and 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.

[0042] According to the above steps, the possibility of temperature influence 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, for the sampling points with a sequence number greater than the maximum sequence number of the sampling points in the historical cycle, the temperature difference between them and the sampling point with the maximum sequence number in the historical cycle is calculated, thereby obtaining the temperature difference of the sampling points with each sequence number in the current cycle; in this embodiment, the temperature difference is calculated by the absolute value of the difference between the temperatures of two sampling points.

[0043] For the current cycle and any historical cycle, the temperature difference of the sampling point in the current cycle is used as the horizontal axis, and the temperature influence possibility of the sampling point is used as the vertical axis to construct a coordinate system. The sampling point in the current cycle is a two-dimensional point, which is recorded as a data point in the coordinate system.

[0044] According to the analysis, since the impact of temperature change on the shock absorber is continuous and nonlinear, although there is a large temperature difference between two different cycles (if the two cycles are not adjacent), the final temperature impact on the damping force of the shock absorber is approximately linear in the local time period. Therefore, in the above-constructed coordinate system, the temperature influence will cause all data points in the two cycles to be densely distributed within a certain range. On the contrary, for related equipment problems caused by assembly, it will make it unsmooth on the indicator diagram, and based on the above-constructed coordinate system, the data points may be distributed on the outer side; at the same time, due to the different temperatures and influences between different cycles, the aggregation centers of data points in different cycles are different, while the influence caused by assembly problems is the same, so the data points affected by assembly problems will be more scattered in the comparison process between different cycles.

[0045] The coordinate system formed by the current cycle and any historical cycle 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, and 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.

[0046] Several historical periods before the current period are selected for analysis. In this embodiment, 10 historical periods before the current period are selected.

[0047] For the temperature-related coordinate system formed by the current cycle and each historical cycle, 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 possibility of temperature influence as the vertical axis to reconstruct an empty coordinate system recorded as the temperature influence coordinate system; add the data points of all temperature-related coordinate systems to the temperature influence coordinate system according to the numbers of the data points, and each time a data point is added, each temperature-related coordinate system adds a data point; when the data points with the same serial number are added, it is regarded as 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. In this process, a temperature influence coordinate system is obtained after each iteration is completed, thereby obtaining several temperature influence coordinate systems.

[0048] Taking this embodiment as an example, this embodiment selects 10 historical periods, that is, there are 10 temperature-related coordinate systems. After labeling the data points in each temperature-related coordinate system, the data points labeled 1 in all temperature-related coordinate systems are added to the temperature-affected coordinate system; there are 10 data points in the temperature-affected coordinate system, which is now recorded as the first temperature-affected coordinate system. Then, the data point labeled 2 is added to the first temperature-affected coordinate system, and there are 20 data points in the temperature-affected coordinate system, which is now recorded as the second temperature-affected coordinate system, until the data points labeled G in the temperature-related coordinate system are added, and at this time there are 10*G data points in the temperature-affected coordinate system.

[0049] The Euclidean distances between all data points in each temperature-affected coordinate system are calculated, and the mean of all Euclidean distances is taken 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.

[0050] When there is no problem in the assembly of the shock absorber itself, the number of separation points is large when the separation point screening is performed based on the above method. However, according to actual analysis, the change of the indicator diagram caused by the assembly process is local, so the number of separation points is usually small.

[0051] 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.

[0052] The expression of the impact value is: , represents the number of divergent points, represents the number of historical periods, represents the mean number of sampling points in all historical periods, Indicates the impact value.

[0053] The more the number of divergent points is, the less affected the situation is.

[0054] For each divergent point, there is a corresponding serial number value in the current cycle, and the variance of the serial number values ​​of all the divergent points is calculated. The smaller the value, the higher the probability that the current corresponding serial number is affected by the assembly problem.

[0055] 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 of the shock absorber being affected by the assembly problem is obtained: , 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 divergent points, Indicates the probability that the shock absorber is affected by an assembly problem.

[0056] At this point, the probability that the shock absorber is affected by the assembly problem in the current cycle is obtained.

[0057] Step S004: Performing quality inspection on the shock absorber according to the probability that the shock absorber is affected by the assembly problem.

[0058] According to the above method, the probability that the shock absorber is affected by the assembly problem in each cycle is obtained, and it is linearly normalized based on the probability that the shock absorber is affected by the assembly problem in all cycles. 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.

[0059] If the possibility of assembly problems 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 are problems in the assembly process and targeted assembly adjustments can be made to ensure that all subsequent parts are installed correctly and meet the predetermined torque and clearance requirements.

[0060] 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, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor implements the steps of any one of the above-mentioned automobile shock absorber assembly quality inspection methods when executing the computer program.

[0061] 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, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, and 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.

[0062] A vehicle shock absorber assembly quality inspection device Figure 2 As shown, Figure 2Among them, 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 driving motor, 10 is a pull wire, 11 is a supporting wheel, 12 is a cylinder, and 13 is a high-speed central processing unit.

[0063] The shock absorber is fixed to the quick-change fixture and the displacement slider, wherein the displacement slider also has a buckle; according to the actual parameters calibrated during the design process of the shock absorber, the height of the lifting column is adjusted so that the shock absorber is within the effective stroke range, and the midpoint of the shock absorber stroke is basically coincident with the midpoint of the excitation stroke at the beginning. Start the drive motor and adjust the power, the lifting shaft can be displaced in the vertical direction at high speed, thereby driving the displacement slider to move, and then the shock absorber generates different pressures in the vertical direction, so as to carry out relevant excitation tests, and the corresponding data can be collected by the displacement and counting sensors, and the force value detection of multiple speed points can be performed, and the damping force value of the shock absorber can be detected by the high-speed central processor, and the corresponding maximum and minimum damping force values ​​are marked. An integrated temperature sensor 4 is designed, which includes a probe 5, the length of the probe 5 can ensure that it will not fall due to the tension during the detection process of the shock absorber 3, and the contact surface with the shock absorber 3 uses a thermocouple to collect the temperature state; by evenly distributing the probe 5 in the vertical direction, the relevant temperature data is obtained. The lateral force applying device composed of a cable 10, a support wheel 11, and a cylinder 12 is located on the other side, wherein the cable 10 passes through the support wheel 11 to connect the cylinder 12, and the other side is fixed on the shock absorber 3. When the cylinder 12 is started, the shock absorber 3 is pulled by the cable 10, thereby generating a lateral force, which is used to simulate actual scenes such as a car turning to improve the authenticity of the actual data.

[0064] 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 protection scope of the present application.

[0065] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and 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 return to the top dead center is recorded as a cycle; all sampling points in each cycle are sorted in chronological order, the serial number of each sampling point is obtained, and the cycle difference between the two cycles is calculated according to the length of the two cycles; the current cycle to be detected is recorded as the current cycle, and the previous cycle is recorded as the historical cycle; the temperature influence trend of the sampling point is obtained according to the difference between the sampling points of the current cycle and the historical cycle; the temperature influence possibility of the sampling point of the current cycle is obtained according to the cycle difference between the current cycle and the historical cycle and the temperature influence trend of the sampling point of the current cycle; Select a preset number of historical cycles before the current cycle; use the temperature difference between the sampling points in the current cycle and each historical cycle and the possibility of temperature influence as the horizontal and vertical coordinates to construct the temperature-related coordinate system of the current cycle and each historical cycle; for each temperature-related coordinate system, determine the cluster center according to the minimum distance between all data points; label the data points from large to small according to the distance between them and the cluster center, and add all the data points with the same label in the temperature-related coordinate system to the new coordinate system in the order of the label each time to form several temperature-affected coordinate systems; determine the divergence point according to the distance between the data points in the temperature-affected coordinate system, and determine the influence value by the ratio of the number of divergence points to the number of all sampling points in the historical cycle; obtain the probability that the shock absorber is affected by the assembly problem according to the variance of the serial number value of the divergence point in the current cycle, the influence value and the distance between the divergence point and the cluster center; Determine whether the shock absorber is abnormal 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 influence trend of the remaining sampling points in the current cycle; The calculation method for temperature influence trend is to calculate 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 possibility of temperature influence of the current cycle sampling point according to 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 of the current period.

5. The automobile shock absorber assembly quality inspection method according to claim 1, characterized in that: The method of constructing the temperature-related coordinate system of the current cycle and each historical cycle by using the temperature difference of the sampling points in the current cycle and each historical cycle and the possibility of temperature influence as the horizontal and vertical coordinates is: 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 number greater than the maximum number of sampling points in the historical cycle, calculate the temperature difference between it and the sampling point with the maximum number in the historical cycle; The temperature difference was calculated as the absolute value of the difference between the temperatures at two sampling points; The temperature difference of the sampling points is used as the horizontal axis, and the possibility of temperature influence of the sampling points is used as 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 a plurality of temperature-affected coordinate systems is as follows: Using the temperature difference as the horizontal axis and the possibility of temperature influence 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 numbers 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 regarded as an iteration, and a new temperature influence coordinate system is obtained after each iteration, until all the data points of all 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 of determining the outlier points according to the distance between the data points in the temperature influence coordinate system and determining the impact value according to the ratio of the number of outlier points to the number of all sampling points in the historical period is: 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 divergent points, 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 according to the variance of the sequence 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 divergent points, 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 as claimed in 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 form a dynamometer diagram according to the displacement distance and damping force of the sampling point; The temperature influence 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 the sampling points in each cycle in chronological order, obtain the serial number of each sampling point, and calculate the cycle difference between the two cycles according to the length 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 influence trend of the sampling point according to the difference between the sampling points of the current cycle and the historical cycle; obtain the temperature influence possibility of the sampling point of the current cycle according to the cycle difference between the current cycle and the historical cycle and the temperature influence trend of the sampling point of the current cycle; The probability acquisition module of the shock absorber being affected by the assembly problem is used to select a preset number of historical cycles before the current cycle; use the temperature difference of the sampling points in the current cycle and each historical cycle and the possibility of temperature influence as the horizontal and vertical coordinates to construct the temperature-related coordinate system of the current cycle and each historical cycle; for each temperature-related coordinate system, determine the cluster center according to the minimum distance between all data points; label the data points from large to small according to the distance between them and the cluster center, and add all the data points with the same label in the temperature-related coordinate system to the new coordinate system in the order of the label each time to form a number of temperature-affected coordinate systems; determine the outlier point according to the distance between the data points in the temperature-affected coordinate system, and determine the influence value by the ratio of the number of outlier points to the number of all sampling points in the historical cycle; obtain the probability of the shock absorber being affected by the assembly problem according to the variance of the serial number value of the outlier point in the current cycle, the influence value and the distance between the outlier point and the cluster center; The quality inspection module is used to determine whether the shock absorber has an 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 1-8 are implemented.

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