Crankshaft dynamic balance test data analysis method and system

Abstract

The invention relates to the technical field of data processing, in particular to a crankshaft dynamic balance test data analysis method and system. A crank pin of the crankshaft is connected with a first end of a connecting rod, a second end of the connecting rod is connected with a piston, and the method comprises the steps that the speed difference value of the two ends of the connecting rod at the target historical moment in the connecting rod direction is obtained, and the angular acceleration of the center of the crank pin rotating around the axis of the crankshaft at the target historical moment is obtained; determining a confidence coefficient value of the crank pin at the target historical moment according to the speed difference value and the angular acceleration value within a preset time period before the target historical moment so as to determine an unbalance degree value negatively related to the confidence coefficient value; and clustering the unbalance degree values at the plurality of historical moments, and outputting prompt information under the condition that the density value of a cluster to which the unbalance degree value at the target historical moment belongs is smaller than a preset density threshold value. According to the technical scheme, the balance abnormity of the crankshaft can be found in time.

Description

Technical Field

[0001] The present application relates to the field of data processing technology, and in particular to a method and system for analyzing crankshaft dynamic balancing test data. Background Art

[0002] The crankshaft is a vital mechanical component in the compressor. The main function of the crankshaft in a reciprocating compressor is to convert the rotational motion of the crankshaft into the reciprocating motion of the piston, so that the piston can complete the working cycle of inhaling, compressing and exhausting gas; the crankshaft includes a main journal, a crankpin, a crank arm and a balance block; the crankpin of the crankshaft can be connected to the piston through a connecting rod, and the crankpin causes the piston to reciprocate under the drive of the rotating crankshaft.

[0003] It is critical for the compressor that the crankshaft is in dynamic balance during operation. When the crankshaft is in an unbalanced state during operation, the rotating crankshaft will generate centrifugal force, causing the vibration amplitude or vibration frequency of the compressor to increase. The vibration will not only cause noise, but also shorten the service life of the compressor; therefore, it is necessary to perform a dynamic balance test on the crankshaft.

[0004] In order to realize the dynamic balance test of the crankshaft, the Chinese patent application document with publication number CN118583370A provides a crankshaft dynamic balancing correction device, including: a support structure equipped with a sensor, a belt for driving the crankshaft to rotate, and a bed; a symmetrically designed support base is installed on the bed, the support structure is installed on the side of the support base close to each other, the belt is located between the two support bases, a drive plate is installed on the bed, a drive motor is fixedly installed on the drive plate, a pulley is fixedly installed on the output end of the drive motor, and the belt is jointly mounted on the pulley and the crankshaft; a multi-station replacement mechanism is used to replace the crankshaft at multiple stations.

[0005] In the related art, the dynamic balancing test of the crankshaft is performed without the actual use of the crankshaft, so that the test results of the crankshaft are difficult to reflect the actual performance of the crankshaft in the compressor. Therefore, it is difficult to accurately perform the dynamic balancing test of the crankshaft. Summary of the Invention

[0006] In order to overcome the problem in related technologies that it is difficult to accurately implement dynamic balancing tests on crankshafts, the present application provides a crankshaft dynamic balancing test data analysis method and system.

[0007] According to a first aspect of an embodiment of the present application, a method for analyzing crankshaft dynamic balancing test data is provided, wherein a crankpin of the crankshaft is connected to a first end of a connecting rod, and a second end of the connecting rod is connected to a piston. The method comprises: for a target historical moment among multiple historical moments, obtaining a velocity difference value between the first and second ends of the connecting rod along the connecting rod direction at the target historical moment, and obtaining the magnitude of the angular acceleration of the center of the crankpin rotating around the axis of the crankshaft at the target historical moment; determining a confidence value of the crankpin at the target historical moment based on the velocity difference value and the magnitude of the angular acceleration within a preset time period before the target historical moment; the confidence value is used to characterize the consistency of the direction of change of the velocity difference value and the magnitude of the angular acceleration within the preset time period; determining an imbalance value negatively correlated with the confidence value based on the confidence value at the target historical moment; clustering the imbalance values ​​at the multiple historical moments to obtain multiple clusters, determining a density value of the cluster to which the imbalance value at the target historical moment belongs, and outputting a prompt message when the density value is less than a preset density threshold; the prompt message is used to indicate that there is an abnormality in the crankpin at the target historical moment.

[0008] In this way, by obtaining the speed difference value of the first end and the second end of the connecting rod along the connecting rod direction at the target historical moment, and obtaining the angular acceleration of the center of the crank pin rotating around the axis of the crankshaft at the target historical moment, the confidence value of the target historical moment is determined. When the crankshaft is unbalanced in a moving state, the crankpin connected to the crankshaft will jitter, so that the speed difference value at both ends of the connecting rod and the angular acceleration of the crankpin may have abnormal values. By clustering the imbalance values ​​that are negatively correlated with the confidence values, the performance of the crankshaft at different times can be compared, and the balance abnormality of the crankshaft can be discovered in time.

[0009] Compared with using equipment to test the crankshaft alone, since the two parameter values ​​of speed difference and angular acceleration are obtained during the actual use of the crankshaft, they can better reflect the actual performance of the crankshaft when working in the compressor. Therefore, the balance test of the crankshaft can be achieved more accurately.

[0010] Optionally, determining the crankpin confidence value at the target historical moment based on the velocity difference value and the angular acceleration within a preset time period before the target historical moment includes: ,in, is the confidence value of the crankshaft at the target historical moment, arctan is the inverse tangent function, n is the number of historical moments in the preset time period, is the speed difference value at the jth historical moment in the preset time period, is the average value of the speed difference within the preset time period, is the standard deviation of the speed difference value within the preset time period, is the angular acceleration at the jth historical moment in the preset time period, is the average value of the angular acceleration within the preset time period, is the standard deviation of the angular acceleration within the preset time period.

[0011] In this way, the more consistent the changing directions of the speed difference value and the angular acceleration magnitude within the preset time period are, the closer the confidence value is to 1; the less consistent the changing directions of the speed difference value and the angular acceleration magnitude within the preset time period are, the closer the confidence value is to 0. Therefore, the confidence value of the crank pin at the target historical moment can effectively characterize the consistency of the changing directions of the speed difference value and the angular acceleration magnitude within the preset time period.

[0012] Optionally, the confidence value of the crank pin at the target historical moment is determined based on the speed difference value and the angular acceleration within a preset time period before the target historical moment, including: normalizing the speed difference value within the preset time period before the target historical moment, and normalizing the angular acceleration within the preset time period before the target historical moment; determining the covariance between the normalized speed difference value and the normalized angular acceleration within the preset time period; and using the covariance as the confidence value of the crank pin at the target historical moment.

[0013] In this way, by determining the covariance between the normalized velocity difference value and the normalized angular acceleration magnitude within the preset time period, the consistency of the changing direction of the velocity difference value and the angular acceleration magnitude within the preset time period can be better determined; and since the velocity difference value and the angular acceleration magnitude for covariance calculation are normalized, the influence of the dimension of the parameter can also be avoided.

[0014] Optionally, based on the confidence value of the target historical moment, an imbalance value that is negatively correlated with the confidence value is determined, including: determining the velocity difference value of the target historical moment and the multiplication value of the angular acceleration; and taking the ratio of the multiplication value of the target historical moment to the confidence value of the target historical moment as the imbalance value of the target historical moment.

[0015] Optionally, the density value of the cluster to which the imbalance value at the target historical moment belongs is obtained in the following way: ,in, is the density value of the cluster to which the imbalance value at the target historical moment belongs, A is the number of imbalance values ​​in the cluster to which the imbalance value at the target historical moment belongs, It is the Euclidean distance between the ath imbalance value in the cluster to which the imbalance value at the target historical moment belongs and the center of the cluster.

[0016] In this way, the Euclidean distance between the imbalance value in the cluster to which the imbalance value at the target historical moment belongs and the center of the cluster is calculated. The larger the cumulative sum of the Euclidean distances, the lower the degree of aggregation of the cluster to which the imbalance value at the target historical moment belongs, and the more likely the crankshaft is in an unbalanced state at the target historical moment. Therefore, the determined density value can better characterize the probability that the crankshaft is in an unbalanced state at the target historical moment.

[0017] Optionally, the speed difference value between the first end and the second end of the connecting rod along the direction of the connecting rod at the target historical moment is obtained in the following manner: a first speed sensor is provided at the first end of the connecting rod to obtain a first speed of the first end of the connecting rod along the direction of the connecting rod at the target historical moment; a second speed sensor is provided at the second end of the connecting rod to obtain a second speed of the second end of the connecting rod along the direction of the connecting rod at the target historical moment; and the absolute value of the difference between the first speed and the second speed along the direction of the connecting rod at the target historical moment is used as the speed difference value corresponding to the target historical moment.

[0018] In this way, by obtaining the first speed and the second speed of the two ends of the connecting rod along the connecting rod direction, since the crank pin of the dynamically unbalanced crankshaft will generate additional centrifugal force, there is a difference between the first speed and the second speed. The absolute value of the difference between the first speed and the second speed is used as the speed difference value corresponding to the target historical moment, which helps to monitor the speed of the connecting rod so as to determine whether there is dynamic imbalance in the crankshaft.

[0019] Optionally, the magnitude of the angular acceleration of the center of the crank pin rotating around the axis of the crankshaft at the target historical moment is obtained in the following manner: obtaining the angular velocity information of the center of the crank pin along the axis of the crankshaft at the historical moment through a target sensor, and determining the magnitude of the angular acceleration of the center of the crank pin rotating around the axis of the crankshaft at the target historical moment based on the angular velocity information of the center of the crank pin along the axis of the crankshaft at multiple reference historical moments; wherein the reference historical moment is other historical moments adjacent to the target historical moment; and the target sensor includes at least one of an image sensor and an inertial measurement unit.

[0020] According to a second aspect of an embodiment of the present application, a crankshaft dynamic balancing test data analysis system is provided, comprising: a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the steps of the crankshaft dynamic balancing test data analysis method provided in the first aspect of the present application are implemented.

[0021] The technical solution provided by the embodiments of the present application may include the following beneficial effects: by obtaining the speed difference value of the first end and the second end of the connecting rod along the connecting rod direction at the target historical moment, and obtaining the angular acceleration of the center of the crank pin rotating around the axis of the crankshaft at the target historical moment, the confidence value of the target historical moment is determined. When the crankshaft is unbalanced in a moving state, the crankpin connected to the crankshaft will vibrate, so that the speed difference value at both ends of the connecting rod and the angular acceleration of the crankpin may have abnormal values. By clustering the imbalance values ​​that are negatively correlated with the confidence values, the performance of the crankshaft at different times can be compared, and the balance abnormality of the crankshaft can be discovered in time.

[0022] Compared with using equipment to test the crankshaft alone, since the two parameter values ​​of speed difference and angular acceleration are obtained during the actual use of the crankshaft, they can better reflect the actual performance of the crankshaft when working in the compressor. Therefore, the balance test of the crankshaft can be achieved more accurately.

[0023] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0025] Figure 1 is a flow chart showing a method for analyzing crankshaft dynamic balancing test data according to an exemplary embodiment; Figure 2 The figure is a schematic structural diagram of a crankshaft dynamic balancing test data analysis system according to an exemplary embodiment. DETAILED DESCRIPTION

[0026] Exemplary embodiments are described in detail herein, with examples illustrated in the accompanying drawings. When the following description refers to the drawings, identical numerals in different drawings represent identical or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with this application.

[0027] First, a brief introduction is given to the application scenario of the embodiment of the present application. In the application scenario of the present application, when the crankshaft of the compressor is unbalanced when in motion, the crankshaft will vibrate with a large amplitude or high frequency, thereby generating noise and threatening the service life of the compressor.

[0028] In order to perform a dynamic balance test on the crankshaft of the compressor, in the related art, audio near the crankshaft in motion can be collected by an audio collection device to determine whether the crankshaft is unbalanced. However, when determining whether the crankshaft is balanced through audio, it will be affected by environmental noise, making the result of the crankshaft balance test inaccurate.

[0029] Alternatively, in the related art, a balancing test can be performed on the crankshaft to be assembled using testing equipment. However, since the testing process is carried out outside the actual working state of the crankshaft, the test results are difficult to reflect the performance of the crankshaft when it is actually working in the compressor. Therefore, it is difficult to accurately perform a dynamic balancing test on the crankshaft.

[0030] In order to solve the above technical problems, the present invention provides a method and system for analyzing crankshaft dynamic balancing test data. Figure 1 FIG. 1 is a flow chart showing a method for analyzing crankshaft dynamic balancing test data according to an exemplary embodiment. Figure 1 As shown, the method includes the following steps.

[0031] In step S101, for a target historical moment among multiple historical moments, the speed difference value of the first end and the second end of the connecting rod along the connecting rod direction at the target historical moment is obtained, and the angular acceleration of the center of the crank pin along the axis of the crankshaft at the target historical moment is obtained.

[0032] The crankshaft in the compressor can rotate under the action of the motor, the crankpin of the crankshaft is connected to the first end of the connecting rod, and the second end of the connecting rod is connected to the piston; the center point of the crankpin can rotate with the axis of the crankshaft as the rotation axis, and the crankpin in a rotating state can push or pull the piston through the connecting rod, causing the piston to reciprocate, thereby achieving gas compression.

[0033] In an embodiment of the present application, the speed difference value between the first end and the second end of the connecting rod along the connecting rod direction at the target historical moment can be obtained when the motor of the compressor controls the crankshaft to move at a uniform speed. Since the crankshaft of the compressor may have dynamic imbalance, the actual performance of the crankshaft may be different from the expected performance of the set uniform speed state.

[0034] The angular acceleration of the center of the crankpin along the axis of the crankshaft at the target historical moment can be obtained when the compressor's motor controls the crankshaft to move at a uniform speed. Since the compressor's crankshaft may have dynamic imbalance, the actual performance of the crankpin of the crankshaft may differ from the expected performance in the set uniform speed state.

[0035] By installing sensors such as image sensors, distance sensors, laser sensors, speed sensors, and inertial measurement units in the crankshaft, it is possible to obtain speed information, angular velocity information, and angular acceleration information of each component connected to the crankshaft.

[0036] In one embodiment, the speed difference value between the first end and the second end of the connecting rod along the direction of the connecting rod at the target historical moment is obtained in the following manner: a first speed sensor is provided at the first end of the connecting rod to obtain a first speed of the first end of the connecting rod along the direction of the connecting rod at the target historical moment; a second speed sensor is provided at the second end of the connecting rod to obtain a second speed of the second end of the connecting rod along the direction of the connecting rod at the target historical moment; and the absolute value of the difference between the first speed and the second speed along the direction of the connecting rod at the target historical moment is used as the speed difference value corresponding to the target historical moment.

[0037] When the crankshaft in motion is in dynamic balance, the speeds of the two ends of the connecting rod connected to the crankpin along the connecting rod direction are the same; when the crankshaft in motion is dynamically unbalanced, the crankpin will generate additional centrifugal force, and the two ends of the connecting rod will be affected by the centrifugal force to different degrees at the same time, so there may be a difference in the speeds of the two ends of the connecting rod along the connecting rod direction. Therefore, by detecting the speeds of the two ends of the connecting rod along the connecting rod direction, it helps to determine whether the crankshaft has dynamic imbalance.

[0038] By means of a first speed sensor provided at the first end of the connecting rod, the first speed of the first end of the connecting rod along the direction of the connecting rod at the target historical moment can be obtained; the movement speed of the connection point between the crank pin and the connecting rod at the target historical moment can also be obtained through the speed sensor, and the first speed of the first end of the connecting rod along the direction of the connecting rod at the target historical moment can be determined through the angular relationship between the direction of the connecting rod and the movement direction of the connection point.

[0039] It is also possible to obtain images of the connecting rod in motion through multiple image acquisition devices to determine the position information of the connecting rod at different historical moments, and then determine the speed information of the two ends of the connecting rod at the target historical moment based on the position information of the connecting rod at different historical moments, so as to obtain the speed information of the two ends of the connecting rod along the direction of the connecting rod at the target historical moment.

[0040] Here, the image acquisition device can achieve adaptive compensation for the position or shooting angle of the image acquisition device based on the difference between the current position and the initial position, so as to avoid the adverse effects of possible jitter of the compressor on the captured image, which will not be elaborated here.

[0041] By means of a second speed sensor provided at the second end of the connecting rod, the second speed of the second end of the connecting rod along the direction of the connecting rod at the target historical moment can be obtained; the movement speed of the connection point between the crank pin and the connecting rod at the target historical moment can also be obtained through the speed sensor, and the second speed of the second end of the connecting rod along the direction of the connecting rod at the target historical moment can be determined through the angular relationship between the direction of the connecting rod and the movement direction of the connection point.

[0042] In this way, by obtaining the first speed and the second speed of the two ends of the connecting rod along the connecting rod direction, since the crank pin of the dynamically unbalanced crankshaft will generate additional centrifugal force, there is a difference between the first speed and the second speed. The absolute value of the difference between the first speed and the second speed is used as the speed difference value corresponding to the target historical moment, which helps to monitor the speed of the connecting rod so as to determine whether there is dynamic imbalance in the crankshaft.

[0043] In one embodiment, the magnitude of the angular acceleration of the center of the crank pin rotating around the axis of the crankshaft at the target historical moment is obtained in the following manner: obtaining the angular velocity information of the center of the crank pin along the axis of the crankshaft at the historical moment through a target sensor, and determining the magnitude of the angular acceleration of the center of the crank pin rotating around the axis of the crankshaft at the target historical moment based on the angular velocity information of the center of the crank pin along the axis of the crankshaft at multiple reference historical moments; wherein the reference historical moment is other historical moments adjacent to the target historical moment; and the target sensor includes at least one of an image sensor and an inertial measurement unit.

[0044] When the crankshaft rotating at a constant speed is in dynamic balance, the center of the crankpin rotates around the axis of the crankshaft at the same angular velocity at different times; when the crankshaft is in dynamic imbalance, the vibration amplitude or vibration frequency of the crankshaft will increase, causing the crankpin to generate additional centrifugal force.

[0045] Due to the additional centrifugal force of the crank pin, the angular velocity of the center of the crank pin rotating around the axis of the crankshaft changes, so that the angular velocity of the center of the crank pin rotating around the axis of the crankshaft at different times is different. There is a certain angular acceleration when the center of the crank pin rotates around the axis of the crankshaft at different times, and the magnitude of the angular acceleration at different times may be different.

[0046] By obtaining the angular velocity information of the center of the crank pin rotating around the axis of the crankshaft at different times, the angular acceleration information of the center of the crank pin rotating around the axis of the crankshaft at different times can be determined. For example, the angular velocity information of the center of the crank pin rotating around the axis of the crankshaft at different times can be curve fitted, and the fitted curve can be differentiated to obtain the angular acceleration information of the center of the crank pin rotating around the axis of the crankshaft at different times.

[0047] By setting an inertial measurement unit at the surface position of the crank pin at the center of the crank pin, the three-dimensional attitude angle and acceleration of the surface position can be measured, thereby obtaining the angular velocity of the center of the crank pin when it rotates, and obtaining the angular acceleration of the center of the crank pin at the target historical moment.

[0048] The image acquisition device installed inside the compressor can locate the center of the crank pin on the surface of the crank pin. The image acquisition device can also be provided with a corresponding inertial measurement unit to determine the position information of the image acquisition device itself.

[0049] The images captured by the image acquisition device can be used to determine the relative positional relationship between the image acquisition device and the surface position of the crank pin's center. Through the relative positional relationship and the position information of the image acquisition device itself, the positional information of the crank pin's center on the surface position of the crank pin can be determined.

[0050] By using the position information of the crankpin center on the crankpin surface at different times, the angular acceleration of the crankpin center rotating around the axis of the crankshaft at the target historical moment can be determined to determine whether the crankshaft in motion is in dynamic balance.

[0051] In this way, the angular acceleration of the center of the crank pin rotating around the axis of the crankshaft at the target historical moment can be determined by at least one of the image sensor and the inertial measurement unit, so as to determine whether the crankshaft in motion is unbalanced.

[0052] In step S102 , the confidence value of the crankpin at the target historical moment is determined based on the speed difference value and the angular acceleration magnitude within a preset time period before the target historical moment.

[0053] The confidence value is used to characterize the consistency of the changing direction of the velocity difference value and the angular acceleration magnitude within the preset time period; the larger the confidence value, the higher the consistency of the changing direction of the velocity difference value and the angular acceleration magnitude within the preset time period; conversely, the smaller the confidence value, the lower the consistency of the changing direction of the velocity difference value and the angular acceleration magnitude within the preset time period.

[0054] The greater the confidence value of the crankpin in motion at the target historical moment, the better the response stability among the crankpin, connecting rod, and crankshaft, or the more stable the connection among the crankpin, connecting rod, and crankshaft. When the crankshaft in motion is in an unbalanced state, the crankpin and connecting rod are more likely to have the same magnitude of imbalance, and the connection between the crankpin and connecting rod has a lower probability of aggravating the imbalance of the crankshaft.

[0055] Alternatively, if the confidence value of the crankpin at the target historical moment is higher, the probability of the crankshaft imbalance caused by the crankpin and the connecting rod is lower. If the crankshaft is unbalanced at this time, this unbalanced state of the crankshaft is more likely to be caused by the crankshaft itself, such as a deviation in the crankshaft axis or a deviation in the connection between the crankshaft and the crankpin. Therefore, by determining the confidence value of the crankpin at the target historical moment, it is helpful to more accurately determine whether the crankshaft is in a balanced state.

[0056] In one embodiment, determining the crankpin confidence value at the target historical moment based on the velocity difference value and the angular acceleration magnitude within a preset time period before the target historical moment includes: ,in, is the confidence value of the crankshaft at the target historical moment, arctan is the inverse tangent function, n is the number of historical moments in the preset time period, is the speed difference value at the jth historical moment in the preset time period, is the average value of the speed difference within the preset time period, is the standard deviation of the speed difference value within the preset time period, is the angular acceleration at the jth historical moment in the preset time period, is the average value of the angular acceleration within the preset time period, is the standard deviation of the angular acceleration within the preset time period.

[0057] By using the standard deviation of the speed difference value within the preset time period as the denominator, the speed difference value within the preset time period can be standardized. Since the units involved in the calculation in the numerator and denominator of the fraction containing the speed difference value are both speed, for example, the unit of speed is meters per second, the dimension of the speed difference value can be eliminated, which facilitates comparison of the direction of change of the speed difference value within the preset time period and the direction of change of the angular velocity within the preset time period.

[0058] The length of the preset time period can be set according to actual needs. For example, the length of the preset time period can be within 10 seconds to 20 seconds.

[0059] By using the standard deviation of the angular acceleration within a preset time period as the denominator, the angular acceleration within the preset time period can be standardized. Since the units involved in the calculation in the numerator and denominator of the fraction containing the angular acceleration are both angular acceleration, for example, the unit of angular acceleration is radians per second squared, the dimension of the angular acceleration can be eliminated, making it easier to compare the direction of change of the angular acceleration within the preset time period with the direction of change of the velocity difference value within the preset time period.

[0060] When the speed difference value at the historical moment is greater than the average of the speed difference values ​​in the preset time period, the difference between the speed difference value at the historical moment and the average of the speed difference values ​​in the preset time period is a positive number; if the angular acceleration at the historical moment is greater than the average of the angular acceleration in the preset time period, the difference between the angular acceleration at the historical moment and the average of the angular acceleration in the preset time period is a positive number, which means that the change directions of the speed difference value and the angular acceleration at the historical moment are the same. Through the calculation formula of the confidence value of the crankshaft at the target historical moment, the performance of the angular acceleration and the speed difference value in the preset time period can be comprehensively considered to determine the consistency of the change direction of the angular acceleration and the speed difference value.

[0061] π is the ratio of pi to the circumference of a circle. By combining pi with the inverse tangent function, the confidence value can be controlled between 0 and 1, as the value range of the inverse tangent function is between -π / 2 and π / 2. In combination with the existence of 1 / 2 in the calculation formula of the confidence value of the crank pin at the target historical moment, this facilitates comparison of different confidence values.

[0062] In this way, the more consistent the changing directions of the speed difference value and the angular acceleration magnitude within the preset time period are, the closer the confidence value is to 1; the less consistent the changing directions of the speed difference value and the angular acceleration magnitude within the preset time period are, the closer the confidence value is to 0. Therefore, the confidence value of the crank pin at the target historical moment can effectively characterize the consistency of the changing directions of the speed difference value and the angular acceleration magnitude within the preset time period.

[0063] In one embodiment, a confidence value of the crank pin at the target historical moment is determined based on the speed difference value and the angular acceleration magnitude within a preset time period before the target historical moment, including: normalizing the speed difference value within the preset time period before the target historical moment, and normalizing the angular acceleration magnitude within the preset time period before the target historical moment; determining the covariance between the normalized speed difference value and the normalized angular acceleration magnitude within the preset time period; and using the covariance as the confidence value of the crank pin at the target historical moment.

[0064] The speed difference values ​​within a preset time period before the target historical moment are normalized. The minimum-maximum normalization method can be used to control the speed difference values ​​after normalization within the range of 0 to 1 and avoid the influence of the dimension of the speed difference values ​​after normalization.

[0065] The angular acceleration within a preset time period before the target historical moment is normalized using a minimum-maximum normalization method. This method can not only control the angular acceleration after normalization within the range of 0 to 1, but also avoid the influence of the dimension of the angular acceleration after normalization, making it easier to compare the consistency of the change direction of the angular acceleration and the velocity difference value within the preset time period.

[0066] In this way, by determining the covariance between the normalized velocity difference value and the normalized angular acceleration magnitude within the preset time period, the consistency of the changing direction of the velocity difference value and the angular acceleration magnitude within the preset time period can be better determined; and since the velocity difference value and the angular acceleration magnitude for covariance calculation are normalized, the influence of the dimension of the parameter can also be avoided.

[0067] In step S103, based on the confidence value of the target historical moment, an imbalance value negatively correlated with the confidence value is determined.

[0068] In one embodiment, based on the confidence value of the target historical moment, an imbalance value that is negatively correlated with the confidence value is determined, including: determining the velocity difference value at the target historical moment and the multiplication value of the angular acceleration; and using the ratio of the multiplication value at the target historical moment to the confidence value at the target historical moment as the imbalance value at the target historical moment.

[0069] The larger the speed difference value or angular acceleration at the target historical moment, the greater the influence of the additional centrifugal force on the crankpin; the confidence value of the target historical moment is used to characterize the consistency of the changing direction of the speed difference value and the angular acceleration within the preset time period before the target historical moment; the larger the confidence value at the target historical moment, the more stable the connection between the crankpin and the connecting rod of the crankshaft, or at least the lower the probability of abnormality in the connection between the crankpin, connecting rod and piston.

[0070] The ratio of the product value at the target historical moment to the confidence value at the target historical moment is used as the imbalance value at the target historical moment. The obtained imbalance value can be used to characterize the probability that the crankshaft is unbalanced at the target historical moment, which facilitates comparison of the imbalance values ​​at different historical moments to determine whether the crankshaft has dynamic imbalance at the target historical moment.

[0071] In step S104, the imbalance values ​​of multiple historical moments are clustered to obtain multiple clusters, and the density value of the cluster to which the target historical moment belongs is determined. If the density value is less than a preset density threshold, a prompt message is output.

[0072] Since the imbalance value can reflect the operation status of the crankshaft, by clustering the imbalance values ​​at multiple historical moments to obtain multiple clusters, the operation status of the crankshaft at different historical moments can be compared.

[0073] Clustering of imbalance values ​​at multiple historical moments can be achieved by using clustering algorithms such as K-means clustering, hierarchical clustering, and density clustering.

[0074] The imbalance values ​​at multiple historical moments may be the imbalance values ​​of the crankshaft to be tested at multiple historical moments before the current moment, or may be the imbalance values ​​of other crankshafts other than the crankshaft to be tested at multiple historical moments before the current moment; the other crankshafts may be crankshafts that are completely consistent with the crankshaft to be tested in terms of model or length, etc. In order to more accurately determine whether the crankshaft to be tested has dynamic imbalance, the other crankshafts may be crankshafts that are in a dynamically balanced state.

[0075] Since the unbalanced state of the crankshaft is generated after a long period of use, or the unbalanced state of the crankshaft is a minority of the crankshafts in the produced crankshafts, when the imbalance values ​​at multiple historical moments are clustered to obtain multiple clusters, the crankshaft in the unbalanced state belongs to the cluster with the lowest degree of clustering among all the clusters.

[0076] In one embodiment, the density value of the cluster to which the imbalance value at the target historical moment belongs is obtained in the following manner: ,in, is the density value of the cluster to which the imbalance value at the target historical moment belongs, A is the number of imbalance values ​​in the cluster to which the imbalance value at the target historical moment belongs, It is the Euclidean distance between the ath imbalance value in the cluster to which the imbalance value at the target historical moment belongs and the center of the cluster.

[0077] In this way, the Euclidean distance between the imbalance value in the cluster to which the imbalance value at the target historical moment belongs and the center of the cluster is calculated. The larger the cumulative sum of the Euclidean distances, the lower the degree of aggregation of the cluster to which the imbalance value at the target historical moment belongs, and the more likely the crankshaft is in an unbalanced state at the target historical moment. Therefore, the determined density value can better characterize the probability that the crankshaft is in an unbalanced state at the target historical moment.

[0078] The prompt information is used to prompt that there is an abnormality in the crank pin at the target historical moment. The prompt information can be at least one of audio prompt information, text prompt information, vibration prompt information and light prompt information; for example, the prompt information can be displayed through a display device to prompt the user that the crankshaft has dynamic imbalance at the target historical moment, so as to facilitate the replacement of the crankshaft with dynamic imbalance; or, adjust the dynamically unbalanced crankshaft so that the adjusted crankshaft can achieve dynamic balance.

[0079] Through the crankshaft dynamic balance test data analysis method provided in the embodiment of the present application, the speed difference value of the first end and the second end of the connecting rod along the connecting rod direction at the target historical moment is obtained, and the angular acceleration of the center of the crank pin rotating around the axis of the crankshaft at the target historical moment is obtained, so as to determine the confidence value of the target historical moment. When the crankshaft is unbalanced in a moving state, the crankpin connected to the crankshaft will jitter, so that the speed difference value at both ends of the connecting rod and the angular acceleration of the crankpin may have abnormal values. By clustering the imbalance values ​​that are negatively correlated with the confidence values, the performance of the crankshaft at different times can be compared, and the balance abnormality of the crankshaft can be discovered in time.

[0080] Compared with using equipment to test the crankshaft alone, since the two parameter values ​​of speed difference and angular acceleration are obtained during the actual use of the crankshaft, they can better reflect the actual performance of the crankshaft when working in the compressor. Therefore, the balance test of the crankshaft can be achieved more accurately.

[0081] Figure 2 FIG. 1 is a structural diagram of a crankshaft dynamic balancing test data analysis system 1000 according to an exemplary embodiment. Figure 2 The crankshaft dynamic balancing test data analysis system 1000 includes: a processor 1100 and a memory 1200, wherein the memory 1200 stores computer program instructions, and when the computer program instructions are executed by the processor 1100, all or part of the steps of the crankshaft dynamic balancing test data analysis method in this application are implemented.

[0082] It should be understood that the features of some embodiments of the various applications described herein may be combined with each other unless specifically stated otherwise.

[0083] Although terms such as "first," "second," and "third" may be used herein to describe various components, parts, regions, layers, or sections, these components, parts, regions, layers, or sections are not limited to these terms. Rather, these terms are used only to distinguish one component, part, region, layer, or section from another component, part, region, layer, or section. Therefore, without departing from the teachings of the examples described herein, a first component, part, region, layer, or section mentioned in the examples may also be referred to as a second component, part, region, layer, or section.

[0084] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In this description, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0085] Furthermore, the word "exemplary" is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as advantageous over other aspects or designs. Rather, the use of the word exemplary is intended to present concepts in a concrete manner. As used herein, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or."

[0086] Likewise, although the present application has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art upon reading and understanding this specification and the accompanying drawings. With particular regard to the various functions performed by the components (e.g., elements, resources, etc.) described above, unless otherwise indicated, the terms used to describe such components are intended to correspond to any component (functionally equivalent) that performs the specific functions of the described components, even if not structurally equivalent to the disclosed structures.

[0087] Additionally, while particular features of the present application may have been disclosed with respect to only one of several implementations, such features may be combined with one or more other features of other implementations as may be desired and advantageous for any given or particular application.

[0088] Those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein, and the description and examples are to be considered merely as exemplary.

[0089] It will be understood that the present application is not limited to the exact construction that has been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof.

Claims

1. A method for analyzing crankshaft dynamic balancing test data, wherein the crank pin of the crankshaft is connected to the first end of the connecting rod, and the second end of the connecting rod is connected to the piston, characterized in that: The method comprises: For a target historical moment among the multiple historical moments, obtain a speed difference value of the first end and the second end of the connecting rod along the connecting rod direction at the target historical moment, and obtain an angular acceleration magnitude of the center of the crank pin rotating around the axis of the crankshaft at the target historical moment; Determine the confidence value of the crank pin at the target historical moment according to the speed difference value and the angular acceleration magnitude in a preset time period before the target historical moment; the confidence value is used to characterize the consistency of the change direction of the speed difference value and the angular acceleration magnitude in the preset time period; According to the confidence value of the target historical moment, determine the imbalance value that is negatively correlated with the confidence value; The imbalance values ​​at multiple historical moments are clustered to obtain multiple clusters, and the density value of the cluster to which the imbalance value at the target historical moment belongs is determined. When the density value is less than a preset density threshold, a prompt message is output; the prompt message is used to prompt that the crank pin is abnormal at the target historical moment.

2. The crankshaft dynamic balancing test data analysis method according to claim 1, characterized in that: According to the speed difference value and the angular acceleration value in a preset time period before the target historical moment, the confidence value of the crank pin at the target historical moment is determined, including: ,in, is the confidence value of the crankshaft at the target historical moment, arctan is the inverse tangent function, n is the number of historical moments in the preset time period, is the speed difference value at the jth historical moment in the preset time period, is the average value of the speed difference within the preset time period, is the standard deviation of the speed difference value within the preset time period, is the angular acceleration at the jth historical moment in the preset time period, is the average value of the angular acceleration within the preset time period, is the standard deviation of the angular acceleration within the preset time period.

3. The crankshaft dynamic balancing test data analysis method according to claim 1, characterized in that: According to the speed difference value and the angular acceleration value in a preset time period before the target historical moment, the confidence value of the crank pin at the target historical moment is determined, including: Normalizing the velocity difference value within a preset time period before the target historical moment, and normalizing the angular acceleration magnitude within a preset time period before the target historical moment; Determine the covariance between the normalized velocity difference value and the normalized angular acceleration magnitude within a preset time period; The covariance is used as the confidence value of the crank pin at the target historical moment.

4. The crankshaft dynamic balancing test data analysis method according to claim 1, characterized in that: According to the confidence value of the target historical moment, determine the imbalance value that is negatively correlated with the confidence value, including: Determine the velocity difference value of the target at the historical moment and the multiplication value of the angular acceleration; The ratio of the multiplication value of the target historical moment to the confidence value of the target historical moment is used as the imbalance value of the target historical moment.

5. The crankshaft dynamic balancing test data analysis method according to claim 1, characterized in that: The density value of the cluster to which the imbalance value at the target historical moment belongs is obtained in the following way: ,in, is the density value of the cluster to which the imbalance value at the target historical moment belongs, A is the number of imbalance values ​​in the cluster to which the imbalance value at the target historical moment belongs, It is the Euclidean distance between the ath imbalance value in the cluster to which the imbalance value at the target historical moment belongs and the center of the cluster.

6. The crankshaft dynamic balancing test data analysis method according to claim 1, characterized in that: The velocity difference between the first end and the second end of the connecting rod along the connecting rod direction at the target historical moment is obtained by the following method: Obtaining a first speed sensor disposed at the first end of the connecting rod, a first speed of the first end of the connecting rod along the connecting rod direction at a target historical moment; Acquire a second speed of the second end of the connecting rod along the connecting rod direction at the target historical moment through a second speed sensor arranged at the second end of the connecting rod; The absolute value of the difference between the first speed and the second speed along the connecting rod direction at the target historical moment is used as the speed difference value corresponding to the target historical moment.

7. The crankshaft dynamic balancing test data analysis method according to claim 1, characterized in that: The angular acceleration of the center of the crank pin rotating around the axis of the crankshaft at the target historical moment is obtained by: The angular velocity information of the center of the crank pin along the axis of the crankshaft at a historical moment is obtained through a target sensor, and the magnitude of the angular acceleration of the center of the crank pin rotating around the axis of the crankshaft at a target historical moment is determined according to the angular velocity information of the center of the crank pin along the axis of the crankshaft at multiple reference historical moments; The reference historical moment is other historical moments adjacent to the target historical moment; the target sensor includes at least one of an image sensor and an inertial measurement unit.

8. A crankshaft dynamic balance test data analysis system, characterized in that: include: A processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the crankshaft dynamic balancing test data analysis method according to any one of claims 1-7 is implemented.

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