Servo system life test method, device, computer equipment and storage medium

Abstract

The present application relates to a servo system life test method, device, computer equipment and storage medium, the method includes: obtaining servo system parameters and preset load conditions for servo system life test; the load size under the preset load conditions is greater than the corresponding load size under rated working conditions; the preset load conditions include the axial force and radial force load conditions of the servo motor, and the temperature load conditions of the servo drive; according to the axial force load conditions, radial force load conditions, temperature load conditions and servo system parameters, the servo system acceleration factor is calculated; according to the servo system parameters and the servo system acceleration factor, the accelerated life test time is determined; output life test start instructions; the life test start instructions are used to instruct the user to apply the preset load conditions to the servo system to be tested within the accelerated life test time to perform a servo system life test. The above-mentioned servo system life test method can reduce the time cost of the servo system life test.

Description

Technical Field

[0001] The present application relates to the technical field of reliability evaluation, and in particular to a servo system life test method, device, computer equipment and storage medium. Background Art

[0002] The servo system, also known as the follow-up system, refers to an automatic control system that uses the function of a certain component to make the state of the system reach or approach a predetermined value, and can compare the desired state with the actual state, and adjust the control component according to their difference. The servo system has many advantages such as high precision, high stability and strong adaptability. It is widely used in national defense, military industry, automatic driving, automatic machine tools, wireless tracking control and other fields. In order to ensure the reliability of the servo system, it is necessary to conduct a life test on the servo system.

[0003] The traditional servo system life test method is to conduct the test under the load conditions corresponding to the use environment. However, the reliability index of the servo system often reaches tens of thousands of hours, and the traditional reliability test requires a lot of time and money. Therefore, the traditional servo system life test method has the disadvantage of high time cost. Summary of the invention

[0004] Based on this, it is necessary to provide a servo system life test method, device, computer equipment and storage medium to address the above technical problems, so as to reduce the time cost of the servo system life test.

[0005] A servo system life test method, comprising:

[0006] Acquire servo system parameters and preset load conditions for servo system life test; the load magnitude under the preset load conditions is greater than the corresponding load magnitude under rated working conditions; the preset load conditions include axial force load conditions and radial force load conditions of the servo motor, and temperature load conditions of the servo drive;

[0007] Calculating a servo system acceleration factor according to the axial force load condition, the radial force load condition, the temperature load condition and the servo system parameter;

[0008] Determining an accelerated life test time according to the servo system parameters and the servo system acceleration factor;

[0009] Output a life test start instruction; the life test start instruction is used to instruct the user to apply the preset load condition to the servo system to be tested within the accelerated life test time to perform a servo system life test.

[0010] In one embodiment, the calculating of the servo system acceleration factor according to the axial force load condition, the radial force load condition, the temperature load condition and the servo system parameter comprises:

[0011] Calculating a servo motor acceleration factor according to the axial force load condition and the radial force load condition, and the servo system parameters;

[0012] Calculating a servo drive acceleration factor according to the temperature load condition and the servo system parameters;

[0013] A servo system acceleration factor is determined according to the servo motor acceleration factor and the servo driver acceleration factor.

[0014] In one embodiment, the servo system parameters include servo motor operating parameters and bearing parameters on the servo motor; the servo motor acceleration factor is calculated according to the axial force load condition, the radial force load condition, and the servo system parameters, including:

[0015] Obtaining a reference life of the servo motor under rated working conditions according to the servo motor operating parameters and the bearing parameters;

[0016] According to the servo motor operating parameters and the bearing parameters, as well as the axial force load condition and the radial force load condition, the accelerated life of the servo motor under the preset load condition is obtained;

[0017] The servo motor acceleration factor is calculated according to the reference life and the accelerated life.

[0018] In one embodiment, obtaining the reference life of the servo motor under rated working conditions according to the servo motor operating parameters and the bearing parameters includes:

[0019] According to the bearing parameters, the equivalent dynamic load of the corresponding bearing under rated working conditions is calculated;

[0020] The reference life of the servo motor under rated working conditions is obtained according to the servo motor operating parameters, the bearing parameters and the equivalent dynamic load.

[0021] In one embodiment, the servo system parameters include component composition and operating parameters of the servo drive; and calculating the servo drive acceleration factor according to the temperature load condition and the servo system parameters includes:

[0022] Calculating the failure rate of each component under rated working conditions according to the component composition and operating parameters of the servo drive;

[0023] Calculating the acceleration factor of each component according to the component composition and operating parameters of the servo drive and the temperature load conditions;

[0024] The servo drive acceleration factor is calculated according to the failure rate and acceleration factor of each component.

[0025] In one embodiment, the calculating the acceleration factor of each component according to the component composition and operating parameters of the servo drive and the temperature load condition includes:

[0026] Determining the activation energy of each component according to the component composition of the servo drive and the corresponding relationship between the component type and the activation energy;

[0027] The acceleration factor of each component is calculated according to the activation energy of each component, as well as the temperature load condition and working parameters of the servo drive.

[0028] In one embodiment, the servo system parameters include the number of servo systems put into life test, the mean time between failures under rated conditions, and the type of reliability test statistical scheme; determining the accelerated life test time according to the servo system parameters and the servo system acceleration factor includes:

[0029] Determine the reference life test time of the servo system according to the mean trouble-free working time under the rated working condition and the type of the reliability test statistical scheme;

[0030] The accelerated life test time is determined according to the reference life test time, the number of servo systems and the servo system acceleration factor.

[0031] A servo system life test device, comprising:

[0032] An acquisition module is used to acquire servo system parameters and preset load conditions for a servo system life test; the load value under the preset load condition is greater than the corresponding load value under the rated working condition; the preset load condition includes the axial force load condition and radial force load condition of the servo motor, and the temperature load condition of the servo drive;

[0033] an acceleration factor calculation module, used to calculate the servo system acceleration factor according to the axial force load condition, the radial force load condition, the temperature load condition and the servo system parameters;

[0034] An accelerated life test time determination module, used to determine the accelerated life test time according to the servo system parameters and the servo system acceleration factor;

[0035] The output module is used to output a life test start instruction; the life test start instruction is used to instruct the user to apply the preset load condition to the servo system to be tested within the accelerated life test time to perform a servo system life test.

[0036] In one embodiment, the acceleration factor calculation module includes: a servo motor acceleration factor calculation unit, which is used to calculate the servo motor acceleration factor based on the axial force load condition and the radial force load condition, as well as the servo system parameters; a servo drive acceleration factor calculation unit, which is used to calculate the servo drive acceleration factor based on the temperature load condition and the servo system parameters; and an acceleration factor determination unit, which is used to determine the servo system acceleration factor based on the servo motor acceleration factor and the servo drive acceleration factor.

[0037] In one embodiment, the servo system parameters include the servo motor operating parameters and the bearing parameters on the servo motor; the servo motor acceleration factor calculation unit includes: a baseline life calculation component, which is used to obtain the baseline life of the servo motor under rated conditions based on the servo motor operating parameters and the bearing parameters; an accelerated life calculation component, which is used to obtain the accelerated life of the servo motor under preset load conditions based on the servo motor operating parameters and the bearing parameters, as well as the axial force load conditions and the radial force load conditions; and a servo motor acceleration factor calculation component, which is used to calculate the servo motor acceleration factor based on the baseline life and the accelerated life.

[0038] In one embodiment, the reference life calculation component is specifically used to: calculate the equivalent dynamic load of the corresponding bearing under rated conditions based on the bearing parameters; and obtain the reference life of the servo motor under rated conditions based on the servo motor working parameters, bearing parameters and equivalent dynamic load.

[0039] In one of the embodiments, the servo system parameters include the component composition and operating parameters of the servo drive; the servo drive acceleration factor calculation unit includes: a component failure rate calculation component, which calculates the failure rate of each component under rated working conditions according to the component composition and operating parameters of the servo drive; a component acceleration factor calculation component, which calculates the acceleration factor of each component according to the component composition and operating parameters of the servo drive and temperature load conditions; and a servo drive acceleration factor calculation component, which calculates the servo drive acceleration factor according to the failure rate and acceleration factor of each component.

[0040] In one of the embodiments, the component acceleration factor calculation component is specifically used to: determine the activation energy of each component based on the component composition of the servo drive and the correspondence between the component type and the activation energy; calculate the acceleration factor of each component based on the activation energy of each component and the temperature load conditions and operating parameters of the servo drive.

[0041] In one embodiment, the servo system parameters include the number of servo systems put into life test, the mean time between failures under rated conditions and the type of reliability test statistical scheme; the accelerated life test time determination module includes: a benchmark life test time determination unit, used to determine the benchmark life test time of the servo system based on the mean time between failures under rated conditions and the type of reliability test statistical scheme; an accelerated life test time determination unit, used to determine the accelerated life test time based on the benchmark life test time, the number of servo systems and the servo system acceleration factor.

[0042] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0043] A computer-readable storage medium stores a computer program, which implements the steps of the above method when executed by a processor.

[0044] The above-mentioned servo system life test method uses a load condition that is greater than the corresponding load size under the rated working condition to conduct the servo system life test, which is equivalent to an accelerated test under accelerated stress conditions. It can shorten the life test time, reduce the time cost of the servo system life test, and is conducive to improving the test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a flow chart of a servo system life test method in one embodiment;

[0046] Figure 2 is a flow chart of calculating the servo system acceleration factor according to the axial force load condition, the radial force load condition and the servo system parameters in one embodiment;

[0047] Figure 3 is a flow chart for calculating the servo motor acceleration factor according to the axial force load condition and the radial force load condition, as well as the servo system parameters in one embodiment;

[0048] Figure 4 A flowchart of calculating the reference life of the servo motor under rated working conditions according to the servo motor working parameters and bearing parameters in one embodiment;

[0049] Figure 5 is a flow chart for calculating the servo drive acceleration factor according to temperature load conditions and servo system parameters in one embodiment;

[0050] Figure 6 It is a flow chart of calculating the acceleration factor of each component according to the component composition and working parameters of the servo drive and the temperature load conditions in one embodiment;

[0051] Figure 7 is a flow chart of determining the accelerated life test time according to the servo system parameters and the servo system acceleration factor in one embodiment;

[0052] Figure 8 is a structural block diagram of a servo system life test device in one embodiment;

[0053] Fig. 9 is a structural block diagram of an acceleration factor calculation module in an embodiment;

[0054] Fig.10 is a structural block diagram of a servo motor acceleration factor calculation unit in one embodiment;

[0055] Fig.11 is a structural block diagram of a servo drive acceleration factor calculation unit in an embodiment;

[0056] Fig.12 It is a structural block diagram of an accelerated life test time determination module in one embodiment;

[0057] Fig.13 1 is a structural block diagram of a computer device in one embodiment. DETAILED DESCRIPTION

[0058] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0060] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element, or connected to the other element through an intermediate element. In addition, the "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if there is transmission of electrical signals or data between the connected objects.

[0061] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof.

[0062] The servo system is a typical electromechanical system, including a servo motor and a servo drive. The servo motor is a mechanical component, and the servo drive is an electronic component. Different components have different sensitive stresses and acceleration models, so it is particularly important to establish a comprehensive life test method for the servo system. Based on this, in the first aspect of this application, Figure 1 As shown, a servo system life test method is provided, including steps S200 to S800.

[0063] Step S200: Acquire servo system parameters and preset load conditions for a servo system life test; the preset load conditions include axial force load conditions and radial force load conditions of the servo motor, and temperature load conditions of the servo drive.

[0064] The servo system parameters include structural parameters, operating parameters and test parameters. The structural parameters include the specific composition of the servo system, the dimensions of each component, the installation method and materials, etc. The operating parameters include the application scenario and the motor speed, torque load preset value and reference operating temperature under the application scenario. The test parameters include the number of servo systems put into life testing, the average trouble-free working time under rated conditions and the type of reliability test statistical scheme, etc.

[0065] Furthermore, the preset load conditions of the servo system life test refer to the load type, load size and loading position planned to be applied to the servo system to be tested. Specifically, the preset load conditions include the axial force load conditions and radial force load conditions of the servo motor, as well as the temperature load conditions of the servo drive, and the load size under the preset load conditions is greater than the corresponding load size under the rated working conditions. In other words, the load size under the axial force load conditions and radial force load conditions of the servo motor is respectively greater than the allowable axial force load and allowable radial force load under the rated working conditions of the corresponding servo motor. The temperature load size of the servo drive is greater than the temperature load value of the servo drive under the rated working conditions.

[0066] In addition, the controller may obtain the preset load conditions and servo system parameters of the servo system life test in an active manner or in a passive manner.

[0067] Step S400: Calculate the servo system acceleration factor according to the axial force load condition, the radial force load condition, the temperature load condition and the servo system parameters.

[0068] As mentioned above, the load size under the preset load condition is greater than the corresponding load size under the rated working condition, which is equivalent to the accelerated life test under accelerated stress. Correspondingly, the acceleration factor refers to the ratio of a certain life characteristic value of the product under accelerated stress to the life characteristic value under normal stress, which can also be called the acceleration coefficient, which is a dimensionless number. The acceleration factor reflects the acceleration effect of a certain accelerated stress level in the accelerated life test and is a function of the accelerated stress.

[0069] Specifically, according to the servo system parameters and preset load conditions such as axial force load conditions, radial force load conditions, and temperature load conditions, the stress conditions of each component of the servo system under the preset load conditions can be determined, and the weakest component of the servo system, such as a bearing or a circuit component, can be obtained. Then, the stress analysis is performed on the weakest component, and the acceleration factor of the weakest component under the preset load conditions is calculated, which is the servo system acceleration factor.

[0070] It should be noted that the preset load conditions of the servo system life test can be constant or can change according to a certain rule, such as step changes. For constant load conditions, the servo system acceleration factor is a fixed value, and for variable load conditions, the servo system acceleration factor will also change accordingly, but the corresponding relationship between the servo system acceleration factor and the load conditions is fixed.

[0071] Step S600: Determine the accelerated life test time according to the servo system parameters and the servo system acceleration factor.

[0072] The accelerated life test time refers to the life test time of the servo system under preset load conditions. Specifically, according to the servo system parameters, the benchmark life test time of the servo system under rated conditions can be determined, and then combined with the number of servo systems put into life test and the servo system acceleration factor, the accelerated life test time of the accelerated life test can be determined.

[0073] Step S800: outputting a life test start instruction; the life test start instruction is used to instruct the user to apply a preset load condition to the servo system to be tested within the accelerated life test time to perform a servo system life test.

[0074] Among them, the life test start instruction includes a preset load condition and an accelerated life test time. Specifically, the output object of the life test start instruction can be a display or a terminal. The user can obtain the specific information of the life test start instruction through the display or the terminal, so that the preset load condition is applied to the servo system to be tested within the accelerated life test time to perform a servo system life test. After the life test is completed, the controller obtains the key performance indicators of the servo system, and judges whether the servo system fails based on the key performance indicators and the preset failure conditions, and obtains the life test result of whether the servo system passes the test. The key performance indicators include but are not limited to the speed, torque, power of the servo system under test and the current and voltage of its driver. The standard for judging whether the servo system fails can be to compare the key collected value with the set value, and when the collected value does not reach the corresponding set value, the servo system is judged to be failed; the collected value of the key performance indicator can also be compared with the collected value of the corresponding indicator before the test, and when the change amount of the key performance indicator reaches the corresponding preset value, the servo system is judged to be failed.

[0075] The above-mentioned servo system life test method uses a load condition that is greater than the corresponding load size under the rated working condition to conduct the servo system life test, which is equivalent to an accelerated test under accelerated stress conditions. It can shorten the life test time, reduce the time cost of the servo system life test, and is conducive to improving the test efficiency.

[0076] In one embodiment, Figure 2 As shown, step S400 includes steps S420 to S460.

[0077] Step S420: Calculate the servo motor acceleration factor according to the axial force load condition and the radial force load condition, as well as the servo system parameters.

[0078] Among them, axial refers to the direction along the axis of the shaft, and radial refers to the direction along the radius of the shaft. Specifically, the axial force load conditions and radial force load conditions of the servo motor include the magnitude, direction and loading position of the axial force load, and the magnitude, direction and loading position of the radial force load. Furthermore, the load loading position is the same as the load loading position and direction under the rated working condition, that is, the preset load condition of the servo motor is a numerical increase in the load magnitude compared to the corresponding load condition under the rated working condition.

[0079] Specifically, on the one hand, according to the system parameters of the servo motor, the load conditions under the rated working conditions of the servo motor can be obtained, and then the relationship between the preset load conditions and the rated working load conditions of the servo motor can be obtained. On the other hand, according to the stress conditions of each component of the servo motor under the preset load conditions, the weakest component of the servo motor can be obtained. Finally, the stress analysis of the weakest component is carried out, and the acceleration factor of the servo motor can be calculated by combining the relationship between the preset load conditions and the rated working load conditions, as well as the life model of the servo motor under axial force and radial force loads.

[0080] Step S440: Calculate the servo drive acceleration factor according to the temperature load condition and the servo system parameters.

[0081] As mentioned above, the servo drive is an electronic component, and its sensitive stress is temperature stress. Therefore, the preset load condition of the servo drive is set to a temperature load condition, specifically a preset test temperature. The preset test temperature is higher than the reference operating temperature of the servo drive under rated working conditions.

[0082] Specifically, the servo drive acceleration factor can be calculated based on a series model or a parallel model, or it can be calculated based on the barrel effect. Taking the barrel effect as an example, on the one hand, based on the system parameters of the servo drive, the reference operating temperature of the servo drive under rated conditions can be obtained, and then the relationship between the preset load conditions and the rated operating load conditions of the servo drive can be determined. On the other hand, based on the material properties of each component of the servo drive, the life of each component under the preset load conditions can be calculated, and then the weakest component of the servo drive can be determined. Finally, for the weakest component, combined with the relationship between the preset load conditions and the rated operating load conditions, as well as the life model of the servo drive under temperature load conditions, the servo drive acceleration factor can be calculated.

[0083] Step S460: Determine the servo system acceleration factor according to the servo motor acceleration factor and the servo driver acceleration factor.

[0084] Specifically, there is no unique way to determine the servo system acceleration factor. For example, the larger value of the servo motor acceleration factor and the servo driver acceleration factor can be taken as the servo system acceleration factor; or corresponding weights can be set according to the sensitivity of the servo motor and servo driver in the life test, and the servo motor acceleration factor and the servo driver acceleration factor are multiplied by their respective weights and then added to obtain the servo system acceleration factor.

[0085] In one embodiment, the life distribution functions of the servo motor and the servo driver both obey exponential distribution, and step S460 includes: determining the servo motor acceleration factor or the servo driver acceleration factor as the servo system acceleration factor.

[0086] Specifically, when the life distribution functions of the servo motor and servo drive both obey exponential distribution, the calculation formula for the mean time between failures (MTBF) of the two is:

[0087]

[0088] Then the servo system acceleration factor AF is:

[0089]

[0090] Where t0 is the life of the servo system under rated conditions, t is the life of the servo system under preset load conditions, and λ 总0 is the failure rate of the servo system under rated conditions; λ1 is the failure rate of the servo motor under rated conditions; λ2 is the failure rate of the servo drive under rated conditions; λ' 总 is the failure rate of the servo system under the preset load condition; λ'1 is the failure rate of the servo motor under the preset load condition; λ'2 is the failure rate of the servo drive under the preset load condition.

[0091] Furthermore, in order to facilitate the determination of the acceleration factor of the servo system, we can set the acceleration factors of the servo motor and the servo drive to be equal. Assume that the servo motor and the servo drive are in series and their acceleration factors are equal. Also, because the failure rates of the servo motor and the servo drive follow an exponential distribution, that is:

[0092]

[0093] Combining equation (2) and equation (3), we can get:

[0094] AF=AF l =AF2 (4)

[0095] That is, the servo motor acceleration factor, the servo driver acceleration factor and the servo system acceleration factor are equal. After the servo motor acceleration factor and the servo driver acceleration factor are calculated, the servo motor acceleration factor or the servo driver acceleration factor can be determined as the servo system acceleration factor.

[0096] It can be understood that in other embodiments, it is possible to first determine whether the life distribution functions of the servo motor and the servo drive both obey the exponential distribution. If so, execute step S420 or step S440, and determine the servo system acceleration factor based on the corresponding calculation results; if not, execute step S420 and step S440, and then determine the servo system acceleration factor based on the corresponding calculation results.

[0097] In the above embodiment, a specific calculation method for the servo system acceleration factor is given. The servo system acceleration factor is determined by comprehensively considering the factors of the servo motor and the servo driver, which is beneficial to improving the accuracy of the servo system acceleration factor and further enhancing the credibility of the servo system life test method.

[0098] In one embodiment, the servo system parameters include servo motor operating parameters and bearing parameters on the servo motor. Figure 3 As shown, step S420 includes steps S422 to S426.

[0099] Step S422: Obtain the reference life of the servo motor under rated working conditions according to the servo motor operating parameters and bearing parameters.

[0100] The bearing parameters on the servo motor include the type, specification, installation position and stiffness of the bearing. Specifically, under the action of axial force and radial force, after analysis, it is not difficult to conclude that the weakest component of the servo motor is the deep groove ball bearing, including the front deep groove ball bearing and the rear deep groove ball bearing. According to the operating parameters of the servo motor and the corresponding parameters of the deep groove ball bearing, the benchmark life of the servo motor under rated conditions can be obtained.

[0101] In one embodiment, Figure 4 As shown, step S422 includes step S422-1 and step S422-2.

[0102] Step S422-1: Calculate the equivalent dynamic load of the corresponding bearing under rated working conditions according to the bearing parameters.

[0103] The equivalent dynamic load is a load with a constant direction and magnitude. Under this load, the bearing has the same life as under actual load conditions.

[0104] Specifically, under rated conditions, the servo motor is subjected to 1 times the allowable radial force load F r0 and 1 times the allowable axial force load F a0 Considering the servo motor bearing preload and the motor structure, it can be seen that the front bearing is subjected to the spring preload axially, which is related to F a0 In the same direction; the rear bearing axially bears the reaction force of the rear bearing seat support, and F a0 Reverse direction. Based on the force and torque balance of the motor shaft under the action of external load, the axial load and radial load of the front and rear bearings can be calculated.

[0105] F aO +F al =F a2 (5)

[0106]

[0107]

[0108] In the formula, F a1 is the axial load on the front bearing, which is related to F a0 Same direction; F a2 is the axial load on the rear bearing, which is related to F a0 Reverse; F r1 is the radial load on the front bearing, which is related to F r0 Reverse; F r2 is the radial load on the rear bearing, which is related to F r0 Same direction; is the distance between the front and rear bearings; is the distance between the external load loading position and the front bearing; It is the distance between the external load loading position and the rear bearing.

[0109] Under external load, the axial displacements of the two bearings are equal (equivalent to two springs in parallel), and we can get:

[0110]

[0111] Where k1 and k2 are the axial stiffness of the front and rear bearings, respectively, which can be obtained according to equations (9)-(11).

[0112]

[0113]

[0114]

[0115] Among them, D W is the bearing roller diameter, Z is the number of bearing rollers, α is the initial contact angle, u r is the radial clearance, q is the curvature center distance parameter, F ai is the axial load on the corresponding bearing.

[0116] Combining equations (5)-(11), the axial load and longitudinal load on the front and rear bearings under rated conditions can be obtained, that is, F a1 、F a2 、F r1 and F r2 Then the equivalent dynamic load P i The calculation formula is:

[0117] P i =XF ri +YF ai (12)

[0118] Where P iis the equivalent dynamic load; X is the radial dynamic load coefficient; Y is the axial dynamic load coefficient. The load coefficients X and Y can be determined by referring to the table in the "Mechanical Design Manual" (6th edition, edited by Cheng Daxian) based on the size and performance of the deep groove ball bearing, including: according to GB / T 4662, the calculation coefficient f0 is obtained; according to the size of the deep groove ball bearing, the basic rated load C is determined 0r , and then calculate f0F ai / C 0r , determine the coefficient e according to the calculation results; finally compare F ai / F ri Based on the relationship between the magnitude of and e, determine the load factors X and Y by looking up the table.

[0119] Specifically, F a1 and F r1 Substituting into equation (12), the equivalent dynamic load P1 of the front bearing can be obtained. a2 and F a2 Substituting into equation (12), the equivalent dynamic load P2 of the rear bearing can be obtained. The larger value is selected by comparison as the equivalent dynamic load P0 of the entire servo motor.

[0120] Step S422-2: Obtain the reference life of the servo motor under rated working conditions according to the servo motor operating parameters, bearing parameters and equivalent dynamic load.

[0121] As mentioned above, the servo motor operating parameters include the application scenario and the motor speed, torque load preset value and reference operating temperature in the application scenario. Specifically, the impact load factor can be determined based on the application scenario of the servo motor and the correspondence between the pre-stored application scenario and the load property; the torque load can be obtained according to equations (6) and (7), and then combined with the torque load preset value, the magnitude relationship between the current torque load and the torque load preset value can be obtained to determine the torque load factor; the speed factor can be determined based on the motor speed in the specific application scenario and the pre-stored correspondence between the motor speed and the speed factor; the temperature factor can be determined based on the reference operating temperature in the specific application scenario and the pre-stored correspondence between the reference operating temperature and the temperature factor; the basic rated load can be determined based on the size of the deep groove ball bearing. Combined with the equivalent dynamic load of the servo motor, the reference life t of the servo motor under rated conditions can be obtained. 10 , the specific formula is:

[0122]

[0123] In the formula, f n is the velocity factor, f T is the temperature factor, f d is the impact load factor; f mis the torque load factor, which takes the value of 2 when the current torque load is greater than or equal to the preset torque load value, otherwise takes the value of 1.5. ε is the life index, and for servo motor ball bearings, ε=3.

[0124] Step S424: Obtain the accelerated life of the servo motor under preset load conditions according to the servo motor operating parameters and bearing parameters, as well as the axial force load conditions and the radial force load conditions.

[0125] The specific calculation process of the accelerated life is the same as the calculation process of the reference life. It is only necessary to change the external load condition from the rated working condition to the preset load condition and repeat the analysis and calculation process in step S422.

[0126] Step S426: Calculate the servo motor acceleration factor according to the reference life and the accelerated life.

[0127] Specifically, the servo motor acceleration factor AF1 is the reference life t 10 The ratio of the accelerated life t1 is:

[0128]

[0129] Furthermore, considering that in the calculation process of the reference life and the accelerated life, the speed factor f n , temperature factor f T , impact load factor f d ; Life index ε and basic rated load C 0r are the same, formula (14) can be expressed as:

[0130]

[0131] Where f' m is the moment load factor under the preset loading conditions, f m is the torque load factor under rated working conditions, and P is the equivalent dynamic load of the entire servo motor under preset load conditions. That is, according to the preset load conditions and the external load under rated working conditions, the torque load under preset load conditions and rated working conditions can be obtained according to equations (6) and (7) respectively, and f' is obtained. m and f m Then, according to the bearing parameters, the equivalent dynamic load of the corresponding bearing under the preset load conditions and the rated working conditions is calculated respectively to obtain the ratio of P and P0. The servo motor acceleration factor AF1 can be calculated according to formula (15).

[0132] Understandably, when f' m and f m When they are equal, formula (15) can be further simplified as:

[0133]

[0134] That is, according to the preset load condition and the external load under the rated working condition, the moment load under the preset load condition and the rated working condition can be obtained by using the root formula (6) and (7) respectively, and the value of f' can be determined. m and f m If they are not equal, according to f' m and f m The ratio of and formula (15) are used to calculate the servo motor acceleration factor AF1; when the two are equal, just substitute P and P0 into formula (16) to calculate the servo motor acceleration factor AF1.

[0135] In the above embodiment, a specific calculation process of the servo motor acceleration factor is given. During the calculation process, the servo motor structure and working parameters, as well as the external load conditions it is subjected to are fully considered, which is conducive to improving the accuracy of the acceleration factor and further enhancing the credibility of the life test method.

[0136] In one embodiment, the servo system parameters include the component composition and operating parameters of the servo drive; Figure 5 As shown, step S440 includes steps S442 to S446.

[0137] Step S442: Calculate the failure rate of each component under rated working conditions according to the component composition of the servo drive.

[0138] Among them, the working parameters of the servo drive include the type and magnitude of stress to which the servo drive is subjected under rated conditions. Since the servo drive is an electronic component and is sensitive to temperature, the failure rate is calculated based on the temperature stress under rated conditions. Specifically, based on the component composition of the servo drive and the temperature stress conditions under rated conditions, the stress analysis method provided by GJB299C is used to calculate the failure rate of each component under rated conditions. Furthermore, based on the sensitivity of electronic components to temperature, certain specific components in the servo drive can be defined as sensitive components, and only the failure rates of these components under rated conditions are calculated to reduce the computational workload and improve efficiency.

[0139] Step S444: Calculate the acceleration factor of each component according to the component composition and operating parameters of the servo drive and the temperature load conditions.

[0140] The operating parameters of the servo drive include the reference operating temperature of the servo drive under rated working conditions. Specifically, according to the operating parameters of the servo drive, the preset test temperature of the servo drive under preset load conditions and the reference operating temperature under rated working load conditions can be determined. Then, according to the characteristics of each component and the relationship between the preset test temperature and the reference operating temperature, the acceleration factor of each component can be calculated.

[0141] In one embodiment, Figure 6 As shown, step S444 includes step S444-1 and step S444-2.

[0142] Step S444-1: Determine the activation energy of each component according to the component composition of the servo drive and the correspondence between the component type and the activation energy.

[0143] Specifically, the correspondence between component types and activation energies can be pre-stored according to standards such as IEC61709, IEC62380, IPC279, GJB299C, component test values, and related literature. The controller obtains the component types that need to be analyzed for life according to the component composition of the servo drive, and then determines the activation energy of each component based on the correspondence between component types and activation energies.

[0144] Step S444-2: Calculate the acceleration factor of each component according to the activation energy of each component, as well as the temperature load conditions and operating parameters of the servo drive.

[0145] Specifically, the Arrhenius temperature stress model is used to evaluate the acceleration factor of each component in the servo system:

[0146]

[0147] Where AF 2i is the acceleration factor of the ith component in the servo drive; T u is the preset test temperature of the servo drive; T a Ea is the reference operating temperature of the servo drive under rated conditions; i is the activation energy of the i-th component in the driver, in eV; K is the Boltzmann constant, which is 8.6173×10-5eV / K.

[0148] Step S446: Calculate the servo driver acceleration factor according to the failure rate and acceleration factor of each component.

[0149] As mentioned above, the servo drive acceleration factor can be calculated based on the barrel effect, series model or parallel model. Taking the series model as an example, the life model t of the servo drive under rated conditions is 20The life model t2 under the preset load conditions is:

[0150]

[0151]

[0152] In the formula, λ 2i is the failure rate of the ith component under rated conditions; λ′ 2i is the failure rate of the ith component under the preset load condition; λs is the failure rate of the servo drive under rated conditions; λ′ s is the failure rate of the servo drive under preset load conditions; n is the number of components that need to be considered in the failure rate calculation.

[0153] The servo drive acceleration factor AF2 is:

[0154]

[0155] Substituting equations (18) and (19) into equation (20), the acceleration factor of the servo drive can be calculated.

[0156] In the above embodiment, a specific calculation process of the servo drive acceleration factor is given. During the calculation process, the component composition and operating parameters of the servo drive, as well as the external load conditions it is subjected to, are fully considered, which is conducive to improving the accuracy of the acceleration factor and thereby enhancing the credibility of the life test method.

[0157] In one embodiment, the servo system parameters include the number of servo systems put into life test, the mean time between failures under rated conditions, and the type of reliability test statistical scheme, such as Figure 7 As shown, step S600 includes step S620 and step S640.

[0158] Step S620: Determine the reference life test time of the servo system according to the mean time between failures under rated conditions and the type of reliability test statistical scheme.

[0159] Among them, the reliability test statistical scheme types include the probability ratio sequential test scheme, the timed truncation test scheme and the full test scheme specified in GJB899. According to different statistical scheme types and their corresponding statistical parameters, the ratio θ1 of the benchmark life test time and the mean time between failures under rated conditions can be determined. Combined with the mean time between failures under rated conditions MTBF, the benchmark life test time T of the servo system can be determined. 总 .

[0160] T 总 =θ1*MTMF (21)

[0161] Taking the timed truncation test scheme as an example, we can determine θ1 based on the statistical parameters, that is, the specific values ​​of the producer risk α and the user risk β, and the corresponding relationship between the pre-stored statistical parameters and θ1, and then substitute it into formula (21) to obtain T 总 For example, when α = 30% and β = 30%, we can get θ1 to be 1.204, that is, T 总 =1.204*MTBF. The corresponding relationship between the statistical parameters and θ1 is established according to the relevant provisions of GJB899.

[0162] Step S640: Determine the accelerated life test time according to the reference life test time, the number of servo systems and the servo system acceleration factor.

[0163] Specifically, the accelerated life test time T can be determined according to the following formula:

[0164] T=T 总 ÷AF÷N (22)

[0165] Where N is the number of servo systems put into life test.

[0166] In the above embodiment, a specific method for determining the accelerated life test time in the accelerated life test is provided. By using multiple test samples to synchronously perform the accelerated life test, the test time can be further shortened and the test efficiency can be improved.

[0167] It should be understood that, although each step in each flow chart involved in the above-described embodiment is shown in sequence according to the indication of the arrow, these steps are not necessarily performed in sequence according to the order indicated by the arrow. Unless there is a clear explanation in this article, the execution of these steps does not have strict order restrictions, and these steps can be performed in other orders. Moreover, at least a portion of the steps in each flow chart involved in the above-described embodiment may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these sub-steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0168] In the second aspect of this application, Figure 8As shown, a servo system life test device is provided, including: an acquisition module 200, used to acquire servo system parameters and preset load conditions for servo system life test; the load value under the preset load condition is greater than the corresponding load value under the rated working condition; the preset load condition includes the axial force load condition and radial force load condition of the servo motor, and the temperature load condition of the servo driver; an acceleration factor calculation module 400, used to calculate the servo system acceleration factor according to the axial force load condition, radial force load condition, temperature load condition and servo system parameters; an accelerated life test time determination module 600, used to determine the accelerated life test time according to the servo system parameters and the servo system acceleration factor; an output module 800, used to output a life test start instruction; the life test start instruction is used to instruct the user to apply the preset load condition to the servo system to be tested within the accelerated life test time to perform a servo system life test.

[0169] In one embodiment, Fig. 9 As shown, the acceleration factor calculation module 400 includes: a servo motor acceleration factor calculation unit 420, which is used to calculate the servo motor acceleration factor according to the axial force load condition and the radial force load condition, as well as the servo system parameters; a servo driver acceleration factor calculation unit 440, which is used to calculate the servo driver acceleration factor according to the temperature load condition and the servo system parameters; and an acceleration factor determination unit 460, which is used to determine the servo system acceleration factor according to the servo motor acceleration factor and the servo driver acceleration factor.

[0170] In one embodiment, the servo system parameters include servo motor operating parameters and bearing parameters on the servo motor. Fig.10 As shown, the servo motor acceleration factor calculation unit 420 includes: a baseline life calculation component 422, which is used to obtain the baseline life of the servo motor under rated conditions according to the servo motor working parameters and bearing parameters; an accelerated life calculation component 424, which is used to obtain the accelerated life of the servo motor under preset load conditions according to the servo motor working parameters and bearing parameters, as well as axial force load conditions and radial force load conditions; a servo motor acceleration factor calculation component 426, which is used to calculate the servo motor acceleration factor according to the baseline life and the accelerated life.

[0171] In one embodiment, the reference life calculation component 422 is specifically used to: calculate the equivalent dynamic load of the corresponding bearing under rated conditions based on the bearing parameters; and obtain the reference life of the servo motor under rated conditions based on the servo motor working parameters, bearing parameters and equivalent dynamic load.

[0172] In one embodiment, the servo system parameters include the component composition and operating parameters of the servo drive. Fig.11As shown, the servo drive acceleration factor calculation unit 440 includes: a component failure rate calculation component 442, which calculates the failure rate of each component under rated conditions according to the component composition and operating parameters of the servo drive; a component acceleration factor calculation component 444, which calculates the acceleration factor of each component according to the component composition and operating parameters of the servo drive, as well as the temperature load conditions; and a servo drive acceleration factor calculation component 446, which calculates the servo drive acceleration factor according to the failure rate and acceleration factor of each component.

[0173] In one embodiment, the component acceleration factor calculation component 444 is specifically used to: determine the activation energy of each component according to the component composition of the servo drive and the correspondence between the component type and the activation energy; calculate the acceleration factor of each component according to the activation energy of each component and the temperature load conditions and operating parameters of the servo drive.

[0174] In one embodiment, the servo system parameters include the number of servo systems put into life test, the mean time between failures under rated conditions, and the type of statistical scheme for reliability test. Fig.12 As shown, the accelerated life test time determination module 600 includes: a benchmark life test time determination unit 620, which is used to determine the benchmark life test time of the servo system according to the mean trouble-free operating time under rated conditions and the reliability test statistical scheme type; an accelerated life test time determination unit 660, which is used to determine the accelerated life test time according to the benchmark life test time, the number of servo systems and the servo system acceleration factor.

[0175] The specific definition of the servo system life test device can be found in the definition of the servo system life test method above, which will not be repeated here. Each module in the above-mentioned servo system life test device can be implemented in whole or in part by software, hardware and their combination. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0176] In a third aspect of the present application, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Fig.13As shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a servo system life test method is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device housing, or an external keyboard, touchpad or mouse, etc.

[0177] Those skilled in the art will understand that Fig.13 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0178] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0179] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0180] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0181] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0182] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A servo system life test method, characterized in that: include: Obtain servo system parameters and preset load conditions for servo system life test; The load magnitude under the preset load condition is greater than the corresponding load magnitude under the rated working condition; The preset load conditions include the axial force load condition and radial force load condition of the servo motor, and the temperature load condition of the servo drive; Calculating a servo motor acceleration factor according to the axial force load condition and the radial force load condition, as well as the servo system parameters, wherein the servo motor acceleration factor is an acceleration factor of the weakest component of the servo motor, and the weakest component of the servo motor is obtained based on the stress conditions of various components of the servo motor under preset load conditions; Calculating a servo drive acceleration factor according to the temperature load condition and the servo system parameter, wherein the servo drive acceleration factor is an acceleration factor of the weakest component of the servo drive, and the weakest component of the servo drive is determined based on preset material properties of various components of the servo drive; Determining a servo system acceleration factor according to the servo motor acceleration factor and the servo driver acceleration factor; Determining an accelerated life test time according to the servo system parameters and the servo system acceleration factor; Output a life test start instruction; the life test start instruction is used to instruct the user to apply the preset load condition to the servo system to be tested within the accelerated life test time to perform a servo system life test.

2. The servo system life test method according to claim 1, characterized in that: The servo system parameters include servo motor operating parameters and bearing parameters on the servo motor; the servo motor acceleration factor is calculated according to the axial force load condition, the radial force load condition, and the servo system parameters, including: Obtaining a reference life of the servo motor under rated working conditions according to the servo motor operating parameters and the bearing parameters; According to the servo motor operating parameters and the bearing parameters, as well as the axial force load condition and the radial force load condition, the accelerated life of the servo motor under the preset load condition is obtained; The servo motor acceleration factor is calculated according to the reference life and the accelerated life.

3. The servo system life test method according to claim 2, characterized in that: The step of obtaining a reference life of the servo motor under rated working conditions according to the servo motor operating parameters and the bearing parameters comprises: According to the bearing parameters, the equivalent dynamic load of the corresponding bearing under rated working conditions is calculated; The reference life of the servo motor under rated working conditions is obtained according to the servo motor operating parameters, the bearing parameters and the equivalent dynamic load.

4. The servo system life test method according to claim 1, characterized in that: The servo system parameters include the component composition and working parameters of the servo driver; the servo driver acceleration factor is calculated according to the temperature load condition and the servo system parameters, including: Calculating the failure rate of each component under rated working conditions according to the component composition and operating parameters of the servo drive; Calculating the acceleration factor of each component according to the component composition and operating parameters of the servo drive and the temperature load conditions; The servo drive acceleration factor is calculated according to the failure rate and acceleration factor of each component.

5. The servo system life test method according to claim 4, characterized in that: The step of calculating the acceleration factor of each component according to the component composition and operating parameters of the servo drive and the temperature load condition includes: Determining the activation energy of each component according to the component composition of the servo drive and the corresponding relationship between the component type and the activation energy; The acceleration factor of each component is calculated according to the activation energy of each component, as well as the temperature load condition and working parameters of the servo drive.

6. The servo system life test method according to any one of claims 1 to 5, characterized in that: The servo system parameters include the number of servo systems put into life test, the mean time between failures under rated conditions and the type of statistical scheme for reliability test; Determining the accelerated life test time according to the servo system parameters and the servo system acceleration factor includes: Determine the reference life test time of the servo system according to the mean trouble-free working time under the rated working condition and the type of the reliability test statistical scheme; The accelerated life test time is determined according to the reference life test time, the number of servo systems and the servo system acceleration factor.

7. A servo system life test device, characterized in that: include: An acquisition module, used to acquire servo system parameters and preset load conditions for a servo system life test; The load value under the preset load condition is greater than the corresponding load value under the rated working condition; the preset load condition includes the axial force load condition and radial force load condition of the servo motor, and the temperature load condition of the servo drive; an acceleration factor calculation module, for calculating the servo motor acceleration factor according to the axial force load condition and the radial force load condition, and the servo system parameters, wherein the servo motor acceleration factor is the acceleration factor of the weakest component of the servo motor, and the weakest component of the servo motor is obtained based on the stress conditions of the various components of the servo motor under preset load conditions; calculating the servo drive acceleration factor according to the temperature load condition and the servo system parameters, wherein the servo drive acceleration factor is the acceleration factor of the weakest component of the servo drive, and the weakest component of the servo drive is determined based on preset material properties of the various components of the servo drive; determining the servo system acceleration factor according to the servo motor acceleration factor and the servo drive acceleration factor; An accelerated life test time determination module, used to determine the accelerated life test time according to the servo system parameters and the servo system acceleration factor; The output module is used to output a life test start instruction; the life test start instruction is used to instruct the user to apply the preset load condition to the servo system to be tested within the accelerated life test time to perform a servo system life test.

8. The servo system life test device according to claim 7, characterized in that: The servo system parameters include the servo motor operating parameters and the bearing parameters on the servo motor; the acceleration factor calculation module also includes: A reference life calculation component, used to obtain the reference life of the servo motor under rated working conditions according to the servo motor working parameters and the bearing parameters; An accelerated life calculation component, used to obtain the accelerated life of the servo motor under preset load conditions according to the servo motor operating parameters and the bearing parameters, as well as the axial force load conditions and the radial force load conditions; The servo motor acceleration factor calculation component is used to calculate the servo motor acceleration factor according to the reference life and the acceleration life.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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