A multi-stress coupling reliability accelerated test method for industrial robots

Abstract

The application discloses a kind of multi-stress coupling's industrial robot reliability accelerated test method, comprising the following steps: (1) in combination with application scene, according to standard, the safety and performance of industrial robot are detected and evaluated;(2) reliability accelerated test scene arrangement;(3) calculate reliability test time;(4) determine accelerated test reference condition;(5) carry out investigation test, including ontology mileage acceleration test, control cabinet high temperature stress test;(6) determine unified acceleration factor, calculate reliability acceleration time;(7) carry out reliability accelerated test;(8) carry out industrial robot reliability failure statistics and analysis and industrial robot safety and performance detection;(9) reliability evaluation is carried out to industrial robot.The application effectively combines using two methods of mileage acceleration and environmental temperature acceleration, obtains unified acceleration factor, and can more truly reflect the reliability level of robot under actual application scene.

Description

Technical Field

[0001] This invention belongs to the field of industrial robot reliability testing technology, specifically, it relates to an accelerated testing method for the reliability of industrial robots with multi-stress coupling, and in particular, an accelerated testing method for the reliability of industrial robots based on temperature and speed coordination. Background Technology

[0002] Currently, my country has become the world's largest market for industrial robot manufacturing and application, possessing a highly concentrated and complete industrial system. This system encompasses the entire industrial chain, including core components, robot bodies, system integration, and applications, giving China a significant position in the global robotics industry. However, domestically produced industrial robots have a relatively low market share in high-end applications.

[0003] Reliability is a key indicator of industrial robot product quality and a crucial factor influencing market share. As core equipment in industrial manufacturing, the reliability level of industrial robots directly affects production stability, efficiency, and safety. Industrial robot reliability refers to the robot's ability to perform its intended function without failure within a specified timeframe under defined environmental conditions and usage scenarios. It emphasizes three key elements: defined conditions, defined time, and intended function, ensuring reliable operation of the robot in specific scenarios. Reliability testing systematically evaluates the robot's failure rate, lifespan, and performance degradation patterns by simulating the long-term operating conditions of industrial robots under actual working conditions.

[0004] The mean operating time between failures (MTBF) is a commonly used indicator in existing national standards to measure the reliability level of industrial robots. The robot reliability (MTBF) assessment test refers to the ratio of the total number of product life units to the number of failures under specified conditions and within a specified period. The higher the MTBF value, the longer the average failure time of the product in a certain period, indicating that the robot has a higher reliability level and a lower failure and maintenance frequency during the product life cycle. Summary of the Invention

[0005] The purpose of this invention is to provide an accelerated testing method for the reliability of industrial robots with multi-stress coupling.

[0006] The above-mentioned objective of this invention can be achieved through the following technical solution: an accelerated testing method for the reliability of industrial robots with multi-stress coupling, comprising the following steps:

[0007] (1) Combine application scenarios and conduct safety and performance testing and evaluation of industrial robots in accordance with standards;

[0008] (2) Reliability accelerated test scenario setup;

[0009] (3) Calculate the reliability test time;

[0010] (4) Determine the baseline conditions for accelerated testing;

[0011] (5) Conduct preliminary tests, including accelerated mileage tests of the industrial robot body and accelerated high-temperature stress tests of the control cabinet;

[0012] (6) Determine the unified acceleration factor and calculate the reliability acceleration time;

[0013] (7) Conduct accelerated reliability testing;

[0014] (8) Conduct statistical analysis of industrial robot reliability failures and safety and performance testing of industrial robots;

[0015] (9) Evaluate the mean time between failures (MTBF) of industrial robots for reliability.

[0016] In the above-mentioned accelerated testing method for the reliability of industrial robots under multi-stress coupling:

[0017] Preferably, the application scenario described in step (1) includes glue application; in step (1), the glue application trajectory speed of the industrial robot during operation is specified to be 200 mm / s, and the repeatability positioning accuracy is <0.1 mm.

[0018] Preferably, the reliability accelerated test scenario setup in step (2) includes:

[0019] (2.1) Test equipment: industrial robot body, rated load on the industrial robot body, industrial robot control cabinet and teach pendant;

[0020] (2.2) Testing equipment: environmental test chamber, multi-channel temperature monitoring instrument, multiple sets of temperature sensors, fluorite monitoring camera, laser tracking system and integrated safety instrument;

[0021] The industrial robot body is equipped with a rated load and fixed. The Ezviz surveillance camera is used to monitor the operating status of the industrial robot body in real time. The control cabinet is placed in an environmental test chamber. Multiple temperature sensor probes are installed at the core components inside the control cabinet. The temperature of each core component is monitored in real time by an external multi-channel temperature monitoring instrument. The teach pendant is placed outside the environmental test chamber. A laser tracker is used to test the process accuracy. A comprehensive safety instrument is used to evaluate whether the industrial robot is safe.

[0022] Preferably, in step (2.1), the rated load on the industrial robot body is 300kg; in step (2.2), each industrial robot uses 12 sets of temperature sensor probes installed in the core components inside the control cabinet.

[0023] Preferably, the calculation of reliability test time in step (3) includes: according to the relevant requirements of standard GB / T 39266-2020 "Reliability Requirements and Test Methods for Mechanical Environment of Industrial Robots" and GB / T 39590.1-2020 "Robot Reliability Part 1: General Guidelines", the test statistics method for industrial robot reliability time test is to adopt a time-truncation test scheme.

[0024] Preferably, determining the accelerated test baseline conditions in step (4) includes:

[0025] (4.1) The industrial robot body adopts the mileage acceleration test method. Combined with the basic requirements of industrial robots in actual application scenarios, the acceleration trajectory of industrial robots in actual application scenarios is set. According to the standard GB / T 12642-2013 "Industrial Robot Performance Test Method", the running trajectory of industrial robot performance test is specified, and the benchmark running speed is set to be the same as the speed of actual application scenario operation.

[0026] (4.2) Industrial robot control cabinet: In practical applications, the most common problem of control cabinet failure is overheating of internal core components. Therefore, the environmental temperature stress test method is adopted, and 25°C under normal temperature is specified as the reference temperature of key components of the control cabinet. By setting different high temperature conditions in the environment, the reliability life is evaluated according to the Arrhenius theoretical model.

[0027] (4.3) Industrial robot system performance: In the early, middle and late stages of the accelerated reliability test of industrial robots, the evaluation of the performance degradation of industrial robot systems should meet the following two requirements: ① Comply with the safety specifications and requirements of standard GB 11291.1-2011 "Safety requirements for robots for industrial environments - Part 1: Robots"; ② Repeat positioning accuracy < 0.1 mm.

[0028] Preferably, in step (4.1), the reference running speed is set to be the same as the speed of actual application scenario operation, based on the running trajectory of industrial robot performance test as specified in standard GB / T 12642-2013 "Industrial Robot Performance Test Method".

[0029] For example, in practical applications such as glue application, to ensure that the industrial robot always operates normally under its rated load, P1-P2-P3-P4-P5 (e.g., ...) can be used. Figure 1 The test trajectory (as shown) serves as the reference trajectory for the operation of the industrial robot body, and the reference running speed is set to be the same as the glue application speed of 200 mm / s.

[0030] In a preferred embodiment of the present invention, step (4.1) employs an odometer acceleration test method for the industrial robot body. Combining the basic requirements of the industrial robot in specific application scenarios, such as adhesive application, the accelerated coating trajectory of the industrial robot in the actual adhesive application scenario is set. The coating trajectory is set as PA–PB, as follows: Figure 6 As shown.

[0031] Preferably, the preliminary test in step (5) includes:

[0032] (5.1) Industrial robot body mileage acceleration test: Two industrial robots were run at a reference speed under a rated load of 300kg to run the reference trajectory of the actual application scenario. The running cycle was 30min. By recording the trajectory distance and running time each time, the mileage speed V1 of the industrial robot body reference trajectory was calculated. The industrial robot body was in a thermally stable state and was set to run continuously for 10min at different program speeds of 1000mm / s, 1200mm / s, 1400mm / s and 1600mm / s respectively. The trajectory distance and running time of the industrial robot body at different speeds were recorded. The mileage speed V2 of the industrial robot body in the actual application scenario trajectory was calculated. Finally, the acceleration factor of the industrial robot body was calculated by V2 / V1.

[0033] (5.2) High-temperature stress acceleration test of industrial robot control cabinet: The control cabinet was placed in an environmental test chamber, and multiple temperature sensor probes were installed on the core components inside the control cabinet. An external temperature monitoring instrument was connected to monitor the temperature changes of each core component of the control cabinet in real time. The environmental test chamber was set to run continuously at a reference temperature of 25℃ for 2 hours to reach thermal stability. The reference temperature of each core component of the control cabinet was recorded by the external temperature monitoring instrument. The environmental test chamber was set to maintain a constant high temperature environment of 45℃, 50℃, and 55℃. The industrial robot body was set to run continuously at different program speeds of 1200mm / s, 1400mm / s, and 1600mm / s on the actual application scenario trajectory for 2 hours to reach thermal stability. The temperature changes of the core components inside the control cabinet were recorded by the temperature monitoring instrument. The acceleration factor of each core component in the high-temperature environment was calculated according to the Arrhenius model.

[0034] (5.3) Select the most representative acceleration factor of the control cabinet: Based on the actual situation of the trajectory of the industrial robot body acceleration operation in actual application scenarios, the driver module is one of the core components of the control cabinet. The driver module is most sensitive to high temperature environment. It controls the coding of each joint axis and motor operation of the industrial robot. The internal structure circuit is the most complex, involving the most components and the highest failure risk coefficient. Selecting the driver shell as the most representative acceleration factor of the control cabinet is the most representative.

[0035] Preferably, in step (6), determining the uniform acceleration factor and calculating the reliability acceleration time includes:

[0036] (6.1) Determine a unified acceleration factor: The industrial robot body and the control cabinet adopt different preliminary tests and acceleration methods. In order to ensure the consistency and effectiveness of the reliability acceleration test of the industrial robot system, the acceleration factors of the industrial robot body and the control cabinet should be comparable. Based on the preliminary tests of the industrial robot body and the control cabinet, and taking into account the trajectory operation of the industrial robot in the actual application scenario and the acceptable range of constant high temperature in the control cabinet environment, it is determined that the industrial robot body will be tested at a speed of 1600 mm / s in the actual application scenario. The acceleration factor obtained by the body is calculated. The acceleration factor of the control cabinet is determined to be the high temperature stress of 55℃ in the environmental test chamber for the inner drive shell. The acceleration factor is calculated.

[0037] (6.2) Calculate reliability acceleration time: The data obtained from the preliminary test shows that the acceleration factor difference of each industrial robot body and control cabinet is similar, which ensures the consistency of industrial robot reliability acceleration test. The lowest acceleration factor is selected uniformly, and the reliability acceleration time of each industrial robot is obtained by calculating the acceleration time of the reliability test.

[0038] Preferably, the test plan for the reliability acceleration test in step (7) is as follows: the control cabinet of the same batch of industrial robots as in the preliminary test is kept under an ambient temperature stress of 55°C, the industrial robot body runs the actual application scenario trajectory at 1600mm / s, and the continuous running time of each industrial robot is the reliability acceleration time.

[0039] Preferably, step (8) includes industrial robot reliability fault statistics and analysis, as well as industrial robot safety and performance testing, which includes:

[0040] (8.1) Industrial robot reliability failure statistics and analysis: Based on the evaluation requirements of the failure criteria and statistical principles in Clause 6.4.4 of the standard GB-T 39266-2020 "Industrial Robot Mechanical Environment Reliability Requirements and Test Methods", the failure problems that occur in the entire process of industrial robot reliability accelerated testing are statistically analyzed.

[0041] (8.2) Safety and performance testing of industrial robots: In accordance with the relevant requirements of standard GB 11291.1-2011 "Safety requirements for robots for industrial environments - Part 1: Robots", safety items of the tested industrial robots were tested in the early, middle and late stages of the accelerated reliability test, and all were required to meet the relevant criteria of the judgment standard. In accordance with the relevant requirements of standard GB / T 12642-2013 "Performance specifications and test methods for industrial robots", and according to the test requirements of the position repeatability of industrial robots in clause 7.2 of the standard, the performance of the industrial robots was tested in the early, middle and late stages of the accelerated reliability test, and all were required to meet the requirement that the repeatability of the industrial robot in the actual application scenario is less than 0.1 mm.

[0042] Preferably, the mean time between failures (MTBF) evaluation of the industrial robot in step (9) includes: if all tested industrial robots have reached the reliability acceleration test time, no statistically significant faults are detected during the entire acceleration test, and the safety items of the industrial robot in the early, middle and late stages of the acceleration test meet the requirements of the standard, and the repeatability accuracy test data meets the accuracy requirement of 0.1mm in the actual application scenario, then the mean time between failures (MTBF) of the tested industrial robot has passed 40,000 hours, and the reliability level of the industrial robot is high.

[0043] Compared with the prior art, the present invention has the following advantages:

[0044] (1) Comprehensive Accelerated Testing Scheme: This invention innovatively combines two methods: mileage acceleration and ambient temperature acceleration. Mileage acceleration is used for the industrial robot body to simulate actual application scenarios, such as the actual scenario of gluing operation, and different running speeds are set. The appropriate acceleration conditions are determined by comparing the acceleration factors under different speeds. Ambient temperature stress acceleration is used for the control cabinet to monitor the temperature changes of key components under different high temperature environments to obtain the appropriate acceleration factors. Compared with the traditional single acceleration test method, this is more comprehensive and scientific, and can more realistically reflect the reliability level of industrial robots under actual application scenarios.

[0045] (2) Method for determining the acceleration factor: When determining the acceleration factor for reliability testing, this invention not only considers the acceleration of the industrial robot body and the control cabinet, but also focuses on the matching of their acceleration factors. Through preliminary tests, the acceleration factors of the robot body under different speed conditions and the control cabinet under different ambient temperature conditions are compared. Finally, the acceleration factor that is comparable to and the lowest of the two acceleration factors is selected as the unified acceleration factor for reliability acceleration testing, which ensures the consistency and scientific nature of the whole machine reliability acceleration test. This method of comprehensively analyzing and determining the acceleration factor is innovative.

[0046] (3) Closely aligned with actual application scenarios: This invention closely revolves the reliability acceleration test around the actual application scenarios of industrial robots, such as glue application operations. From setting the glue application trajectory speed and repeatability accuracy requirements of the robot under the benchmark conditions, to selecting the benchmark trajectory that meets the needs of glue application operations for testing, it fully considers the actual working conditions, so that the test results can directly reflect the reliability performance of industrial robots in actual application scenarios. It has important guiding significance for evaluating the performance of robots in real working environments and provides a strong evaluation basis for manufacturers to improve product quality to better meet market demands.

[0047] (4) Comprehensive evaluation of reliability indicators: This invention applies both mechanical motion and environmental temperature stress to the entire industrial robot at different stages of reliability testing. It tests the safety items of the entire robot according to the national standard GB 11291.1-2011, and tests the repeatability accuracy of the entire robot according to the national standard GB / T 12642-2013. Both need to meet the requirements of specific application scenarios, more realistically reflect the multi-factor coupled failure modes in actual scenarios, improve the coverage of reliability testing, and have strong practicality. Attached Figure Description

[0048] The present invention will now be further described with reference to the accompanying drawings and embodiments.

[0049] Figure 1 This is the reference trajectory for the industrial robot's motion in Example 2;

[0050] Figure 2 This is a cross-sectional view of the reference trajectory of the industrial robot body in Example 2;

[0051] Figure 3 This is a cross-sectional view of the accelerated mileage assessment test of the industrial robot in Example 2;

[0052] Figure 4 This is a cross-sectional view of the temperature stress preliminary test of the control cabinet in Example 2;

[0053] Figure 5 This is a flowchart of the reliability assessment test for the industrial robot (300kg load, a heavy-duty robot) in Example 2;

[0054] Figure 6 This is a schematic diagram of the accelerated reliability testing scheme for industrial robots in Example 2;

[0055] Figure 7 This is a physical image of the industrial robot reliability acceleration test site in Example 2;

[0056] Figure 8 This is a photograph of the two control cabinets placed in an environmental test chamber for temperature stress testing in Example 2.

[0057] Figure 9 Wiring diagram (front and back) of temperature probe monitoring for the core components of the control cabinet in Example 2 (Group 1);

[0058] Figure 10 Wiring diagram (front and back) of the temperature probe monitoring core component of the control cabinet in Example 2;

[0059] Figure 11 This is a flowchart of the accelerated reliability testing method for industrial robots with multi-stress coupling in Example 2. Detailed Implementation

[0060] To make the design scheme, test methods, and technical advantages of the present invention clearer, a detailed description is now provided in conjunction with the accompanying drawings and specific examples of the test methods. It should be understood that the specific examples described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0061] Example 1

[0062] The accelerated testing method for the reliability of industrial robots with multi-stress coupling provided in this embodiment includes the following steps:

[0063] (1) Combine application scenarios and conduct testing and evaluation of the safety and performance of industrial robots in accordance with standards;

[0064] For example: the application scenario described in step (1) includes glue application; step (1) specifies that the glue application trajectory speed of the industrial robot is 200mm / s and the repeatability positioning accuracy is <0.1mm.

[0065] (2) Reliability accelerated test scenario setup;

[0066] Step (2) includes setting up the reliability accelerated test scenario:

[0067] (2.1) Test equipment: industrial robot body, rated load on the industrial robot body, industrial robot control cabinet and teach pendant;

[0068] (2.2) Testing equipment: environmental test chamber, multi-channel temperature monitoring instrument, multiple sets of temperature sensors, fluorite monitoring camera, laser tracking system and integrated safety instrument;

[0069] The industrial robot body is equipped with a rated load and fixed. The operating status of the industrial robot body is monitored in real time using an Ezviz surveillance camera. The control cabinet is placed in an environmental test chamber. Multiple sets of temperature sensor probes are installed at the core components inside the control cabinet. The temperature of each core component is monitored in real time by an external multi-channel temperature monitoring instrument. The teach pendant is placed outside the environmental chamber. A laser tracker is used to test the process accuracy. A comprehensive safety instrument is used to evaluate whether the industrial robot is safe.

[0070] (3) Calculate the reliability test time;

[0071] For example, the calculation of reliability test time in step (3) includes: according to the relevant requirements of standard GB / T 39266-2020 "Reliability Requirements and Test Methods for Mechanical Environment of Industrial Robots" and GB / T 39590.1-2020 "Robot Reliability Part 1: General Guidelines", the test statistics method for industrial robot reliability time test is to adopt the time-truncated test scheme.

[0072] (4) Determine the baseline conditions for accelerated testing;

[0073] Step (4) involves determining the accelerated test baseline conditions, including:

[0074] (4.1) The industrial robot body adopts the mileage acceleration test method. Combined with the basic requirements of industrial robots in actual application scenarios, the acceleration trajectory of industrial robots in actual application scenarios is set. According to the standard GB / T 12642-2013 "Industrial Robot Performance Test Method", the running trajectory of industrial robot performance test is specified, and the benchmark running speed is set to be the same as the speed of actual application scenario operation.

[0075] (4.2) Industrial robot control cabinet: In practical applications, the most common problem of control cabinet failure is overheating of internal core components. Therefore, the environmental temperature stress test method is adopted, and 25°C under normal temperature is specified as the reference temperature of key components of the control cabinet. By setting different high temperature conditions in the environment, the reliability life is evaluated according to the Arrhenius theoretical model.

[0076] (4.3) Industrial robot system performance: In the early, middle and late stages of the accelerated reliability test of industrial robots, the evaluation of the performance degradation of industrial robot systems should meet the following two requirements: ① Comply with the safety specifications and requirements of standard GB 11291.1-2011 "Safety requirements for robots for industrial environments - Part 1: Robots"; ② Repeat positioning accuracy < 0.1 mm.

[0077] (5) Two industrial robots under test were used for preliminary tests, including body mileage acceleration test and control cabinet high temperature stress test;

[0078] The preliminary test in step (5) includes:

[0079] (5.1) Industrial robot body mileage acceleration test: Two industrial robots were run at a reference speed under a rated load of 300kg to run the reference trajectory of the actual application scenario. The running cycle was 30min. By recording the trajectory distance and running time each time, the mileage speed V1 of the industrial robot body reference trajectory was calculated. The industrial robot body was in a thermally stable state and was set to run continuously for 10min at different program speeds of 1000mm / s, 1200mm / s, 1400mm / s and 1600mm / s respectively. The trajectory distance and running time of the industrial robot body at different speeds were recorded. The mileage speed V2 of the industrial robot body in the actual application scenario trajectory was calculated. Finally, the acceleration factor of the industrial robot body was calculated by V2 / V1.

[0080] (5.2) High-temperature stress acceleration test of industrial robot control cabinet: The control cabinet is placed in an environmental test chamber, and multiple temperature sensor probes are installed on the core components inside the control cabinet. An external temperature monitoring instrument is connected to monitor the temperature changes of each core component of the control cabinet in real time. The environmental test chamber is set to run continuously at a reference temperature of 25℃ for 2 hours to reach thermal stability. The reference temperature of each core component of the control cabinet is recorded by the external temperature monitoring instrument. The environmental test chamber is set to maintain a constant high temperature environment of 45℃, 50℃, and 55℃. The industrial robot body is set to run continuously at different program speeds of 1200mm / s, 1400mm / s, and 1600mm / s on the actual application scenario trajectory for 2 hours to reach thermal stability. The temperature changes of the core components inside the control cabinet are recorded by the temperature monitoring instrument. The acceleration factor of each core component in the high-temperature environment can be calculated according to the Arrhenius model.

[0081] (5.3) Select the most representative acceleration factor of the control cabinet: Based on the actual situation of the trajectory of the robot body acceleration operation in the actual application scenario, the driver module is one of the core components of the control cabinet. The driver module is most sensitive to high temperature environment. It controls the coding of each joint axis of the robot and the operation of the motor. The internal structure circuit is the most complex, involving the most components and the highest failure risk coefficient. Therefore, the driver shell is selected as the most representative acceleration factor of the control cabinet.

[0082] (6) Determine the unified acceleration factor and calculate the reliability acceleration time;

[0083] Step (6) involves determining the uniform acceleration factor and calculating the reliability acceleration time, including:

[0084] (6.1) Determine a unified acceleration factor: The industrial robot body and the control cabinet adopt different preliminary tests and acceleration methods. In order to ensure the consistency and effectiveness of the reliability acceleration test of the industrial robot system, the acceleration factors of the industrial robot body and the control cabinet should be comparable. Based on the preliminary tests of the industrial robot body and the control cabinet, and taking into account the trajectory operation of the industrial robot in the actual application scenario and the acceptable range of constant high temperature in the control cabinet environment, it is determined that the industrial robot body will be tested at a speed of 1600 mm / s in the actual application scenario. The acceleration factor obtained by the body is calculated. The acceleration factor of the control cabinet is determined to be the high temperature stress of the drive shell in the environmental chamber at 55℃. The acceleration factor is calculated.

[0085] (6.2) Calculate reliability acceleration time: The data obtained from the preliminary test shows that the acceleration factor difference of each industrial robot body and control cabinet is similar, which ensures the consistency of industrial robot reliability acceleration test. The lowest acceleration factor is selected uniformly, and the reliability acceleration time of each industrial robot is obtained by calculating the acceleration time of the reliability test.

[0086] (7) Conduct accelerated reliability testing;

[0087] The test plan for the reliability acceleration test in step (7) is as follows: the control cabinet of the industrial robot in the same batch as the preliminary test is kept at an ambient temperature stress of 55°C, the industrial robot body runs the actual application scenario trajectory at 1600mm / s, and the continuous running time of each industrial robot is the reliability acceleration time.

[0088] (8) Conduct statistical analysis of industrial robot reliability failures and safety and performance testing of industrial robots;

[0089] Step (8) includes statistical analysis of industrial robot reliability failures and safety and performance testing of industrial robots, including:

[0090] (8.1) Industrial robot reliability failure statistics and analysis: Based on the evaluation requirements of the failure criteria and statistical principles in Clause 6.4.4 of the standard GB-T 39266-2020 "Industrial Robot Mechanical Environment Reliability Requirements and Test Methods", the failure problems that occur in the entire process of industrial robot reliability accelerated testing are statistically analyzed.

[0091] (8.2) Safety and performance testing of industrial robots: In accordance with the relevant requirements of standard GB 11291.1-2011 "Safety requirements for robots for industrial environments - Part 1: Robots", safety items of the tested industrial robots were tested in the early, middle and late stages of the accelerated reliability test, and all were required to meet the relevant criteria of the judgment standard. In accordance with the relevant requirements of standard GB / T 12642-2013 "Performance specifications and test methods for industrial robots", and according to the test requirements of the position repeatability of industrial robots in clause 7.2 of the standard, the performance of the industrial robots was tested in the early, middle and late stages of the accelerated reliability test, and all were required to meet the requirement that the repeatability of the industrial robot in the actual application scenario is less than 0.1 mm.

[0092] (9) Evaluate the mean time between failures (MTBF) of industrial robots for reliability.

[0093] Step (9) includes the following: if all tested industrial robots have reached the reliability acceleration test time, no statistically significant faults are detected during the entire acceleration test, and the safety items of the industrial robots in the early, middle and late stages of the acceleration test meet the requirements of the standard, and the repeatability accuracy test data meets the accuracy requirement of 0.1mm in the actual application scenario, then the mean time between failures (MTBF) of the tested industrial robots has passed 40,000 hours, and the reliability level of the industrial robots is high.

[0094] Example 2

[0095] Taking adhesive application as an example, this embodiment starts from the actual application scenario of industrial robots, conducts accelerated reliability testing of industrial robots, and realizes rapid evaluation of the MTBF index of industrial robots, such as... Figure 11 As shown, the details are as follows:

[0096] To achieve the goal of reliability evaluation of industrial robots for specific application scenarios, this embodiment provides an accelerated reliability testing method for industrial robots with multi-stress coupling, which includes the following steps:

[0097] (1) Application scenario requirements

[0098] To ensure the quality of adhesive application in specific application scenarios, the adhesive application trajectory speed of industrial robots is specified to be 200 mm / s, and the repeatability positioning accuracy is <0.1 mm.

[0099] (2) Reliability accelerated test scenario setup (e.g.) Figure 7-10 ):

[0100] (2.1) Test equipment: The test object is an industrial robot used in glue application scenarios, including the industrial robot body, the rated load on the industrial robot body, the industrial robot control cabinet and the teach pendant;

[0101] (2.2) Testing equipment: environmental test chamber, multi-channel temperature monitoring instrument, multiple sets of temperature sensors, fluorite monitoring camera, Leica laser tracker system, integrated safety instrument MI3394;

[0102] The industrial robot body is equipped with a rated load and fixed. The Ezviz surveillance camera is used to monitor the operating status of the industrial robot body in real time. The control cabinet is placed in an environmental test chamber. Multiple temperature sensor probes are installed at the core components inside the control cabinet. The temperature of each core component is monitored in real time by an external multi-channel temperature monitoring instrument. The teach pendant is placed outside the environmental test chamber. A laser tracker is used to test the process accuracy. A comprehensive safety instrument is used to evaluate whether the industrial robot is safe.

[0103] To ensure the scientific rigor of the accelerated reliability test, two groups of industrial robots of the same specifications and models, two robots in each group, were used for the accelerated reliability test. Group 1 was selected for the preliminary test, while Group 2 was selected for the accelerated reliability test.

[0104] (3) Reliability test time

[0105] According to the relevant requirements of standards GB / T 39266-2020 "Reliability Requirements and Test Methods for Industrial Robots in Mechanical Environment" and GB / T39590.1-2020 "Robot Reliability Part 1: General Guidelines", the statistical test method for industrial robot reliability testing adopts a time-truncated test scheme (see Table 1 for details). Based on the statistical test scheme and the target value of the accelerated reliability test, the total test time T and the single-unit test time t are calculated using the following formulas:

[0106] T = θ l × m (1)

[0107] t = T / n (2)

[0108] Explanation of relevant parameters in the above formula: T: relevant experimental time, θ l : Lower limit of MTBF test, m: θ l × is a multiple of m, t is the test time for a single unit, and n is the number of products under test.

[0109] According to the above calculation formula (1), the target value X for the reliability test evaluation of industrial robots is 40,000 hours, and θ lWith a multiplier of 1.61, the total test time for reliability testing can be calculated to be 64,400 hours. This accelerated reliability test uses two industrial robots for testing. According to the above formula (2), the reliability test time T1 for each industrial robot can be calculated to be 32,200 hours.

[0110] Table 1 Statistical Scheme for Selecting Time-Cutoff Experimental Protocols

[0111]

[0112] (4) Industrial robot system baseline conditions:

[0113] (4.1) Industrial Robot Body: The industrial robot body adopts the odometer acceleration test method. Combined with the basic requirements of industrial robots in specific application scenarios, the acceleration trajectory of the industrial robot in the actual glue application scenario is set (the paint trajectory is set as: PA-PB). Figure 6 According to the standard GB / T 12642-2013 "Test Methods for Industrial Robot Performance", the running trajectory of the industrial robot performance test is as specified (see...). Figure 1 To ensure that the industrial robot always operates normally under rated load, the P1-P2-P3-P-P5 test trajectory is used as the reference trajectory for the operation of the industrial robot body, and the reference running speed is set to be the same as the glue application speed of 200mm / s.

[0114] (4.2) Industrial robot control cabinet: In practical applications, the most common problem of control cabinet failure is overheating of internal core components. Therefore, the environmental temperature stress test method is adopted, and 25°C under normal temperature is specified as the reference temperature of key components of the control cabinet. By setting different high temperature conditions in the environment, the reliability and life of the control cabinet are evaluated according to the Arrhenius theoretical model.

[0115]

[0116] According to the relevant parameters published above, Ea: activation energy, generally taken as 0.7 eV; t use : Usage time; t test Test time; T use Operating temperature; T test Test temperature; k: Boltzmann constant, typically 8.617 × 10⁻⁶. - 5 eV / K.

[0117] (4.3) Industrial robot system performance: In the early, middle and late stages of the accelerated reliability test of industrial robots, the evaluation of the performance degradation of industrial robot systems should meet the following two requirements: ① Comply with the safety specifications and requirements of standard GB 11291.1-2011 "Safety requirements for robots for industrial environments - Part 1: Robots"; ② Repeat positioning accuracy < 0.1 mm.

[0118] (5) Preliminary test

[0119] (5.1) Industrial robot body mileage acceleration test: A preliminary test was conducted using the two industrial robots from Group 1 mentioned above, such as... Figure 7 As shown, the robot body, under a rated load of 300kg, runs the reference trajectory P1-P2-P3-P4-P5 at a speed of 200mm / s. Figure 2 The baseline trajectory running profile shown is calculated by recording the trajectory travel and running time for each run in 30-minute cycles, and obtaining the mileage speed V1 of the baseline trajectory (see Table 2 for details).

[0120] Table 2. Robot Body Baseline Trajectory Running Test Data

[0121]

[0122] With the industrial robot body in a thermally stable state, it was continuously run for 10 minutes at different programmed speeds of 1000 mm / s, 1200 mm / s, 1400 mm / s, and 1600 mm / s. The trajectory distance and running time of the robot body at different speeds were recorded, and the mileage speed V2 of the robot body on the paint trajectory was calculated. Finally, the acceleration factor A of the robot body was calculated by V2 / V1 (see Table 3 for details). Figure 3 , Figure 11 ).

[0123] Table 3 Test data of the acceleration trajectory of the industrial robot body

[0124]

[0125] (5.2) High-Temperature Stress Accelerated Test of Industrial Robot Control Cabinet: The control cabinet was placed in an environmental test chamber, and 12 sets of temperature sensor probes marked with serial numbers were installed at the core components inside the control cabinet (see Table 4 for details). An external temperature monitoring instrument was connected to monitor the temperature changes of each core component of the control cabinet in real time. The environmental test chamber was set to run continuously at a reference temperature of 25℃ for 2 hours to reach thermal stability. The reference temperature of each core component of the control cabinet was recorded by the external temperature monitoring instrument (see Table 4 for details). The environmental chamber was set to maintain 45℃, 50℃, and 55℃ (tests showed that the industrial robot could reach thermal stability at 55℃, with the robot body continuously running the coating trajectory at different program speeds of 1200mm / s, 1400mm / s, and 1600mm / s for 2 hours). Figure 4 (The acceleration factor is highest at 55℃, so the following experiment was conducted at 55℃.) Under a constant high-temperature environment, the industrial robot body was set to continuously run the coating trajectory at different program speeds of 1200mm / s, 1400mm / s, and 1600mm / s for 2 hours to achieve thermal stability. The temperature changes of the core components inside the first control cabinet were recorded using a temperature monitoring instrument. The acceleration factor B of each core component under high-temperature conditions can be calculated according to the Arrhenius model (see Tables 5 and 6 for details). The flowchart of the industrial robot reliability baseline test is as follows: Figure 5 As shown.

[0126] Table 4. List of key component locations for temperature probe installation in the control cabinet

[0127]

[0128] Table 5. Temperature Stress Accelerated Determination Test Data for the Control Cabinet of the First Industrial Robot

[0129]

[0130]

[0131] Table 6. Temperature Stress Acceleration Test Data for the Control Cabinet of the Second Industrial Robot

[0132]

[0133]

[0134] (5.3) Considering the actual situation of the accelerated operation of the coating trajectory of the industrial robot body, the driver module is one of the core components of the control cabinet. The driver module is most sensitive to high temperature in the environment. It controls the coding of each joint axis and the operation of the motor of the industrial robot. Its internal structure and circuit are the most complex, involving the most components and the highest failure risk coefficient. Therefore, the driver housing is the most representative as the acceleration factor of the control cabinet (see Table 5 and Table 6 for details).

[0135] (6) Determine the uniform acceleration factor and calculate the reliability acceleration time.

[0136] (6.1) Determining a Uniform Acceleration Factor: Different baseline tests and acceleration methods were used for the industrial robot body and control cabinet. To ensure the consistency and effectiveness of the reliability acceleration tests for the industrial robot system, the acceleration factors for the robot body and control cabinet should be comparable. Based on the baseline tests of the robot body and control cabinet, and considering the robot's paint trajectory operation and the acceptable range of constant high temperature in the control cabinet environment, the robot body was tested at a speed of 1600 mm / s to calculate its acceleration factor. The internal actuator housing of the control cabinet was then used as the acceleration factor for the control cabinet under a 55°C high-temperature stress environment. The calculated acceleration factor is shown in Table 7. Figure 6 ).

[0137] (6.2) Calculation of reliability acceleration time: Data from the preliminary test shows that the acceleration factor differences for each industrial robot body and control cabinet are similar, ensuring the consistency of the industrial robot reliability acceleration test. To ensure the reasonableness and effectiveness of the industrial robot reliability acceleration test, the lowest acceleration factor C was uniformly selected as 13.65. Through the acceleration time calculation of the reliability test, the acceleration time for each industrial robot was found to be 2359 hours (see Table 7 for details).

[0138] Table 7 Acceleration factors and acceleration test times for the two industrial robots

[0139]

[0140]

[0141] Following accelerated reliability testing, safety and repeatability degradation data were combined with an accelerated reliability model to form a reliability assessment method based on specific application scenarios. This method determined an accelerated reliability testing scheme for industrial robots under multi-stress coupling. The control cabinet was maintained at an ambient temperature stress of 55°C, and the industrial robot body ran a coating trajectory at 1600 mm / s. Each industrial robot achieved a continuous operating time of 2359 hours, achieving a target value of 32200 hours. For details, please refer to the overall design scheme for accelerated reliability testing of industrial robots. Figure 11 (As shown).

[0142] (7) Conduct accelerated reliability testing

[0143] Two industrial robot bodies (Group 2) from the same batch as those in the preliminary test were randomly selected and operated at a speed of 1600 mm / s, with a constant temperature stress of 55°C in the control cabinet, and continuously running the coating trajectory PA-PB with a rated load of 300 kg until the accelerated test time of the robot system reached 2359 hours.

[0144] (8) Conduct reliability failure statistics and analysis of industrial robots and safety and performance testing of industrial robots.

[0145] (8.1) Statistics and analysis of reliability failures of industrial robots: Based on the evaluation requirements of the failure criteria and statistical principles in Clause 6.4.4 of the standard GB-T 39266-2020 "Requirements and test methods for mechanical environment reliability of industrial robots", the failure problems that occur in the whole process of robot reliability accelerated testing are statistically analyzed.

[0146] (8.1) Safety Specifications and Performance Testing of Industrial Robots: 1) In accordance with the relevant requirements of standard GB 11291.1-2011 "Safety Requirements for Robots in Industrial Environments Part 1: Robots", safety items were tested for the tested robot in the three stages of accelerated reliability testing: pre-test, mid-test, and post-test. All tests were required to meet the relevant criteria for judgment. 2) In accordance with the relevant requirements of standard GB / T 12642-2013 "Performance Specifications and Test Methods for Industrial Robots", and based on the robot position repeatability test requirements in clause 7.2 of the standard, performance tests were conducted on the robot in the three stages of accelerated reliability testing: pre-test, mid-test, and post-test. All tests were required to meet the requirement that the repeatability accuracy of the industrial robot in the specific application scenario is less than 0.1 mm.

[0147] (9) Robot reliability evaluation

[0148] The two tested industrial robots achieved a reliability acceleration test duration of 2359 hours. Throughout the accelerated test, no statistically significant faults were detected in accordance with the standard GB-T 39266-2020. Furthermore, all safety items of the industrial robots in the early, middle, and late stages of the accelerated test met the requirements specified in the standard. The repeatability accuracy test data met the accuracy requirement of 0.1 mm for the specific application scenario. Therefore, the mean time between failures (MTBF) of the tested industrial robots passed 40,000 hours. Thus, the method of this invention is reasonable and can verify the reliability of industrial robots.

[0149] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. An accelerated testing method for the reliability of industrial robots with multi-stress coupling, characterized in that, Includes the following steps: (1) Combine application scenarios and conduct safety and performance testing and evaluation of industrial robots in accordance with standards; (2) Reliability accelerated test scenario setup; (3) Calculate the reliability test time; (4) Determine the baseline conditions for accelerated testing; (5) Conduct preliminary tests, including accelerated mileage tests of the industrial robot body and accelerated high-temperature stress tests of the control cabinet; (6) Determine the uniform acceleration factor and calculate the reliability acceleration time; (7) Conduct accelerated reliability testing; (8) Conduct statistical analysis of industrial robot reliability failures and safety and performance testing of industrial robots; (9) Evaluate the mean time between failures (MTBF) of industrial robots for reliability. Step (4) determines the accelerated test baseline conditions, including: (4.1) The industrial robot body adopts the mileage acceleration test method. Combined with the basic requirements of industrial robots in actual application scenarios, the acceleration trajectory of industrial robots in actual application scenarios is set. According to the standard GB / T 12642-2013 "Industrial Robot Performance Test Method", the running trajectory of industrial robot performance test is specified, and the benchmark running speed is set to be the same as the speed of actual application scenario operation. (4.2) Industrial robot control cabinet: In practical applications, the most common problem of control cabinet failure is overheating of internal core components. Therefore, the environmental temperature stress test method is adopted, and 25℃ under normal temperature is specified as the reference temperature of key components of the control cabinet. By setting different high temperature conditions in the environment, the reliability life is evaluated according to the Arrhenius theoretical model. (4.3) Industrial robot system performance: In the early, middle and late stages of the accelerated reliability test of industrial robots, the evaluation of the performance degradation of industrial robot systems should meet the following two requirements: ① Comply with the safety specifications and requirements of standard GB 11291.1-2011 "Safety requirements for robots for industrial environments - Part 1: Robots"; ② Repeat positioning accuracy < 0.1 mm; The preliminary test in step (5) includes: (5.1) Industrial robot body mileage acceleration test: Two industrial robots were run at a reference speed under a rated load of 300kg to run the reference trajectory of the actual application scenario. The running cycle was 30min. The mileage speed V1 of the reference trajectory of the industrial robot body was calculated by recording the trajectory distance and running time each time. The industrial robot body was in a thermally stable state and was set to run continuously for 10min at different program speeds of 1000mm / s, 1200mm / s, 1400mm / s and 1600mm / s respectively. The trajectory distance and running time of the industrial robot body at different speeds were recorded. The mileage speed V2 of the industrial robot body in the actual application scenario trajectory was calculated. Finally, the acceleration factor of the industrial robot body was calculated by V2 / V1. (5.2) High-temperature stress acceleration test of industrial robot control cabinet: The control cabinet was placed in an environmental test chamber, and multiple temperature sensor probes were installed on the core components inside the control cabinet. An external temperature monitoring instrument was connected to monitor the temperature changes of each core component of the control cabinet in real time. The environmental test chamber was set to run continuously at a reference temperature of 25℃ for 2 hours to reach thermal stability. The reference temperature of each core component of the control cabinet was recorded by the external temperature monitoring instrument. The environmental test chamber was set to maintain a constant high temperature environment of 45℃, 50℃, and 55℃. The industrial robot body was set to run continuously at different program speeds of 1200mm / s, 1400mm / s, and 1600mm / s on the actual application scenario trajectory for 2 hours to reach thermal stability. The temperature changes of the core components inside the control cabinet were recorded by the temperature monitoring instrument. The acceleration factor of each core component in the high-temperature environment was calculated according to the Arrhenius model. (5.3) Select the most representative acceleration factor of the control cabinet: Based on the actual situation of the trajectory of the industrial robot body acceleration operation in the actual application scenario, the driver module is one of the core components of the control cabinet. The driver module is most sensitive to high temperature in the environment. It controls the coding of each joint axis and the operation of the motor of the industrial robot. The internal structure circuit is the most complex, involving the most components and the highest failure risk coefficient. Selecting the driver shell as the most representative acceleration factor of the control cabinet is the most representative. Step (6) involves determining the uniform acceleration factor and calculating the reliability acceleration time, including: (6.1) Determine a unified acceleration factor: The industrial robot body and the control cabinet adopt different preliminary tests and acceleration methods. In order to ensure the consistency and effectiveness of the reliability acceleration test of the industrial robot system, the acceleration factors of the industrial robot body and the control cabinet should be comparable. Based on the preliminary tests of the industrial robot body and the control cabinet, and taking into account the trajectory operation of the industrial robot in the actual application scenario and the acceptable range of constant high temperature in the control cabinet environment, it is determined that the industrial robot body will be tested at a speed of 1600 mm / s in the actual application scenario. The acceleration factor obtained by the body is calculated. The acceleration factor of the control cabinet is determined to be the high temperature stress of 55℃ in the environmental test chamber for the inner drive shell. The acceleration factor is calculated. (6.2) Calculate reliability acceleration time: The data obtained from the preliminary test shows that the acceleration factor difference of each industrial robot body and control cabinet is similar, which ensures the consistency of industrial robot reliability acceleration test. The lowest acceleration factor is selected uniformly, and the reliability acceleration time of each industrial robot is obtained by calculating the acceleration time of the reliability test.

2. The accelerated testing method for the reliability of industrial robots with multi-stress coupling according to claim 1, characterized in that, The application scenario described in step (1) includes glue application; step (1) specifies that the glue application trajectory speed of the industrial robot during operation is 200mm / s and the repeatability positioning accuracy is <0.1mm.

3. The accelerated testing method for the reliability of industrial robots with multi-stress coupling according to claim 1, characterized in that, Step (2) includes setting up the reliability accelerated test scenario: (2.1) Test equipment: industrial robot body, rated load on the industrial robot body, industrial robot control cabinet and teach pendant; (2.2) Testing equipment: environmental test chamber, multi-channel temperature monitoring instrument, multiple sets of temperature sensors, fluorite monitoring camera, laser tracking system and integrated safety instrument; The industrial robot body is equipped with a rated load and fixed. The Ezviz monitoring camera is used to monitor the operating status of the industrial robot body in real time. The control cabinet is placed in an environmental test chamber. Multiple temperature sensor probes are installed at the core components inside the control cabinet. The temperature of each core component is monitored in real time by an external multi-channel temperature monitoring instrument. The teach pendant is placed outside the environmental test chamber. A laser tracker is used to test the process accuracy. A comprehensive safety instrument is used to evaluate whether the industrial robot is safe.

4. The accelerated testing method for the reliability of multi-stress coupled industrial robots according to claim 1, characterized in that, The calculation of reliability test time in step (3) includes: according to the relevant requirements of standard GB / T 39266-2020 "Reliability Requirements and Test Methods for Mechanical Environment of Industrial Robots" and GB / T 39590.1-2020 "Robot Reliability Part 1: General Guidelines", the test statistical method for industrial robot reliability time test is to adopt the time-truncated test scheme.

5. The accelerated testing method for the reliability of industrial robots with multi-stress coupling according to claim 1, characterized in that, The reliability acceleration test in step (7) includes: maintaining the control cabinet of the industrial robot at an ambient temperature stress of 55°C, running the industrial robot body at a trajectory of 1600 mm / s in the actual application scenario, and the continuous running time of each industrial robot is the reliability acceleration time.

6. The accelerated testing method for the reliability of industrial robots with multi-stress coupling according to claim 1, characterized in that, Step (8) includes statistical analysis of industrial robot reliability failures and safety and performance testing of industrial robots, including: (8.1) Industrial robot reliability failure statistics and analysis: Based on the evaluation requirements of the failure criteria and statistical principles in Clause 6.4.4 of the standard GB-T 39266-2020 "Industrial Robot Mechanical Environment Reliability Requirements and Test Methods", the failure problems that occur in the entire process of industrial robot reliability accelerated testing are statistically analyzed. (8.2) Safety and performance testing of industrial robots: In accordance with the relevant requirements of standard GB 11291.1-2011 "Safety requirements for robots for industrial environments - Part 1: Robots", safety items of the tested industrial robots were tested in the early, middle and late stages of the accelerated reliability test, and all were required to meet the relevant criteria of the judgment standard. In accordance with the relevant requirements of standard GB / T12642-2013 "Performance specifications and test methods for industrial robots", and according to the test requirements of the position repeatability of industrial robots in clause 7.2 of the standard, the performance of the industrial robots was tested in the early, middle and late stages of the accelerated reliability test, and all were required to meet the requirement that the repeatability of the industrial robot in the actual application scenario is less than 0.1 mm.

7. The accelerated testing method for the reliability of multi-stress coupled industrial robots according to claim 1, characterized in that, The reliability mean time between failures (MTBF) evaluation of the industrial robot in step (9) includes: if all tested industrial robots have reached the reliability acceleration test time, no statistically significant faults are detected during the entire acceleration test, and the safety items of the industrial robot in the early, middle and late stages of the acceleration test meet the requirements of the standard, and the repeatability accuracy test data meets the accuracy requirement of 0.1 mm in the actual application scenario, then the MTBF of the tested industrial robot has passed 40,000 hours.

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