Controller accelerated life test method and apparatus based on multiple stress coupling

Abstract

This invention belongs to the field of automotive electronics reliability testing technology, and relates to a method and apparatus for accelerated life testing of controllers based on multi-stress coupling. The method includes: selecting an on-board electronic controller sample and performing performance testing; determining the core failure mechanism and stress limit boundary; constructing a multi-stress coupling life conversion model; designing a cyclic accelerated test profile; setting the test condition parameters of the on-board electronic controller sample; conducting accelerated life testing based on the cyclic accelerated test profile; determining the failure state of the on-board electronic controller sample according to multi-level failure criteria; solving the life conversion model using the failure data corresponding to the failure state; inputting the target operating condition parameters into the solved life conversion model; and calculating the corresponding actual service life according to a preset reliability target. This invention addresses industry pain points such as low life prediction accuracy, incomplete failure identification, and high verification costs for complex on-board electronic systems like smart cockpits throughout their entire lifecycle.

Description

Technical Field

[0001] This invention belongs to the field of automotive electronic reliability testing technology, and relates to a method and apparatus for accelerated life testing of controllers based on multi-stress coupling. Background Technology

[0002] With the rapid development of automotive intelligence and connectivity technologies, in-vehicle electronic controllers (such as intelligent cockpit domain controllers) have become core components of intelligent electric vehicles. Their integration level is more than 10 times higher than that of traditional ECUs, while also meeting the requirement of a long service life of 20-30 years for the entire vehicle. In actual service, the controller must continuously withstand the multi-stress coupling effects of temperature cycling, damp heat aging, random vibration, and dynamic electrical loads. According to industry statistics, more than 70% of failures in in-vehicle electronic systems originate from latent faults caused by multi-stress coupling, and single stress tests cannot reproduce these failure modes.

[0003] Traditional real-vehicle road testing faces three major insurmountable bottlenecks: (1) The cycle is as long as 3 to 5 years, which cannot match the 12 to 18 months R&D iteration cycle of intelligent vehicles; (2) The cost exceeds 10 million yuan per vehicle model and cannot cover extreme climate conditions worldwide; (3) The small sample size of failure data makes it difficult to support full life cycle reliability assessment. Therefore, accelerated life testing has become the core means to solve the problem of long life cycle verification.

[0004] However, existing accelerated life testing technologies for automotive electronics still have the following shortcomings: (1) Incomplete stress coverage: The existing schemes almost only use single / double stress tests of temperature or temperature + vibration, completely ignoring the coupling effect of electrical load and humidity, resulting in less than 60% consistency between the test failure mechanism and the actual vehicle failure. A large number of electrochemical migration and electromigration failures that occur in actual vehicles cannot be reproduced in the laboratory. (2) Insufficient model accuracy: There is a lack of multi-stress coupling conversion models adapted to complex vehicle electronic systems. Existing models mostly use simple stress superposition methods and do not consider the nonlinear interaction between stresses, resulting in extrapolation errors of more than 50% for long lifespans of more than 20 years, which cannot meet the verification requirements of the whole vehicle life cycle. (3) Incomplete failure identification: The single failure criterion of "complete loss of function" is commonly used, which cannot identify non-catastrophic failures such as performance degradation (such as decreased display frame rate and increased communication error rate) and functional limitation (such as failure of some modules). Such failures account for more than 80% of after-sales complaints in actual vehicles, resulting in life prediction results being seriously optimistic.

[0005] Therefore, developing an accelerated life testing method that can realistically reproduce multi-stress coupling failures in real vehicles, achieve accurate extrapolation for long lifespans, and cover all dimensions of failure modes has become a critical technological problem that urgently needs to be solved in the field of automotive electronics reliability. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a controller accelerated life test method based on multi-stress coupling.

[0007] The objective of this invention can be achieved through the following technical solution: a controller accelerated life testing method based on multi-stress coupling, comprising: A vehicle-mounted electronic controller sample was selected, and its performance was tested to determine the core failure mechanism and stress limit boundary. Based on the core failure mechanism, a life reduction model with multi-stress coupling is constructed. Set a cyclic test cycle, and design a cyclic accelerated test profile based on the stress limit boundary within the cyclic test cycle; The test condition parameters of the vehicle electronic controller sample are set according to the stress limit boundary. The vehicle electronic controller sample is placed in the cyclic acceleration test profile, and an accelerated life test is carried out based on the test condition parameters. The failure state of the vehicle electronic controller sample is determined based on the multi-level failure criteria set according to the core failure mechanism. The lifetime calculation model is solved using the failure data corresponding to the failure state. The target operating condition parameters are input into the solved life conversion model, and the corresponding actual service life is calculated according to the preset reliability target.

[0008] As an optional embodiment of the present invention, performance testing is performed on the vehicle-mounted electronic controller sample to determine the core failure mechanism and stress limit boundary, including: The on-board electronic controller sample was subjected to full performance testing under preset standard operating conditions, and the baseline values ​​of the core parameters were initially calibrated. The vehicle electronic controller sample was subjected to a step stress pre-test until the vehicle electronic controller sample failed. Based on the baseline values ​​of the core parameters, failure analysis is performed on the failure data of the vehicle electronic controller sample to determine the core failure mechanism and stress limit boundary.

[0009] As an optional embodiment of the present invention, a multi-stress coupled lifetime calculation model is constructed based on the core failure mechanism, including: The mapping relationship between temperature stress and thermal aging failure in the core failure mechanism is established based on the Arrhenius model. The mapping relationship between temperature and humidity coupled stress and electrochemical migration failure in the core failure mechanism was established based on the Peck model. The mapping relationship between vibration stress and weld fatigue failure in the core failure mechanism is established based on the inverse power law model. Based on the Alling model, a mapping relationship between electrical load stress and electromigration failure is established in the core failure mechanism; By coupling the various mapping relationships, a life calculation model covering the four-dimensional stress coupling of temperature, humidity, vibration, and electrical load is obtained.

[0010] As an optional embodiment of the present invention, the cyclic acceleration test profile includes at least one or more combinations of the following: low temperature static test profile, low temperature cold start test profile, gradual temperature increase driving test profile, high temperature and high humidity load test profile, gradual temperature decrease driving test profile, normal temperature driving test profile, and normal temperature static test profile. The total duration of the cyclic accelerated test profile is one cyclic test cycle.

[0011] As an optional embodiment of the present invention, the failure state of the vehicle electronic controller sample is determined according to a multi-level failure criterion based on the core failure mechanism, including: The failure states include full-function failure, functional limitation failure, and performance degradation failure; The functional characteristic data of the vehicle electronic controller sample are continuously monitored during the test, and the failure status of the vehicle electronic controller sample is determined based on the functional characteristic data and the multi-level failure criteria.

[0012] As an optional embodiment of the present invention, the lifetime calculation model is solved using the failure data corresponding to the failure state, including: When the vehicle electronic controller sample is determined to be a fully functional failure, the failure data corresponding to the fully functional failure is fitted using a two-parameter Weibull distribution to obtain the test characteristic lifetime. The test characteristic lifetime and the test condition parameters are input into the lifetime conversion model, and the maximum likelihood estimation algorithm is used to solve for the test parameters of the lifetime conversion model.

[0013] As an optional embodiment of the present invention, the target operating condition parameters are input into the solved life conversion model, and the corresponding actual service life is calculated according to the preset reliability target, including: The target operating condition parameters of the sample to be tested are input into the solved life conversion model to obtain the corresponding characteristic life. Substituting the characteristic lifetime into the reliability calculation formula, the actual service life corresponding to the target operating condition parameters is calculated based on the preset reliability target.

[0014] As an optional embodiment of the present invention, it further includes life verification of the actual service life; The life verification process includes calculating the acceleration factor between the target operating condition parameters and the operating condition parameters used for accelerated testing, based on the solved life conversion model. Based on the acceleration factor, the theoretical accelerated test duration equivalent to the preset actual service life target is calculated; The test sample is subjected to accelerated life test based on the accelerated test conditions parameters. If the test sample continues to run for a duration greater than or equal to the theoretical accelerated test duration and no failure state is determined, then the test sample is determined to meet the preset actual service life target.

[0015] This invention also proposes a controller accelerated life testing device based on multi-stress coupling, comprising: The performance testing module is used to select vehicle electronic controller samples, perform performance tests on the vehicle electronic controller samples, and determine the core failure mechanism and stress limit boundary. The model building module is used to construct a multi-stress coupling lifetime reduction model based on the core failure mechanism. The test profile design module is used to set the cyclic test cycle and design the cyclic accelerated test profile according to the stress limit boundary within the cyclic test cycle. The accelerated testing module is used to set the test condition parameters of the vehicle electronic controller sample according to the stress limit boundary, place the vehicle electronic controller sample in the cyclic accelerated test profile, and conduct accelerated life test based on the test condition parameters. The failure determination module is used to determine the failure state of the vehicle electronic controller sample based on the multi-level failure criteria set according to the core failure mechanism. The model solving module is used to solve the lifetime calculation model using the failure data corresponding to the failure state; The life calculation module is used to input the target operating condition parameters into the solved life conversion model and calculate the corresponding actual service life according to the preset reliability target.

[0016] The present invention also provides an electronic device, comprising: processor; Memory used to store processor-executable instructions; The processor is configured to implement the aforementioned controller accelerated life test method based on multi-stress coupling when executing executable instructions.

[0017] Compared with the prior art, the present invention has the following significant technical effects: (1) The core failure mechanism and stress limit boundary were accurately calibrated by step stress pre-experiment, which ensured the consistency between the accelerated life test process and the failure physics of the actual vehicle, and effectively avoided the risk of non-natural failure caused by stress overload. (2) By constructing a multi-stress coupled life conversion model, nonlinear cross-coupling terms of temperature-vibration and temperature-humidity-electric stress are introduced, which solves the problem of large extrapolation error of long life in traditional models and controls the prediction error of life of more than 20 years to within 5%. (3) Matching dynamic cyclic accelerated test profile breaks the limitations of traditional single or dual stress test, and can truly restore the aging process of vehicle electronic controller under extremely complex temperature, humidity, mechanical vibration and electrical load coupling, significantly shortening the test cycle for verifying 20 to 30 years of service life. (4) A three-level failure criterion covering multiple dimensions such as full-function failure, functional limitation and performance degradation is introduced, which fully covers all failure modes of real vehicles and realizes the quantitative mapping from multi-dimensional failure data in the laboratory environment to the actual life under the target working condition. This solves the problems of low life prediction accuracy of complex vehicle electronic systems such as intelligent cockpits throughout the entire life cycle and the omission of non-catastrophic failures by traditional single criteria, and greatly reduces after-sales quality risks. Attached Figure Description

[0018] Figure 1 This is a flowchart of the accelerated life test method for controllers based on multi-stress coupling according to an embodiment of the present invention; Figure 2 This is a timing diagram of the 24-hour cyclic accelerated test profile according to an embodiment of the present invention; Figure 3 This is a block diagram of a controller-based accelerated life testing device according to an embodiment of the present invention. Detailed Implementation

[0019] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0020] Example 1

[0021] Based on the technical problems highlighted in the background, this embodiment proposes an accelerated life testing method for controllers based on multi-stress coupling, such as... Figure 1 As shown, it includes: S1. Select an on-board electronic controller sample, perform performance tests on the on-board electronic controller sample, and determine the core failure mechanism and stress limit boundary. S2, Based on the core failure mechanism, construct a life calculation model with multi-stress coupling; S3, Set the cyclic test cycle, and design the cyclic accelerated test profile according to the stress limit boundary within the cyclic test cycle; S4. Set the test condition parameters of the vehicle electronic controller sample according to the stress limit boundary, place the vehicle electronic controller sample in the cyclic acceleration test profile, and conduct accelerated life test based on the test condition parameters. S5. Determine the failure state of the vehicle electronic controller sample based on the multi-level failure criteria set according to the core failure mechanism. S6, Solve the lifetime calculation model using the failure data corresponding to the failure state; S7. Input the target operating condition parameters into the solved service life conversion model, and convert the output results into actual service life according to the reliability calculation formula.

[0022] This method is applicable to vehicle electronic controllers, especially smart cockpit domain controllers. This embodiment will take the smart cockpit domain controller (hereinafter referred to as the controller) as an example to illustrate the specific implementation process in detail.

[0023] To establish a life conversion model suitable for multi-stress coupling controllers, this embodiment selects 14 controllers from the same batch and those that have passed factory inspection, all mass-produced and installed by major domestic vehicle manufacturers, as test samples. Of these, 12 samples were used for formal accelerated life testing, and 2 were used for step stress pre-testing. Before the accelerated life test, performance tests were conducted on the test samples. All test samples underwent initial full-item performance testing. After full-item performance testing, the two test samples underwent step stress pre-testing to determine the core failure mechanism and stress limit boundary of each controller. The core failure mechanism serves as the basis for constructing the life conversion model for multi-stress coupling, while the stress limit boundary is used to design a cyclic accelerated test profile and test condition parameters for the controller that closely match actual vehicle operating conditions.

[0024] The controllers are installed on the vibration table fixture inside the multi-stress integrated test chamber, replicating the actual vehicle installation state. Power supply, communication, and signal acquisition lines are connected, and equipment linkage debugging is performed. Within the test chamber, through synchronous linkage control of the multi-stress equipment, a cyclic accelerated test profile of four-dimensional stress coupling (temperature, humidity, vibration, and electrical load) can be automatically applied. According to the designed cyclic accelerated test profile and the test condition parameters of each controller, each controller initiates an accelerated life test. During the test, functional characteristic data of the controllers are collected in real time. Based on multi-level failure criteria pre-set according to the core failure mechanism, real-time failure determination is performed on the controllers, triggering audible and visual warnings and emergency shutdown protection. Based on the determined failure state, corresponding failure data, including failure time, failure mode, and failure stress limit, are recorded. The parameters within the life conversion model are solved using the failure data of multiple controllers, and the model's fitting effect is verified. Based on the solved model parameters, the acceleration factor of each controller under normal vehicle operating conditions can be calculated, representing the conversion relationship between the controller's accelerated life test time and its actual service life under normal vehicle operating conditions. For the new controller, the target operating condition parameters can be input into the life conversion model. Based on the model output and the preset reliability target, the corresponding actual service life can be calculated. The accuracy of the actual service life can be verified through accelerated life testing.

[0025] This method takes "consistency of failure mechanism" as the fundamental premise, accurately calibrates the core failure mechanism and stress limit through performance testing, constructs a four-stress life conversion model including nonlinear cross-coupling terms, designs a cyclic acceleration test profile that replicates the full working conditions of the real vehicle, establishes a multi-level failure criterion covering all dimensions of failure, and achieves accurate mapping from laboratory accelerated life test data to the full life cycle of the real vehicle.

[0026] Preferably, the on-board electronic controller sample undergoes performance testing to determine the core failure mechanism and stress limit boundary, including: The on-board electronic controller sample was subjected to full performance testing under preset standard operating conditions, and the baseline values ​​of the core parameters were initially calibrated. The vehicle electronic controller sample was subjected to a step stress pre-test until the vehicle electronic controller sample failed. Based on the baseline values ​​of the core parameters, failure analysis is performed on the failure data of the vehicle electronic controller sample to determine the core failure mechanism and stress limit boundary.

[0027] Performance testing includes initial full-item performance testing and step stress pre-testing. The purpose of initial full-item performance testing is to initially calibrate the baseline values ​​of core parameters, while the purpose of step stress pre-testing is to determine the stress limit boundary.

[0028] Before conducting the initial full-item performance test, a standard operating condition is preset. In this embodiment, the standard operating condition is a normal temperature and pressure environment with a temperature of 25℃±2℃ and a relative humidity of 45%±5%. It can be understood that the standard operating condition can be set according to the actual situation. Under this normal temperature and pressure environment, the initial full-item performance test is performed on all controllers, and the baseline values ​​of core parameters such as cold start time, display frame rate, audio and video synchronization error, CAN FD bus communication bit error rate, and total power consumption are recorded and calibrated as the basis for subsequent failure state determination.

[0029] After initial full-performance testing, two selected test samples were installed on a vibration table fixture within a multi-stress integrated test chamber, replicating the actual vehicle installation state. Power supply, communication, and signal acquisition circuit connections were completed. A step-stress pre-test was conducted, gradually increasing the stress level in increments of 10°C for temperature, 10%RH for humidity, 2g for vibration, and 1V for voltage, maintaining each step for two hours, monitoring the controller until full-function failure. Failure analysis was performed on the failed samples based on the baseline values ​​of core parameters and the values ​​after full-function failure. Metallographic sections revealed fatigue cracks in the solder joints, and scanning electron microscopy and energy dispersive spectroscopy detected electrochemical migration dendrites and thermal aging traces on the PCB surface. The core failure mechanism of the controller was determined to be semiconductor thermal aging, electrochemical migration induced by temperature and humidity coupling, fatigue cracking of the solder joints caused by vibration, and electromigration failure caused by electrical load, which is completely consistent with failure reports from the actual vehicle market.

[0030] Based on the results of the step stress pre-test, the stress limit boundary of the controller without changing the core failure mechanism is determined to be: temperature -40℃~105℃, humidity ≤95%RH, total root mean square acceleration of random vibration ≤15g, power supply voltage 9V~16V, and load rate 0~100%.

[0031] Preferably, based on the core failure mechanism, a multi-stress coupling lifetime reduction model is constructed, including: The mapping relationship between temperature stress and thermal aging failure in the core failure mechanism is established based on the Arrhenius model. The mapping relationship between temperature and humidity coupled stress and electrochemical migration failure in the core failure mechanism was established based on the Peck model. The mapping relationship between vibration stress and weld fatigue failure in the core failure mechanism is established based on the inverse power law model. Based on the Alling model, a mapping relationship between electrical load stress and electromigration failure is established in the core failure mechanism; By coupling the various mapping relationships, a life calculation model covering the four-dimensional stress coupling of temperature, humidity, vibration, and electrical load is obtained.

[0032] This embodiment proposes a mapping relationship between stress and the core failure mechanism based on the four core failure mechanisms identified in the step stress pre-test. Specifically: Based on the Arrhenius model, the mapping relationship between temperature stress and thermal aging failure in the core failure mechanism is established:

[0033] Based on the Peck model, the mapping relationship between temperature and humidity coupled stress and electrochemical migration failure in the core failure mechanism is established:

[0034] Based on the inverse power law model, the mapping relationship between vibration stress and weld fatigue failure in the core failure mechanism is established:

[0035] Based on the Eyeing model, establish the mapping relationship between electrical load stress and electromigration failure in the core failure mechanism:

[0036] Introducing temperature-vibration coupling coefficient Coupling coefficient with temperature, humidity and electrical stress This characterizes the nonlinear synergistic acceleration effect between stresses. Coupled with the above mapping relationships, a life reduction model based on the four-stress coupling of temperature, humidity, vibration, and electrical load is obtained, and its expression is as follows:

[0037] In the formula: This refers to the characteristic lifespan of the controller under the corresponding operating parameters. These are the synthesis constants of the coupled model; The activation energy corresponding to the failure mechanism; Here is the Boltzmann constant, with a value of 8.617 × 10⁻⁶. −5 eV / K; Thermodynamic temperature; Relative humidity; Humidity impact index; This represents the effective value of random vibration acceleration. The vibration impact index; This is the comprehensive coefficient for electrical load; The coefficient representing the influence of electrical stress; This is the temperature-vibration coupling coefficient; This is the temperature, humidity, and electrical stress coupling coefficient.

[0038] Preferably, the cyclic acceleration test profile includes at least one or more combinations of the following: low temperature static test profile, low temperature cold start test profile, gradual temperature increase driving test profile, high temperature and high humidity load test profile, gradual temperature decrease driving test profile, normal temperature driving test profile, and normal temperature static test profile. The total duration of the cyclic accelerated test profile is one cyclic test cycle.

[0039] After constructing the model, the model parameters are solved using the results of accelerated life testing. Before the accelerated life test, various cyclic accelerated test profiles are designed. In this embodiment, the cyclic accelerated test profiles include a low-temperature static test profile, a low-temperature cold start test profile, a gradually increasing temperature driving test profile, a high-temperature and high-humidity load test profile, a gradually decreasing temperature driving test profile, a normal temperature driving test profile, and a normal temperature static test profile. In practice, the test profiles can be freely combined according to the cyclic test cycle. However, it should be noted that the total duration of the combined test profiles should be one cyclic test cycle. The stress parameters corresponding to each test profile can be adjusted according to the actual test conditions. This embodiment uses 24 hours as one cyclic test cycle, which includes all the above-mentioned cyclic accelerated test profiles. Specifically, as shown... Figure 2 As shown, the low-temperature static test profile lasted for two hours, with the temperature linearly decreasing from 25°C to -40°C. There was no humidity control, no vibration, and the controller was not powered on and was in a non-working state. This test profile reproduced the working conditions of vehicles being parked outdoors for a long time at night in cold regions during winter.

[0040] The low-temperature cold start test profile lasted for two hours, with the temperature maintained at -40℃, no humidity control, no vibration, and the controller operating at the rated voltage of 13.5V under no-load. This test profile reproduces the cold start conditions of the vehicle under extreme low temperatures.

[0041] The gradual temperature rise driving test profile lasted for two hours, with the temperature rising linearly from -40℃ to 85℃, humidity at 90%RH, vibration load rising linearly from 0g to 15g, and electrical load rising from no load to 100% full load. This test profile reproduces the alternating driving temperature rise conditions of the vehicle after starting from a low temperature environment, including rapid temperature rise of the engine and other power compartments, changes in ambient humidity, gradual increase in road vibration, and gradual increase in controller load.

[0042] The high temperature and high humidity load test profile lasted for eight hours, with the temperature maintained at 85℃, the humidity maintained at 90%RH, the vibration load maintained at 15g, and the electrical load maintained at 100% full load. This test profile reproduces the extreme high load conditions under summer high temperature and high humidity environment, where the vehicle is continuously driving at high speed, and the engine and other power compartments are operating at high temperature and high humidity, and the controller is running at full load for a long time.

[0043] The gradual cooling driving test profile lasted for two hours. The temperature dropped linearly from 85℃ to 25℃, the humidity dropped to 60%RH, the vibration load dropped linearly from 15g to 10g, and the electrical load dropped from full load to 50%. This test profile reproduced the alternating driving cooling conditions of the vehicle from a high temperature and high load driving state to a normal temperature environment, stopping to cool down, road vibration reduced, and controller load gradually reduced.

[0044] The normal temperature driving test profile lasts for six hours, with the temperature maintained at 25°C, the humidity reduced to 45%RH, the vibration load maintained at 10g, and the electrical load cyclically alternating from 30% to 80% of the full load. This test profile reproduces the daily driving conditions of the vehicle in urban and suburban areas under normal temperature conditions.

[0045] The static test profile at room temperature lasted for two hours, with the temperature maintained at 25℃ and the humidity at 45%RH. There was no vibration, and the controller was not powered on and was in a non-working state. This test profile reproduced the parking conditions where the vehicle was parked in the garage, the engine was turned off and the power was cut off, and the controller was completely shut down and left to stand still.

[0046] Different test parameters were set for 12 controllers to conduct accelerated life tests on a cyclic accelerated test profile. In this embodiment, after full performance testing, to ensure the statistical significance of the test results, the 12 controllers were divided into 4 groups of 3 controllers each. The test parameters for each group were different, representing different accelerated test stress levels. The specific settings are shown in the table below: Table 1. Stress level settings for each group of accelerated tests

[0047] Each controller group is installed in a multi-stress integrated test chamber to restore the actual vehicle installation state. All wiring connections and equipment linkage debugging are completed. The low temperature static test profile, low temperature cold start test profile, gradual temperature increase driving test profile, high temperature and high humidity load test profile, gradual temperature decrease driving test profile, normal temperature driving test profile, and normal temperature static test profile are automatically loaded in sequence. Accelerated life test is carried out according to the corresponding test condition parameters of each group.

[0048] Preferably, the failure state of the vehicle electronic controller sample is determined according to a multi-level failure criterion based on the core failure mechanism, including: The failure states include full-function failure, functional limitation failure, and performance degradation failure; The functional characteristic data of the vehicle electronic controller sample are continuously monitored during the test, and the failure status of the vehicle electronic controller sample is determined based on the functional characteristic data and the multi-level failure criteria.

[0049] This embodiment establishes multi-level failure criteria based on the controller's comprehensive performance test results and automotive-grade standards. These criteria include Level 1 fatal failure, Level 2 severe failure, and Level 3 minor failure, with each level corresponding to a specific failure state. Failure states include full-function failure, functional limitation failure, and performance degradation failure. By establishing multi-level failure criteria, the system comprehensively covers real-world fatal, severe, and minor failures, overcoming the shortcomings of existing technologies that only focus on functional failures and ignore performance degradation. This enables comprehensive monitoring of the lifespan degradation of automotive electronic controllers.

[0050] In this embodiment, the first-level fatal failure corresponds to a full-function failure. The criteria for a full-function failure are that the controller cannot be powered on and started, the core functions are completely lost, the bus communication is interrupted, or there is a short circuit, smoke, or fire. Once the failure is determined, the controller test is terminated immediately.

[0051] A Level 2 severe failure is less severe than a Level 1 fatal failure. A Level 2 severe failure corresponds to a functional limitation failure. The criteria for a functional limitation failure are: controller cold start time exceeding a baseline value by 200%, display frame rate drop exceeding 30%, audio / video synchronization error exceeding 50ms, and CAN FD bus bit error rate exceeding 10%. -6 If the power consumption exceeds 50% of the rated value and cannot be reset for 5 seconds, the controller is deemed to be faulty.

[0052] The severity of a Level 3 minor failure is less than that of a Level 2 severe failure. A Level 3 minor failure corresponds to a performance degradation failure. The criteria for a performance degradation failure are the loss of non-core functions of the controller and a slight degradation in performance, which can be recovered by resetting. If the cumulative number of occurrences exceeds a preset number (10 times in this embodiment), the controller is determined to have failed.

[0053] During the test, the host computer collects functional characteristic data of the controller in real time, such as cold start time, display frame rate, audio and video synchronization error, bus bit error rate, and power consumption. These data are compared with the benchmark values ​​of the core parameters, and real-time failure judgment is performed according to the pre-set three-level failure criteria to determine the failure state of the controller.

[0054] Preferably, the lifetime calculation model is solved using the failure data corresponding to the failure state, including: When the vehicle electronic controller sample is determined to be a fully functional failure, the failure data corresponding to the fully functional failure is fitted using a two-parameter Weibull distribution to obtain the test characteristic lifetime. The test characteristic lifetime and the test condition parameters are input into the lifetime conversion model, and the maximum likelihood estimation algorithm is used to solve for the test parameters of the lifetime conversion model.

[0055] In accelerated cyclic testing, the controller's core functions gradually fail. Generally, performance degradation corresponding to Level 3 minor failure occurs first. As the test duration increases, functional limitations corresponding to Level 2 severe failure appear, and finally, full-function failure corresponding to Level 1 fatal failure occurs. During the test, failure data for each level of failure is recorded. For example, the failure time, failure mode, and failure stress limit are recorded when the controller is determined to have a Level 3 minor failure. The failure time refers to the controller's continuous operating time from the start of the test when it is determined to have a Level 3 minor failure. For example, a failure time of 120 hours means the controller was determined to have a Level 3 minor failure after 120 hours of accelerated life testing. Failure modes include semiconductor device thermal aging, electrochemical migration caused by temperature and humidity coupling, fatigue cracking of solder joints caused by vibration, and electromigration failure caused by electrical loads. The failure stress limit refers to the stress level of temperature, humidity, vibration, and electrical loads in the accelerated cyclic test profile when the controller is determined to have a Level 3 minor failure. This stress level is the stress limit boundary at which the controller is determined to have a Level 3 minor failure after 120 hours of continuous operation.

[0056] The controller can continue to operate until it is determined to be a Level 2 severe failure, and the failure time, failure mode, and failure stress limit when the controller is determined to be a Level 2 severe failure are recorded. After the controller is determined to be a Level 2 severe failure, it can continue to operate until it is determined to be a Level 1 fatal failure, and the failure time, failure mode, and failure stress limit when the controller is determined to be a Level 1 fatal failure are recorded. Since a Level 1 fatal failure indicates a complete functional failure, the test must be terminated immediately.

[0057] Because the test profile undergoes cyclical changes, simulating drastic changes in real-world vehicle operating conditions, some controllers, due to performance differences, may sequentially determine Level 3 minor failure and Level 2 severe failure, or they may only determine Level 3 minor failure or Level 2 severe failure, but they will definitely determine Level 1 fatal failure. Therefore, this embodiment uses the failure data corresponding to when the controller determines a Level 1 fatal failure and performs a two-parameter Weibull distribution fitting to obtain the test characteristic lifetime. If the controller is determined to have a Level 3 minor failure and / or a Level 2 severe failure, the corresponding failure data can be used to evaluate the performance change trend of the controller.

[0058] The table below shows the failure time of each controller as a Level 1 fatal failure in this embodiment, and the cumulative failure probability calculated by sorting the failure times of each group from smallest to largest using the median rank method. Using the median rank method (average rank method) can avoid the systematic bias of directly using failure time to calculate the cumulative failure probability in small sample conditions.

[0059] Table 2 Statistical results of full-function failure time and cumulative failure probability of each group of controllers

[0060] The failure time and cumulative failure probability of each group were fitted using a two-parameter Weibull distribution, and the distribution function is:

[0061] In the formula: This represents the cumulative failure probability. Expiration time; For shape parameters; The characteristic lifetime is used. Linear fitting is performed using the least squares method to obtain the shape parameters of each controller group. With characteristic lifetime As shown in the table below: Table 3. Results of fitting parameters for the two-parameter Weibull distribution.

[0062] Shape parameters of each group of controllers All were between 3.2 and 3.8. A value greater than 1 indicates that the controller is in the wear-out failure stage, meeting the requirements of accelerated testing. (Fit correlation coefficient) All values ​​are greater than 0.98, indicating that the Weibull distribution fits the failure data well. As a core evaluation indicator, it can be derived based on the Pearson linear correlation coefficient R. The value range is [0, 1]. The closer the value is to 1, the better the linear fit. The two-parameter Weibull distribution fits the failure data better and the fitting result has high confidence.

[0063] The characteristic lifetime of each group of controllers is the test characteristic lifetime. The test characteristic lifetime of each controller group and the test condition parameters corresponding to the controller are substituted into the four-stress coupled lifetime conversion model. Combining the failure time of the controller and the two-parameter Weibull distribution characteristics, a maximum likelihood function is constructed. By maximizing the likelihood function value, the global optimal solution of the core parameters of the model is obtained. This method can make full use of the full sample failure data and has higher parameter estimation accuracy than the least squares method. It is especially suitable for small sample and multi-parameter solution scenarios of multi-stress coupled lifetime accelerated test.

[0064] Through iterative solving using the maximum likelihood estimation algorithm, the optimal estimates of the core parameters of the multi-stress coupled lifetime reduction model are obtained as follows: Activation Energy Humidity impact index Vibration Influence Index Electrical stress influence coefficient Temperature-vibration coupling coefficient Temperature and humidity-electric stress coupling coefficient .

[0065] To verify whether the constructed multi-stress coupling lifetime reduction model has statistical significance, that is, whether all stress terms and coupling terms together have a significant linear explanatory power for the experimental characteristic lifetime, this embodiment uses the multivariate linear regression overall significance F test to verify the statistical significance of the model.

[0066] The calculated F-test p-value is <0.001, indicating that the model is highly significant at the 99.9% confidence level and there is no spurious regression problem; the model fit is good. It can explain 99.2% of the experimental characteristic lifetime variation and has excellent fitting effect.

[0067] Preferably, the target operating condition parameters are input into the solved service life conversion model, and the corresponding actual service life is calculated according to the preset reliability target, including: The target operating condition parameters of the sample to be tested are input into the solved life conversion model to obtain the corresponding characteristic life. Substituting the characteristic lifetime into the reliability calculation formula, the actual service life corresponding to the target operating condition parameters is calculated based on the preset reliability target.

[0068] The test sample is an on-board electronic controller. The controller's normal operating conditions in a real vehicle are used as target operating conditions and substituted into the solved and verified life conversion model. For example, the normal operating conditions in a real vehicle are: temperature 25℃, humidity 45% RH, vibration 0.1g, electrical load 13.5V / 30%, and the corresponding characteristic life. Approximately 19.2 years. According to the reliability calculation formula:

[0069] Shape parameters here , where is the average value of each group of controllers. Based on the above formula, the actual service life under different reliability targets is calculated.

[0070] When the reliability target R=50% (median life), the actual service life is about 9.58 years, which meets the vehicle's 10-year / 240,000-kilometer warranty requirement.

[0071] When the reliability R=90% (B10 life), the actual service life is about 26 years, which meets the full life cycle requirement of 20 to 30 years for the whole vehicle.

[0072] Preferably, the method further includes life verification of the actual service life; The life verification process includes calculating the acceleration factor between the target operating condition parameters and the operating condition parameters used for accelerated testing, based on the solved life conversion model. Based on the acceleration factor, the theoretical accelerated test duration equivalent to the preset actual service life target is calculated; The test sample is subjected to accelerated life test based on the accelerated test conditions parameters. If the test sample continues to run for a duration greater than or equal to the theoretical accelerated test duration and no failure state is determined, then the test sample is determined to meet the preset actual service life target.

[0073] To verify the actual service life, calculate the acceleration factor of the real vehicle under normal operating conditions relative to the L1 group test conditions:

[0074] One hour under the L1 test conditions is equivalent to 218 hours under normal operating conditions in a real vehicle. To verify the 20-year lifespan of the entire vehicle (approximately 175,200 hours), the equivalent theoretical acceleration test duration is approximately 175,200 / 218 ≈ 804 hours (approximately 34 days).

[0075] Three test samples from the same batch were placed under the L1 test conditions for accelerated life testing. If all samples ran continuously for more than 804 hours without any full-function failure, the batch of controllers was deemed to meet the 20-year full life cycle requirement.

[0076] Comparative verification shows that the actual service life prediction results of this method have an error of 3.2% compared with the actual vehicle road test data over 3 years, while the prediction error of the traditional temperature + vibration dual stress model is 47.8%, improving the accuracy by more than 14 times; the verification of 20-year service life takes only 35 days, which is more than 75% shorter than the traditional method.

[0077] This method has the following significant technical advantages: (1) By accurately calibrating the core failure mechanism and stress limit boundary through step stress pre-experiment, the consistency between the accelerated life test process and the actual vehicle failure physics is ensured, and the risk of non-natural failure caused by stress overload is effectively avoided.

[0078] (2) By constructing a multi-stress coupled life conversion model, nonlinear cross-coupling terms of temperature-vibration and temperature-humidity-electric stress are introduced, which solves the problem of large extrapolation error of long life in traditional models and controls the prediction error of life of more than 20 years to within 5%.

[0079] (3) Matching dynamic cyclic accelerated test profile breaks the limitations of traditional single or dual stress test, and can truly restore the aging process of vehicle electronic controller under extremely complex temperature, humidity, mechanical vibration and electrical load coupling, significantly shortening the experimental cycle for verifying 20 to 30 years of service life.

[0080] (4) A three-level failure criterion covering multiple dimensions such as full-function failure, functional limitation and performance degradation is introduced, which fully covers all failure modes of real vehicles and realizes the quantitative mapping from multi-dimensional failure data in the laboratory environment to the actual life under the target working condition. This solves the problems of low life prediction accuracy of complex vehicle electronic systems such as intelligent cockpits throughout the entire life cycle and the omission of non-catastrophic failures by traditional single criteria, and greatly reduces after-sales quality risks.

[0081] Example 2 Based on the principles described in Embodiment 1, a controller-based accelerated life testing device 100 based on multi-stress coupling is also proposed, such as... Figure 3 As shown, it includes: Performance testing module 110 is used to select vehicle electronic controller samples, perform performance tests on the vehicle electronic controller samples, and determine the core failure mechanism and stress limit boundary. The model building module 120 is used to build a multi-stress coupling lifetime reduction model based on the core failure mechanism. The test profile design module 130 is used to set the cyclic test cycle and design the cyclic accelerated test profile according to the stress limit boundary within the cyclic test cycle. The accelerated testing module 140 is used to set the test condition parameters of the vehicle electronic controller sample according to the stress limit boundary, place the vehicle electronic controller sample in the cyclic accelerated testing profile, and conduct accelerated life test based on the test condition parameters. The failure determination module 150 is used to determine the failure state of the vehicle electronic controller sample according to the multi-level failure criteria set based on the core failure mechanism. Model solving module 160 is used to solve the lifetime calculation model using the failure data corresponding to the failure state; The life calculation module 170 is used to input the target operating condition parameters into the solved life conversion model and convert the output results into actual service life according to the reliability calculation formula.

[0082] Example 3 Furthermore, an electronic device is proposed, comprising: processor; Memory used to store processor-executable instructions; The processor is configured to implement a controller accelerated life test method based on multi-stress coupling in Embodiment 1 when executing executable instructions.

[0083] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0084] Furthermore, it should be noted that the use of terms such as "first," "second," and "a" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. The terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly specified. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0085] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0086] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A method for accelerated life testing of a controller based on multi-stress coupling, characterized in that, include: A vehicle-mounted electronic controller sample was selected, and its performance was tested to determine the core failure mechanism and stress limit boundary. Based on the core failure mechanism, a life reduction model with multi-stress coupling is constructed. Set a cyclic test cycle, and design a cyclic accelerated test profile based on the stress limit boundary within the cyclic test cycle; The test condition parameters of the vehicle electronic controller sample are set according to the stress limit boundary. The vehicle electronic controller sample is placed in the cyclic acceleration test profile, and an accelerated life test is carried out based on the test condition parameters. The failure state of the vehicle electronic controller sample is determined based on the multi-level failure criteria set according to the core failure mechanism. The lifetime calculation model is solved using the failure data corresponding to the failure state. The target operating condition parameters are input into the solved life conversion model, and the corresponding actual service life is calculated according to the preset reliability target.

2. The method according to claim 1, characterized in that, The vehicle-mounted electronic controller sample was subjected to performance testing to determine the core failure mechanism and stress limit boundary, including: The on-board electronic controller sample was subjected to full performance testing under preset standard operating conditions, and the baseline values ​​of the core parameters were initially calibrated. The vehicle electronic controller sample was subjected to a step stress pre-test until the vehicle electronic controller sample failed. Based on the baseline values ​​of the core parameters, failure analysis is performed on the failure data of the vehicle electronic controller sample to determine the core failure mechanism and stress limit boundary.

3. The method according to claim 1, characterized in that, Based on the core failure mechanism, a multi-stress coupled lifetime reduction model is constructed, including: The mapping relationship between temperature stress and thermal aging failure in the core failure mechanism is established based on the Arrhenius model. The mapping relationship between temperature and humidity coupled stress and electrochemical migration failure in the core failure mechanism was established based on the Peck model. The mapping relationship between vibration stress and weld fatigue failure in the core failure mechanism is established based on the inverse power law model. Based on the Alling model, a mapping relationship between electrical load stress and electromigration failure is established in the core failure mechanism; By coupling the various mapping relationships, a life calculation model covering the four-dimensional stress coupling of temperature, humidity, vibration, and electrical load is obtained.

4. The method according to claim 1, characterized in that, The cyclic acceleration test profile includes at least one or more combinations of the following: low temperature static test profile, low temperature cold start test profile, gradual temperature increase driving test profile, high temperature and high humidity load test profile, gradual temperature decrease driving test profile, normal temperature driving test profile, and normal temperature static test profile. The total duration of the cyclic accelerated test profile is one cyclic test cycle.

5. The method according to claim 1, characterized in that, The failure state of the vehicle electronic controller sample is determined based on a multi-level failure criterion established according to the core failure mechanism, including: The failure states include full-function failure, functional limitation failure, and performance degradation failure; The functional characteristic data of the vehicle electronic controller sample are continuously monitored during the test, and the failure status of the vehicle electronic controller sample is determined based on the functional characteristic data and the multi-level failure criteria.

6. The method according to claim 5, characterized in that, Solving the lifetime reduction model using the failure data corresponding to the failure state includes: When the vehicle electronic controller sample is determined to be a fully functional failure, the failure data corresponding to the fully functional failure is fitted using a two-parameter Weibull distribution to obtain the test characteristic lifetime. The test characteristic lifetime and the test condition parameters are input into the lifetime conversion model, and the maximum likelihood estimation algorithm is used to solve for the test parameters of the lifetime conversion model.

7. The method according to claim 1, characterized in that, The target operating condition parameters are input into the solved service life conversion model, and the corresponding actual service life is calculated according to the preset reliability target, including: The target operating condition parameters of the sample to be tested are input into the solved life conversion model to obtain the corresponding characteristic life. Substituting the characteristic lifetime into the reliability calculation formula, the actual service life corresponding to the target operating condition parameters is calculated based on the preset reliability target.

8. The method according to claim 7, characterized in that, It also includes life verification of the actual service life; The life verification process includes calculating the acceleration factor between the target operating condition parameters and the operating condition parameters used for accelerated testing, based on the solved life conversion model. Based on the acceleration factor, the theoretical accelerated test duration equivalent to the preset actual service life target is calculated; The test sample is subjected to accelerated life test based on the accelerated test conditions parameters. If the test sample continues to run for a duration greater than or equal to the theoretical accelerated test duration and no failure state is determined, then the test sample is determined to meet the preset actual service life target.

9. A controller-based accelerated life testing device based on multi-stress coupling, characterized in that, include: The performance testing module is used to select vehicle electronic controller samples, perform performance tests on the vehicle electronic controller samples, and determine the core failure mechanism and stress limit boundary. The model building module is used to construct a multi-stress coupling lifetime reduction model based on the core failure mechanism. The test profile design module is used to set the cyclic test cycle and design the cyclic accelerated test profile according to the stress limit boundary within the cyclic test cycle. The accelerated testing module is used to set the test condition parameters of the vehicle electronic controller sample according to the stress limit boundary, place the vehicle electronic controller sample in the cyclic accelerated test profile, and conduct accelerated life test based on the test condition parameters. The failure determination module is used to determine the failure state of the vehicle electronic controller sample based on the multi-level failure criteria set according to the core failure mechanism. The model solving module is used to solve the lifetime calculation model using the failure data corresponding to the failure state; The life calculation module is used to input the target operating condition parameters into the solved life conversion model and calculate the corresponding actual service life according to the preset reliability target.

10. An electronic device, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to implement the controller accelerated life test method based on multi-stress coupling as described in any one of claims 1-8 when executing executable instructions.

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