Reliability performance measure model and method for avionics
Abstract
Avionics required reliability is to be implemented at later stages of its lifecycle but its reliability is embedded during the design stage. Therefore, calculation and estimation of avionics reliability is a significant part of designing avionics. Predictive, structural or physical calculation methods are used for this purpose. However, the applied methods do not fully take into account physical operating conditions of devices, which reduces results’ accuracy and reliability of calculation and reliability assessment. This determines the relevance of research and testing of new models and evaluation methods. This research work is aimed at improving the assessment accuracy and reliability of spacecraft avionics performance. Microprocessor-based temperature controller was employed as research subject. Structural model was proposed to estimate spacecraft avionics performance reliability. Upon that, there was applied the procedure for breaking electrical circuit into "identical" parts as per conditions and operating time taking into account takeover indices, load capacity factors and diagnostic monitoring. This model-based new method is proposed for calculating and estimating performance reliability. Assessment is performed gradually in steps:
- preliminary calculation with regard to takeover indices and factor of organizational and technical measures at the particular enterprise;
- intermediate step is as per the results of separate or integrated tests to make it possible to consider individual prediction data;
- final step is as per results of flight tests.
Example of calculating the probability of failure-free operation of one channel of the device is given. The results of the calculation made it clear that the probability of failure-free operation of one channel of the device is 0.9701255 with specified probability of 0.96. Therefore, the device meets the requirements indicated in technical specifications for operational life and probability value of failure-free operation. The next stage of evaluation is based on the results of separate or integrated tests. The proposed model and method were tested at Rocket and Space Center “Progress” JSC.
