RESEARCH AND STUDY OF ANALYTICAL TECHNIQUES FOR PREDICTING RELIABILITY OF FLIGHT-CONTROL SYSTEMS

摘要

The objective of the project was to develop analytical techniques to predict the performance of flight-control components (mainly mechanical, electromechanical, and electrohydraulic) with respect to time, whereby an inference to their reliability could be made without resorting to life testing of the components themselves. Reliability is defined as the probability that a device will exhibit a required performance under a specific environment for a certain time interval. The method of analytical reliability prediction being developed at Battelle uses a model that relates performance aspects of a device to its input and internal parameters. From this model, partial derivatives of each performance aspect with respect to internal parameters are computed. A Propagation of Variance formula which utilizes the partial derivatives and values of parameter variance is used to compute the variance (an index of variability) of each aspect of device performance. A reliability estimate can then be obtained by comparing the expected range of variability with appropriate specification limits.