Full-Authority Fault-Tolerant Electronic Engine Control System for Variable Cycle Engines

摘要

The objective of this program was to develop a design approach for full-authority digital electronic control systems with reliability the primary consideration factor. The approach used in attacking this objective was to identify a baseline full-authority digital electronic control system for and advanced fighter aircraft and then improve on this baseline control with respect to specific goals using redundancy, recovery strategies, and maintenance philosophies. Ambitious goals were established for controls-related mission reliability (2.5 mission aborts per million operating hours), mean time between control removals (1800 hours), and fail operational capability. Candidate control designs were evaluated with respect to cost and weight in addition to their ability to satisfy the design goals. The baseline control system was modularized to yield identifiable components (pumps, thermocouples, actuators, etc.). For these components, reliability and cost information was accumulated. Many of these configurations were screened with a Markov-based constant failure rate analysis simulation called the Generalized Reliability and Maintainability Program (GRAMP). A Generalized Reliability and Maintainability Simulator (GRAMS) tested promising configurations from GRAMP, using a time-varying analysis approach based on Monte Carlo techniques. The results of the GRAMP and GRAMS analysis showed necessary cost and weight increases associated with achieving an order of magnitude improvement in mission reliability by using a fault-tolerant structure as opposed to the baseline system.