NEED FOR ROBUST SENSORS FOR INHERENTLY FAIL-SAFE GAS TURBINE ENGINE CONTROLS, MONITORING, AND PROGNOSTICS

摘要

Sensor reliability is critical to turbine engine control. Today's aircraft engines demand more sophisticated sensors in the control systems, requiring advanced engine testing for component performance demonstration. Expertise in the gas turbine instrumentation community is located across the gas turbine industry itself, within several specialized university departments serving to supplement the more general research programs in gas turbine research. Sensor technology has advanced in many fields; however, implementation has been slower in aerospace applications. Today's push for engine health management through adaptive control systems demands more robust instrumentation with inherently fail safe sensors. The future needs of the USAF require innovative reliable control architectures. These needs require new ideas for turbine engine controls, employing the next generation computing, communication hardware and advanced sensors. Turbine engine control research includes: implementation, control theory, algorithms, sensors and transducers. Separate feedback loops are used to control the fuel, compressor, and nozzle to provide the desired engine thrust. State-of-the-art controls act on sensed engine parameters which provide measurements at a fixed time interval The controller outputs adjust valves, , and actuators to maintain stable engine operation. Current digital controls are based on synchronous, clock-based systems that take digitized analog sensor inputs at an approximate rate of 30Hz.In current engine control methodology, all signals travel on dedicated lines. All sensors or signal loss requires substitution with an equivalent (redundant) signal from other sensors or virtual values. Loss of a parameter (total signal loss) may lead to control failure and potential engine shutdown. Control algorithms use look up tables with embedded program values. Present control algorithms do not incorporate health management decisions as part of their function. All sensor signals have a specific bandwidth and travel by wire (or wireless in the future) to the control (FADEC) to complete the control process. All faults in the control system must be resolved in real-time All transient faults, captured may be evaluated at a later time when the aircraft completes its mission. All critical sensors are redundant. However, there needs to be a more robust sensor fault detection technology to be incorporated with the turbine engine to achieve more robust control and reduce both NRE and support cost.