|Technologies for future distributed engine controls|
|Applied Vehicle Technology|
Control Systems, Distributed System Control Systems, Embedded Diagnostic and Prognostic Capabilities, Engine, FADEC, Gas Turbine, Integrated Air Vehicles, Testing, Turbine Engine Instrumentation
Current trends in military aviation greatly expand the use of highly integrated, increasingly autonomous air vehicles, with distributed control systems (DCS), especially in the area of engine optimization. In DCS each system element individually connects to the network and has multiple functions, some of which require real-time communication for control and others which may be less time critical. The weight of wiring and need for cooling are significantly reduced in the engine due to DCS when compared to the traditional centralized FADEC.
Distributed Engine Control using advanced sensing techniques, high temperature electronics and open data communication will reverse the growing trend of increasing ratio of control system weight to engine weight and also will be a major factor in decreasing overall cost of ownership. Challenges for implementation include need for validation of engine test cell proven sensing techniques, high temperature electronics (located on or close to the sensing element), development of simple, robust communications (simplifying and reducing the wiring harness), and power supply for the on-board distributed electronics. With the limitations of standard silicon technology for current smart sensors, newer material technologies such as Silicon On Insulator (SOI) and/or Silicon Carbide (SiC) electronics are required.
A distributed architecture also relies on efficient network communication to achieve good performance. Standardized network requirements, protocols, and interfaces are important for widespread adoption and future modifiability. Distributed turbine engine control architecture enables the use of advanced control algorithms along with achieving weight reduction, improvement in performance and lower life cycle cost. The performance of distributed engine control system is predominantly dependent on the performance of the communication bus. Communication network faults like limited bandwidth, transmission delays and data loss can limit or even degrade the performance of the distributed engine control system. What is required is to analyse and synthesize a robust distributed controller to guarantee desired engine performance under network faults for full envelope operation. Hence, the goal of the conducted research was to analyse and synthesize a robust distributed controller to guarantee desired engine performance under network faults for full envelope operation.
A number of advanced instrumentation technologies are currently used in different and also novel applications in the turbine engine test cell environment with high success, as summarized in two successful AVT activities, AVT-180 and AVT-229. These new measurement technologies are in various stages of development, but they offer an opportunity to provide information on different key parameters within the engine. A number of promising sensors for health management and active control of propulsion systems have been submitted for presentation at the AVT-306 Specialists Meeting. Although there are significant issues which must be addressed, many of these technologies could have the potential to provide valuable contributions to the safety, reliability, life cycle cost and performance of turbine engines operating in the field.
The development and implementation of the necessary hardware and software technologies to enable intelligent distributed engine control systems will also require a collaborative effort between the engine and air vehicle manufacturers in addressing the many technical issues and sorting out their respective control volumes within a relatively confined space.
This activity aims to identify and evaluate hardware and software technologies proven in the test cell environment which are needed to enable the transformation of turbine engine control systems from centralized to distributed architecture. Desired attributes include increased robustness, temperature resistance, improved accuracy, and the ability to operate effectively in the engine environment.
• Use and transition of test cell proven advanced measurement techniques
• Distributed intelligent Control Systems
• Robust, reliable diagnostic and prognostic systems for PHM and controls
• High temperature-compatible communication architectures
• Fiber-optic sensing, Fiber-Optic Engine Control Network, Fly by Light Systems
• Standardized smart sensors and actuators
• Standardized system infrastructure – software, power supplies, chips, communication hardware, testing & evaluation
• Certifiable components
• Integration testing