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Stability and Performance of Propulsion Control Systems with Distributed Control Architectures and Failures

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Stability and Performance of Propulsion Control Systems with Distributed Control Architectures and Failures STABILITY AND PERFORMANCE OF PROPULSION CONTROL SYSTEMS WITH DISTRIBUTED CONTROL ARCHITECTURES AND FAILURES DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Rohit K. Belapurkar, M.S. Graduate Program in Aeronautical and Astronautical Engineering The Ohio State University 2012 Dissertation Committee: Prof. Rama K. Yedavalli, Advisor Prof. Meyer Benzakein Prof. Krishnaswamy Srinivasan Copyright by Rohit K. Belapurkar 2012 ABSTRACT Future aircraft engine control systems will be based on a distributed architecture, in which, the sensors and actuators will be connected to the controller through an engine area network. Distributed engine control architecture enables the use of advanced control techniques 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 communication network. Due to serial data transmission, time delays are introduced between the sensor/actuator nodes and distributed controller. Although these random transmission time delays are less than the control system sampling time, they may degrade the performance of the control system or in worst case, may even destabilize the control system. Network faults may result in data dropouts, which may cause the time delays to exceed the control system sampling time. A comparison study was conducted for selection of a suitable engine area network. A set of guidelines are presented in this dissertation based on the comparison study. Three different architectures for turbine engine control system based on a distributed framework are presented. A partially distributed engine control system for a turbo-shaft engine is designed based on ARINC 825, a general standardization of Controller Area Network (CAN). The effect of the addition of an engine area network on the stability and ii performance of the proposed partially distributed engine control system is presented. Stability conditions are presented for the proposed control system with output feedback under the presence of network-induced time delay and random data loss due to transient sensor/actuator failure. A control design is proposed to stabilize the distributed turbine control system under these communication constraints. A fault tolerant control design is proposed to benefit from the additional system bandwidth and also from the broadcast feature of the data network. It is shown that a reconfigurable fault tolerant control design in which several control input values are transmitted and stored at the actuator can help to reduce the performance degradation in presence of node failures. It is also demonstrated that the best nominal performance of the distributed engine control system can be obtained by designing the control law based only on the network induced time delay. However, the performance of this optimum control design degrades in presence of sensor or actuator faults. A performance comparison is presented between zero-input, hold-input and reconfigurable data loss compensation strategy. It is shown that the optimum overall performance of the turbine engine control system based on a partially distributed architecture was obtained when the controller was designed based only on networked induced time delay with a reconfigurable data loss compensation strategy. A T-700 turbo- shaft engine model is used to simulate and validate the proposed control theory based on both single input and multiple-input multiple-output control design methodologies. iii Dedicated to my wife, parents and grandparents for their love and support iv ACKNOWLEDGMENTS I would like to express my sincere gratitude to my adviser, Dr. Rama K. Yedavalli, for his support and guidance during my Ph.D. research. He created an ideal environment which gave me freedom to explore new ideas and an opportunity to work on industry-relevant projects. I am grateful to Dr. Meyer Benzakein and Dr. Krishnaswamy Srinivasan for serving on my dissertation committee. I would also like to acknowledge the support of Goodrich Engine Control Systems, Air Force Research Laboratory (AFRL) and National Aeronautics and Space Administration (NASA) through Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) programs. I would like to thank Mr. Paul Paluszewski for his help, advice and more importantly, for his trust and believing in me with the research responsibilities. I would also like to thank Dr. Alireza Behbahani for his help and encouragement during my graduate studies. I would also like to thank Mr. Stephen Reeps, Ms. Deb Trailor, Mr. Bill Storey, and Mr. Jonathan DeCastro for their support and technical guidance. I would like to express my gratitude to Prof. Rajkumar S. Pant for his encouragement to pursue a Ph.D. in dynamics and control systems. I would also like to thank my colleagues, Dr. Praveen Shankar, Dr. Wenfei Li, Dr. Hsun-Hsuan Huang, Dr. Nagini Devarakonda, Mr. Deepak Saluru and Mr. Jonathan v Kratz for their discussions and for creating a positive research environment. I would like to offer my special thanks to my parents, Mr. Kishore and Mrs. Ashwini and my sister, Ruchita, for their love, support and tremendous encouragement over the years. Most of all, I deeply appreciate the love and support of my wife, Uttara, who has been a constant source of encouragement. Special thanks to my friends; Adwait, Anup, Kanika, Ninad, Parth, Pinak, Rahul, Renuka, Shubhanan, Suraj and Tejas for supporting me get through this process. vi VITA 2006................................................................B.E., Mechanical Engineering, University of Pune, India 2008................................................................M.S., Aeronautical & Astronautical Engineering, The Ohio State University PUBLICATIONS R.K. Yedavalli and R.K. Belapurkar, “Application of Wireless Sensor Networks to Aircraft Control and Health Management Systems”, Journal of Control Theory and Applications”, Vol. 9, No.1, pp. 28-33, February 2011 R.K. Yedavalli, R.K. Belapurkar and A. Behbahani, “Design of Distributed Engine Control Systems for Stability Under Communication Packet Dropouts”, AIAA Journal of Guidance, Control and Dynamics, Vol. 32, No. 5, pp.1544-1549, Sept.- Oct. 2009 FIELDS OF STUDY Major Field: Aeronautical and Astronautical Engineering vii TABLE OF CONTENTS Abstract .............................................................................................................................. ii Acknowledgments ............................................................................................................. v Vita ................................................................................................................................... vii List of Tables ................................................................................................................... xii List of Figures ................................................................................................................. xiii 1. Introduction ............................................................................................................... 1 1.1. Current Gas Turbine Engine Control System ..................................................... 2 1.2. Distributed Engine Control Systems ................................................................... 7 1.3. Problem Statement ............................................................................................ 10 1.4. Dissertation Contribution .................................................................................. 12 1.5. Dissertation Organization ................................................................................. 14 2. Turbine engine control systems ............................................................................. 16 2.1. Control System Architecture............................................................................. 17 2.2. Thermal Management ....................................................................................... 21 viii 2.3. Cockpit Engine Indications ............................................................................... 22 2.4. Control System Design ..................................................................................... 23 2.4.1. Variable bleed valve control ......................................................................... 24 2.4.2. Variable stator vane control ......................................................................... 24 2.4.3. Fuel Control System ...................................................................................... 25 2.4.4. Set-point Control Design .............................................................................. 26 2.4.5. Transient Control Design ............................................................................. 27 2.4.6. Limit Controllers ........................................................................................... 28 2.5. Advanced Control Methods .............................................................................. 30 2.5.1. Engine Degradation and Health Management ............................................. 30 2.5.2. Multivariable Control ................................................................................... 30 2.5.3. Active Control ............................................................................................... 31 2.5.4.
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