(Advisor: Prof. Dimitri Mavris)
will propose a doctoral thesis entitled,
"A Methodology for the Development of Integrated Flight-Propulsion Control Laws for Distributed Electric Propulsion Aircraft"
Friday, March 27 at 2 p.m.
Loss of control events have become the foremost cause of commercial jet accidents with fatalities worldwide in recent years, resulting in over half of the fatalities between 2008 and 2017. Further, 31% of loss of control accidents involving commercial jets were due to system/component failure/malfunctions and 23% were due to damage to the aircraft, according to a study done by NASA’s Integrated Resilient Aircraft Control project. Historically, throttles-only control has demonstrated itself as an effective means of maintaining attitude control during these events by using collective and differential thrust to control the pitch and roll of the aircraft (e.g., Delta Airlines Flight 1080, United Airlines Flight 232, and the 2003 DHL attempted shootdown incident). In response to the National Transportation Safety Board’s recommendation of “research and development into backup flight control systems that employ an alternative source of motive power” within the United Airlines Flight 232 accident report, NASA’s Propulsion Controlled Aircraft project demonstrated the viability of augmented thrust-only control systems on various aircraft through a series of flight tests and simulations.
Some of the limitations of integrated flight-propulsion control on aircraft with conventional gas turbine propulsion, including the control of roll attitude through sideslip, may be overcome by distributed electric propulsion. The numerous electric motors allow for different combinations of individual propulsor power lever angles to satisfy a desired amount of overall thrust, while also inducing moments required to control the attitude of an aircraft. In addition, distributed electric propulsion aircraft may open up new opportunities in integrated flight-propulsion control by capitalizing on the fast response of electric motors, the placement of propulsors to improve aircraft handling characteristics, and the ability to reallocate power among the operative propulsors to resolve asymmetric thrust conditions. The use of a distributed electric propulsion system for aircraft attitude control has been demonstrated on two small unmanned aerial vehicles (UAVs); however, several commercial aircraft concepts use a turbo-generator to satisfy mission performance requirements, which complicates propulsion system dynamics and integrated flight-propulsion control compared to a purely electric aircraft.
This thesis will establish a methodology for the development of an integrated flight-propulsion control system for distributed electric propulsion aircraft starting from concept formulation. To resolve the over-actuation problem posed by the electric propulsors, model predictive control will be used for aircraft attitude control. The reactive properties of the electrical components will be modeled to characterize the apparent power flow within the propulsion system during operation. After exploring the implementation of an integrated flight-propulsion control system on a turbo-electric distributed propulsion aircraft, the handling qualities of the aircraft will be evaluated during nominal and off-nominal operation.
- · Prof. Dimitri Mavris – School of Aerospace Engineering (advisor)
- · Prof. Daniel Schrage – School of Aerospace Engineering
- · Dr. Johnathan Gladin - School of Aerospace Engineering