MAIN RESEARCH AREAS:
UAV Design, Instrumentation, and Flight Testing
FCSL has more than 15 years of experience in designing, manufacturing, and flight-testing customized unmanned research aircraft platforms. FCSL also operates a dedicated flight-testing facility with a 3,300 ft paved runway. To date, close to 450 experimental flights have been conducted at FCSL for different research purposes.
Over a dozen airframes have been developed at FCSL by undergraduate and graduate students, including two aircraft families: YF-22 and Phastball.
The WVU YF-22 research platforms, with a total of four aircraft, have been utilized for various research projects, including the aircraft parameter identification, formation flight control, fault-tolerant flight control, and sensor fusion. Each aircraft is approximately 2.4 m long with a 2 m wing span, and weighs approximately 22.5 Kg. The aircraft is powered with a miniature turbine that produces 125 N of static thrust.
The newly developed Phastball platform, with a total of five aircraft, is designed to simplify the flight testing operations and to reduce the operational cost. The Phastball airframe has a wingspan of approximately 2.4 m and weights 10.5 kg, including a 3 Kg payload capacity. The aircraft features two brushless electric ducted fans powered by lithium-polymer battery packs. Of the five airframes built so far, the ‘Red Phastball’ is a dedicated data acquisition platform for sensor fusion research, the ‘Blue Phastball’ is used for validating fault-tolerant flight control laws, the ‘Green Phastball’ is used for aircraft propulsion system analysis and failure accommodation, the ‘Phastball-Zero’ is an airborne imaging and remote sensing platform, and ‘SharpShooter’ is an air sample collection platform.
The on-board avionics have undergone numerous iterations of development over the course of the last 15 years and the most recent generation, the ‘Gen-V’ avionics incorporates many design features specifically introduced for the purposes of fault-tolerant flight control research. The main objective of this design is to emulate different failure conditions in flight, to allow reconfiguration of available control resources, and to provide a flexible interface for integrating both human and machine decision-making capabilities. Due to the high risk and uncertain nature of a flight testing program that explores different failure conditions, the avionics itself is designed with several safety features to ensure a reliable operation and mode switching, and to reduce the risk of a Single Point of Failure (SPOF).
The avionics system is composed of a PC-104 based main flight computer, a sensor suite, an R/C sub-system, a communication sub-system, a power sub-system, and a set of real-time flight software for health monitoring, signal conditioning & distribution, Guidance, Navigation, and Control (GNC), and failsafe functions. One of the salient features of the ‘Gen-V’ fault-tolerant avionics design is its capability to provide a reliable and flexible interface between control commands generated by humans and the on-board automatic controller. Specifically, it enables the following operational modes with nine independently controlled channels:
- Manual Mode, where the human pilot has full authority on all control channels;
- Partial Autonomous Mode, where a subset of the control channels is under pilot control; the rest of the control channels are under automatic control;
- Failure Emulation Mode, where a specific failure condition can be injected by the on-board computer, while the remaining channels could be under either pilot control or automatic control. The types of failure scenarios include actuator failure, sensor failure, and engine failure;
- Pilot-In-The-Loop Mode, where the automatic control system augments the pilot command. This mode also enable the possibility to study human responses under a sub-system failure condition;
- Fully Autonomous Mode, where the pilot serves as an observer and safety backup.
Gross, J., Gu, Y., Seanor, B., Gururajan, S., and Napolitano, M.R., “Advanced Research Integrated Avionics (ARIA) System for Fault-Tolerant Flight Research,” 2009 AIAA Guidance, Navigation, and Control Conference, AIAA-2009-5659, Chicago, Illinois, Aug. 10-13, 2009.
Gu, Y., Seanor, B., Gururajan, S., and Napolitano, M.R., “Integrated Avionics System for Research UAVs,” 2008 AIAA Guidance, Navigation, and Control Conference, AIAA 2008-7490, Honolulu, Hawaii, August 2008.
Gu, Y., Seanor, B., Campa, G., Napolitano, M. R., Rowe, L., and Gururajan, S., “Autonomous Formation Flight: Hardware Development,” 14th Mediterranean Conference on Control and Automation, pp.1-6, Ancona, Italy, June 2006.