Jong-Min Ahn

Flight test of a Flying-Wing Type UAV with Partial Wing Loss Using Neural Network Controller

This paper presents flight test result of flying-wing type UAV with partial wing loss using neural network controller. 22% and 33% loss of wing area moment were considered for the damage configuration. A new trim state was obtained for each damaged model with the variation of mass, center of gravity and moment of inertia. A numerical simulation was performed to investigate the changed flight dynamics. It is verified that the damaged UAV shows sluggish roll behavior with unstable longitudinal response. A neural network based adaptive controller combined with feedback linearization was designed in order to compensate for the partial damage. It is verified that the instability caused by partial wing damage can be effectively controlled, and the overall system can be stabilized via neural network controller.

Analysis of partial wing damage on flying-wing unmanned air vehicle

This article investigates the effect of asymmetric wing damage on flight dynamic characteristics of a flying-wing single motor unmanned air vehicle. To construct a six degree-of-freedom model of the damaged aircraft, a flying-wing type unmanned aerial vehicle is designed, and the wind tunnel test for damaged configurations is performed to identify the change of aerodynamic coefficients. The changes of mass, center of gravity, and moment of inertia are also calculated for each damage configuration with CATIA. The changed trim states are calculated depending on the severity of damage, and the movements of poles in longitudinal/lateral-directional flight modes are examined to evaluate the change of the dynamic stability and performance. Numerical simulations and eigenvalue analyses are performed to investigate the altered flight dynamics. It is verified that an asymmetrically wing-damaged unmanned air vehicle shows a sluggish roll behavior with longitudinal instability, and the result of this study can be a cornerstone for the future research on reconfigurable flight controller design against aircraft damage.

Research flight control computer development for the flight control switching mechanism

The flight control switching mechanism system (FCSWMS) can give a pilot-selectable research control law capability due to the research flight control computer (RFCC) and the basis triplex primary flight control computer (PFCC), therefore this system provides a flexible platform for control law algorithm research. The research flight control system (RFCS) supports a design capability for relatively fast control law modifications and development, while retaining safety of flight through the PFCC. The RFCS processor was designed by more improved performance than primary FCC processor for the implementation of switching algorithm on the FCSWMS. The application software based on VxWorks operating system was developed on the tornado development environment. The verification and validation of research flight control computer system and software was performed in the hardware-in-the loop simulation environment including the primary flight control computer, cockpit and etc.. The RFCS verified through the software and system test will be useful for a variety of advanced control law research and future flight control system development.

Flight test of flying-wing type unmanned aerial vehicle with partial wing-loss

This paper investigates experimental evaluation via flight tests for applying adaptive neural network controller to a flying-wing type unmanned aerial vehicle experiencing partial wing-loss. For this, six-degree-of-freedom numerical model is constructed taking into account damage-induced changes to the unmanned aerial vehicle in aerodynamic coefficients, mass, center of gravity, and moments of inertia. Numerical simulations are performed to investigate the flight dynamics change and to verify the performance of the neural network based controller. During the flight test, main wing-loss is artificially generated by 22% or 33% area moment. The flight test verifies that the damaged unmanned aerial vehicle shows drastic roll behavior with the unstable longitudinal response, and the neural network based adaptive controller combined with feedback linearization successfully compensates for the wing damage.

Study on Korean In-Flight Simulator Aircraft

This paper presented here contains development of variable stability system(VSS) control laws for the KIFS (Korean In-Flight Simulator) aircraft to simulate the dynamics of F-16 aircraft. Development of VSS Control law for pitch rate, roll rate, yaw rate simulation for three specified flight conditions using Model Following Technique with rate feedback autopilot for stability provision. The direct lift force controller was also added to the developed VSS control law to simulate the pitch rate and normal g-load simultaneously. The simulation results show high accuracy of F-16 aircraft`s pitch, roll, yaw rate and g-load simulation.

Development of Switching System for Flight Control Law

This paper deals with a development of flight control law switching system which can be used for flight test of the research control law by switching control law during flight. Through this research program, fader logic and integrator stabilization design has been introduced to minimize the transient response of aircraft caused by flight control law switching and to prevent the divergence of the integrator included in the control law in standby mode. MIL-STD-1553B communication was applied to transfer the data between the two control laws. This paper introduce the control law switching system architecture and major design concept and include the system verification and validation result performed on the flying quality simulator of the advanced trainer