• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.1
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• pp.9-16
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• 2009

The analysis of an aircraft flight dynamics is recently very convenient because of the introduction of state-space method and a well-developed package software. The representation of a dynamic system is described as a simple form of matrix calculation and the unique form of model is available for the linear or nonlinear, time variant or time invariant, mono variable or multi variable system with state-space method. And this analysis can be simplified with the specific functions of a package software and it is very simplified to execute the simulation of the dynamic characteristics for an aircraft model with an interactive graphical treatment. The purpose of this study is to develope an educational flight simulator for the students who need to analyze the dynamic characteristics of an aircraft that is primarily to execute the simulation for the analysis of the transient response and frequency response of an aircraft stability. Furthermore the dynamic characteristics of an aircraft motion is set up as dynamical animation tool for the control response on 3-axis motions of an aircraft.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.1
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• pp.162-168
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• 2008

A design objective for variable stability flight control system is to develop a controller of in-flight simulation capability that forces the aircraft being flown to follow the dynamics of other aircraft. This paper presents a model-following variable stability control system (VSS) for in-flight simulation which consists of feedforward and feedback control laws, the aircraft dynamic model to be simulated, and switching and fader logics to reduce the transient effect between two aircraft dynamics. The separate design techniques for feedforward and feedback control law proposals are based on model matching and augmented linear quadratic (LQ) techniques. The system allows pilots to select and engage VSS mode, and when deselected, the aircraft reverts to the baseline flight control system. Both the baseline flight control laws and VSS control laws are computed continuously during flight. Initialization of the state values are necessary to prevent instability, since VSS control laws have integrators and filters in longitudinal, and lateral/directional axes. This paper demonstrates and validates the effectiveness and quality of VSS with F-16 models embedded in T-50 in-flight simulation aircraft.

• Journal of Biosystems Engineering
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• v.36 no.6
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• pp.467-475
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• 2011

Aerial spraying technology using a small unmanned helicopter is an efficient and practical tool to achieve stable agricultural production to improve the working condition. An attitude controller for the agricultural helicopter would be helpful to aerial application operator. In order to construct the flight controller, a state space model of the helicopter should be identified using a dynamic analysis program, such as CIFER$^{(R)}$. To obtain the state space a model of the helicopter, frequency-sweep flight tests were performed and time history data were acquired using a custom-built stick position transmitter. Four elements of stick commands were accessed for the collective pitch (heave), aileron (roll), elevator (pitch), rudder (yaw) maneuvers. The test results showed that rudder stick position signal was highly linear with rudder input channel signal of the receiver; however, collective pitch stick position signal was exponentially manipulated for the convenience of control stick handling. The acquired stick position and flight dynamic data during sweep tests would be analyzed in the followed study.

• Journal of Advanced Navigation Technology
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• v.20 no.5
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• pp.387-393
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• 2016

To perform realistic air traffic control (ATC) simulation in various air traffic situations, an aircraft dynamic model that is accurate and efficient is required. In this research, an improved five degree of freedom (5-DOF) dynamic model with feedback control and guidance law is developed, which utilizes selected performance data and operational specifications from the base of aircraft data (BADA) and estimations using aircraft design techniques to improve the simulation fidelity. In addition, takeoff weight is estimated based on the aircraft type and flight plan to improve simulation accuracy. The dynamic model is validated by comparing the simulation results with recorded flight trajectories. An ATC simulation system using this 5-DOF model can be used for various ATC related research.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.1
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• pp.38-44
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• 1998

The modified maximum likelihood estimation method is used to estimate the nondimensional aerodynamic derivatives of a single turbo-prop aircraft at a specified flight condition for the best deduction of the dynamic characteristics. In wind axes the six degree of freedom equations are algebraically linearized so that the linear state equation contains aerodynamic derivatives in a state-space form and is used in the maximum likelihood method. The simulated data added with the measurement noise is used as a flight test data which is necessary to the estimation of nondimensional aerodynamic derivatives. It is obtained by implementing the 6-DOF nonlinear flight simulation. In the flight simulation, the effects of several control input types, control deflection amplitudes, and the turbulence intensities on the statistical convergence criteria are also examined and quantitative analysis of the results is discussed.

• Advances in nano research
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• v.15 no.6
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• pp.579-585
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• 2023

This research delves into the intricate dynamics of the flight response exhibited by a golf ball that incorporates nanoparticles with the goal of enhancing its overall quality. The golf ball is meticulously modeled utilizing beam elements, and the impact of nanoparticles is intricately captured through the application of the Halpin-Tsai theory. Employing a numerical solution, the study thoroughly explores the flight response of the golf ball, taking into account the nuanced effects of the embedded nanoparticles. By scrutinizing the aerodynamic characteristics through advanced simulations, this investigation aims to provide valuable insights that could potentially revolutionize the design and performance of golf equipment, offering a pathway towards superior quality and enhanced functionality in the realm of golf ball technology. Results show that increase in the volume percent of nanoparticles, improves the flight response of the golf ball.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1848-1849
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• 2006

The new robust controller design method is proposed for the flight control systems with model uncertainties. The proposed control system is a combination of the adaptive dynamic surface control (DSC) technique and the self recurrent wavelet neural network (SRWNN). The adaptive DSC technique provides us with the ability to overcome the "explosion of complexity" problem of the backstepping controller. The SRWNNs are used to observe the arbitrary model uncertainties of flight systems and all their weights are trained on-line. From the Lyapunov stability analysis, their adaptation laws are induced and the uniformly ultimately boundedness of all signals in a closed-loop adaptive system is proved. Finally, simulation results for a high performance aircraft (F-16) are utilized to validate the good tracking performance and robustness of the proposed control system.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.12
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• pp.1212-1217
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• 2008

This paper studies the feasibility of using the nonlinear model predictive control as a formation flight control algorithm for unmanned aerial vehicles. The optimal control inputs for formation flight are calculated through the cost function which incorporates the relative positions of the individual vehicles to maintain a desired formation and also the inequality constraints on inputs and states using the Karush-Kuhn-Tucker conditions. In the nonlinear model predictive control setting, the optimal control inputs are implemented in a receding horizon manner, which is suitable for dealing with dynamic constraints. Numerical simulations are executed for the validation of the proposed scheme.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.12
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• pp.857-866
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• 2022

Fixed-wing UAVs have long endurance and range capabilities compared to other aerial platforms. These advantages led fixed-wing UAVs to become a popular platform for reconnaissance missions in the military. In this research, we modeled fixed-wing UAVs, including the landing gear model and developed a guidance and control system for flight control computers to construct a HILS environment. We also developed an autopilot system that includes automated take-off, cruise, and landing control for UAVs. We also retrived the Aerodynamic coefficients an UAV using Datcom and AVL software and used them for 6 degrees of freedom modeling. The Flight control computer calculates guidance commands using the Carrot chasing guidance law after distinguishing the condition of the UAV based on 16 pre-defined flight modes and calculates control inputs using Nonlinear Dynamic Inversion (NDI) control scheme. We used RTNngine to integrate the Simulink model and flight control computer for HILS environment formulation.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.2
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• pp.53-60
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• 2007

This paper presents a robust nonlinear autopilot design method based on dynamic inversion and PI(Proportional-Integral) control law. The new controller structure which is different from previous work is composed of classical linear PI control law and nonlinear fast dynamic inversion. A pitch axis model of highly maneuverable missiles and a linearized model for designing Pl controller are presented. The performance of proposed method is illustrated via nonlinear simulations including aerodynamic uncertainties and actuator dynamics.