• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.534-536
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• 1998

The helicopter system is non-linear and complex. Futhermore, because of absence of accurate mathematical model, it is difficult accurately to control its attitude. therefore, we propose a PID Neural Networks control technique to control efficiently its elevation angle and azimuth one. The coefficients of PID controller are automatically adjusted by the back-propagation algorithm of a neural network. The simulation results using MATLAB are introduced.

• Korean Management Science Review
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• v.24 no.2
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• pp.81-93
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• 2007

Achieving a target operational availability is more economical and efficient than having many quantities of the weapon system, since the cost of weapon system becomes expensive. The intent of this study is twofold; first, we develop the simulation model to determine the optimal inventory level of the maintenance float while achieving a target operational availability of the Korean-made helicopter. The quantity decision model considers following factors such as a reliability. a turn around time(TAT). a protection level for inventory, and so on. Second, we analyze whether the existence of a lateral transshipment among bases and the reduction of TAT relate to an inventory level and the operational availability. The research result shows that both TAT and lateral transshipment have an effect on reducing the inventory level of the maintenance float and improving an operational availability.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2470-2472
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• 2001

This paper describes the application of a fuzzy-tuning PID controller to a 3-DOF attitude control of a small model helicopter in hover for the compensation of coupling effects between each axis and system uncertainties due to the variation of engine RPM. A Low-level PID controller is designed by Ziegler-Nichols method and its gains are tuned by a high-level fuzzy system based on error states and its time derivatives. The experimental results show that the attitude control performance of fuzzy-tuning PID controller is improved comparing with that of a Ziegler-Nichols PID controller and fuzzy controller.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2453-2455
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• 2005

We represent an efficient intelligent digital redesign method for a Takagi-Sugeno (T-S) fuzzy system Intelligent digital redesign means that an existing analog fuzzy-model-based controller converts to equivalent digital counter part in the sense of state-matching. The proposed method performs previous work, moreover, it allows re matching the states of the overall closed-loop T-S fuzzy system with the predesigned analog fuzzy-model-based controller. And the problem of stability represent convex optimization problem and cast into linear matrix inequality (LMI) framework. This method applies to the helicopter systems which are the nonlinear plant and determine the feasibility and effectiveness of the proposed method.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1811-1813
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• 2005

We represent an efficient intelligent digital redesign method for a Takagi-Sugeno(T-S) fuzzy system. Intelligent digital redesign means that an existing analog fuzzy-model-based controller converts to equivalent digital counter part in the sense of state-matching. The proposed method performs previous work, moreover, it allows to matching the states of the overall closed-loop T-S fuzzy system with the predesigned analog fuzzy-model-based controller. And the problem of stability represent convex optimization problem and cast into linear matrix inequality(LMI) framework. This method applies to the helicopter systems which are the nonlinear plant and determine the feasibility and effectiveness of the proposed method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.159-164
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• 2016

This paper reports the load factor logic design for a fly-by-wire helicopter flight envelope protection. As a helicopter is very complex system with a rotor, fuselage, engine, etc., there are many constraints on the flight region. Because of these constraints, pilots should consider them carefully and have a heavy workload, which causes controllability degradation. In this respect, automatic logic is needed to free the pilot from these considerations. As one of these logics, the flight envelope protection logic for the load factor of a FBW helicopter was designed. The flight to exceed the load factor is caused by an abrupt pitch cyclic stick change. In this scheme, the load factor limit logic was added between the pilot stick command block and pitch attitude command block. From the current load value, the available attitude range was calculated dynamically and simulated on the helicopter simulator model to verify the performance. A comparison of the simulation results at the hovering and forward speed region with and without applying the load limiting logic showed that the load factor limit was exceeded more than 20% when the logic was not applied, whereas with the load factor limit logic the load factor was within the limit. In conclusion, a dynamically allocated limitation logic to helicopter FBW controller was verified by simulation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.7
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• pp.524-531
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• 2013

This work aims at developing a RTB (Rotor Track and Balance) system to alleviate imbalances originating from various sources encountered during blade manufacturing process and environmental factors. The analytical RTB model is determined based on the linear regression analysis to relate the RTB adjustment parameters and their track and vibration results. The model is validated using the flight test data of a full helicopter. It is demonstrated that the linearized model has been correlated well with the test data. A hybrid optimization problem is formulated to find the best solution of the RTB adjustment parameters using the genetic algorithm combined with the PSO (Particle Swarm Optimization) algorithm. The optimization results reveal that both track deviations and vibration levels under various flight conditions become decreased within the allowable tolerances.

• The KIPS Transactions:PartA
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• v.14A no.5
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• pp.255-262
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• 2007

Physically-based researches on simulating helicopter motions have been achieved in the field of aeronautics, aerodynamics and others. These results, however, have not been appled in the computer graphics area, mainly due to their complex equations and heavy computations. In this paper, we propose a dynamics model of helicopter rotor blades, which would be easy to implement, and suitable for real-time simulations of helicopters in the computer graphics area. Helicopters fly by the forces due to the collisions between air and rotor blades. These forces can be interpreted as the impulsive forces between the fluid and the rigid body. Based on these impulsive forces, we propose an approximated dynamics model of rotor blades, and it enables us to simulate the helicopter motions using existing rigid body simulation methods. We compute forces due to the movement of rotor blades according to the Newton's method, to achieve its real-time computations. Our prototype implementation shows real-time aerial navigation of helicopters, which are murk similar to the realistic motions.

• Structural Engineering and Mechanics
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• v.27 no.2
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• pp.243-257
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• 2007

A numerically efficient superelement is proposed as a low degree of freedom model for dynamic analysis of rotating tapered beams. The element uses a combination of polynomials and trigonometric functions as shape functions in what is also called the Fourier-p approach. Only a single element is needed to obtain good modal frequency prediction with the analysis and assembly time being considerably less than for conventional elements. The superelement also allows an easy incorporation of polynomial variations of mass and stiffness properties typically used to model helicopter and wind turbine blades. Comparable results are obtained using one superelement with only 14 degrees of freedom compared to 50 conventional finite elements with cubic shape functions with a total of 100 degrees of freedom for a rotating cantilever beam. Excellent agreement is also shown with results from the published literature for uniform and tapered beams with cantilever and hinged boundary conditions. The element developed in this work can be used to model rotating beam substructures as a part of complete finite element model of helicopters and wind turbines.

• The Journal of the Korea Contents Association
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• v.19 no.7
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• pp.436-443
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• 2019

The purpose of this paper is to establish a predictive model by analyzing the influence and correlation of factors affecting the fuel consumption of unmanned helicopters in Captive Flight Test. In this study, a four-factor two-level full factorial experiment was designed and tested using the design of experiments, results were analyzed to derive the main effects and interactions of the factors, and the predictive model was established through regression analysis. It is expected that the results from this study contribute to carrying out Captive Flight Test efficiently and the improvement of the test capability of Electronic Testing Range.