• 대한산업공학회지
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• 제39권5호
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• pp.374-382
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• 2013

Robust design method developed by Genichi Taguchi has been very popular since the 1980s and there have been many academic and applied research works on this topic. However, college students and engineers in companies have had difficulty in understanding the method. This paper presents a procedure to implement the robust design method by an easy-to-execute paper helicopter experiment. A crossed array was adopted, which consists of a resolution IV fractional factorial design with 6 control factors and a factorial design with 3 noise factors. Three performance measures were analyzed; signal-to-noise ratio, mean, and standard deviation of the falling time of the paper helicopter that is to be maximized. Control-noise interaction plots are also given to evaluate the degree of the sensitivity of each level of the control factors to the noise factors. The procedure presented in this paper can be helpful to those who want to have basic knowledge in the robust design method.

• 한국군사과학기술학회지
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• 제13권6호
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• pp.1099-1105
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• 2010

The purpose of this paper is to propose a methodology that can estimate optimal requirement of attack helicopter Korea army will be operating in future. For estimating optimal requirement, attack helicopter's operation concept, performance, battlefield environment and enemy threat are considered. We use a wargame model, AAsim(Army Aviation simulation), as a analytic simulation model which is used to analyze DOTMLPF and operation in army aviation field. In this paper, we conduct battle experiment for anti armored corps operation which reflects attack helicopter's combat effectiveness very well. As a result of simulation, the destructive rate for enemy armored corps per each attack helicopter can be calculated. In this paper, we propose optimal requirement of attack helicopter using that destructive rate for enemy armored corps.

• 품질경영학회지
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• 제43권4호
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• pp.589-606
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• 2015

Purpose: In developing new products, reducing performance variation is important for competitiveness factors such as quality, cost, and delivery. This paper aims at evaluating three performance variations; measurement, performance evaluation, and manufacturing variations, and then improving product and process design, focused on paper helicopter making case study. Methods: For measurement system analysis, gage R&R (repeatability and reproducibility), linearity, stability are evaluated. Since gage R&R are not satisfactory, the measurement system is improved by adopting voice memos application of iPhone and providing standard measurement procedure. To evaluate performance variation, product deterioration and environment factor (wind speed) is considered. Since the existing design is sensitive to these noise factors, a new product design is developed, which is proven to be robust to the noise factors. Finally, manufacturing variations are evaluated with five factors which can cause variation in flight time. To reduce the impact of three significant factors, three improvement methods are applied. Results: Three performance variations are evaluated and robust paper helicopter design is presented. Conclusion: To reduce measurement and process variations, improved measurement method and paper helicopter making procedure are proposed. A new product design is also presented which is robust to deterioration and environmental variation. This paper is expected to benefit students and practitioners who want to have hands-on knowledge on new product quality improvement.

• 제어로봇시스템학회논문지
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• 제21권7호
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• pp.677-683
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• 2015

This paper proposes a helicopter direction adjustment system using barycenter shift. Most conventional methods for direction adjustment of uniaxial helicopters rely on the angle of inclination of the main rotor. However, the inherent burden of the bearing of the main rotor and serious abrasion of the helicopter using the above methods may results in loss of balance. To decrease abrasion and enhance the barycenter stability, the proposed method was used to shift the barycenter of the helicopter instead of the main rotor for direction adjustment. We set a biaxial ARM on a uniaxial helicopter to adjust the direction of ARM pointing as well as to realize stable direction control when the helicopter loses its balance. The method may enhance the landing safety of helicopters in emergencies. Uniaxial helicopters can be controlled under any environment by adjusting the motor parameters of the ARM which is dependent on the center of mass using neural network. The experiment results show that the helicopter can return to the starting position quickly under the external disturbance.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.92-92
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• 2000

Helicopter offer the signigicant advantage over traditional air vehicles, in that the provide extended maneuverability, such as vertical climb, hovering, longitudinal and lateral flight, hovering turns and bank turns. But helicopter have the strong cross couplings and nonlinearities for each lateral, longitudinal and rotational motion mutually. However, it is possible to ignore this couplings for the hovering condition, so using this properties we can control the attitude of helicopter. That is, by implementing the dynamic of each rotational axis(roll, pitch, yaw) of independent mutually, 3-DOF(degree of Freedom) attitude control for the helicopter is possible. In this paper, we identify decoupled input-coutput relations of each three rotational axis about the helicopter mounted on the 3-DOF gimbal by experiment, and on these basis implement 3-DOF attitude controller using the PID control method.

• International Journal of Aeronautical and Space Sciences
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• 제9권2호
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• pp.48-57
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• 2008

The noise is one of the serious problems concerning helicopters operations. The issue of helicopter external noise generated mainly from a helicopter rotor has always affected the use of rotorcrafts, especially in the urban environment. The noise sources depend on the flight configurations. In particular, a noise generated by the interaction between blades and tip vortices mainly occurs during descent flight. This noise is called blade-vortex interaction (BVI) noise, and this BVI noise is particularly penalizing for helicopters. In this paper, a numerical study to capture the BVI noise is carried out. The numerical study is performed in two phases. In the first phase, a 2D simulation based on parallel BYI event of Kitapliglu et al experiment is performed. In the second phase, 3D simulation based on HART Ⅱ experiment is performed. Several experimental data such as thrust, torque, blade sectional load, its derivative and vortex location are compared with calculation results and the comparison showed reasonably good agreement.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2001년도 추계학술대회 학술발표 논문집
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• pp.141-144
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• 2001

This paper proposes a decentralized control technique for 2-dimensional experimental helicopter systems. The decentralized control technique is especially suitable in large-scale control systems. We derive the stabilization condition for the interconnected Takagi-Sugeno (75) fuzzy system using the rigorous tool - Lyapunov stability criterion and formulate the controller design condition in terms of linear matrix inequality (LMI). To demonstrate the feasibility of the proposed method, we include the experiment result as well as a computer simulation one, which strongly convinces us the applicability to the industry.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2171-2175
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• 2002

Helicopter dynamics are plenty of nonlinearity. A complete mathematical model including propeller dynamics and fortes generated by the propellers is very difficult to obtain. So the method used to design to design a controller is a parameter estimation. Design controller based on variable structure system. This paper deals with LQR control technique to control efficiently, its elevation angle and azimuth one. The purpose of the experiment is to design a controller allows to use a desired elevation angle and azimuth ones. The system model has a helicopter model with 2-degree-of freedom. The simulation results were verified usefulness of controller.

• 대한기계학회논문집
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• 제15권2호
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• pp.497-506
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• 1991

In this paper, a new construction for training simulator of R/C helicopter based on two types of servo controller is proposed. Two modified algorithms (algorithm I and II) for servo controller design are presented. Algorithm I is developed by adopting Davison's method in the case that the expressions for the homogeneous differential equations of reference input and disturbance are different types, and algorithm II is done by considering error weighting function for the servo controller of algorithm I . The linear fractional transformation method is incorporated in both design methods in order to assign the closed loop poles of the servo system in a specified region. The helicopter simulator is composed by the gimbals with two freedom of rolling and pitching. The reliability and validity for the design methods of the proposed servo controller are investigated through the practical experiment for the simulator by using 16bits micro-computer with A/D and D/A converters. It can be observered from the experimental results that the proposed servo controller is applicable to practical plants since the simulator is robust for the arbitrary disturbance and it follows to the given reference input without significant steady state error.

• 한국지능시스템학회논문지
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• 제25권4호
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• pp.398-404
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• 2015

본 논문에서는 관성측정장치를 기반으로 블루투스 환경에서의 자율비행을 위한 멀티 로터형 헬리콥터에 대한 설계 및 성능을 제시하였다. 멀티 로터관련 다양한 연구가 진행되어오고 있긴 하지만 최근에는 다양한 서비스를 목적으로 짐벌이 장착된 헥사로터형의 헬리콥터에 대한 관심이 모아지고 있다. 따라서, 본 논문에서는 지상의 원격조정 PC나 고성능의 원격제어장치나 영상시스템과 같은 외부보조 시스템 없이 연구와 구조활동, 모니터링 활동을 수행할 수 있는 컴팩트하고 자율비행을 위한 헥사로터(hexa rotor)형 헬리콥터에 대한 하드웨어 및 소프트웨어를 소개하고자 한다. 제안한 시스템은 헥사로터 헬리콥터의 구조와 관성측정장치 관련 하드웨어 구성과 수학적 모델링 및 시뮬레이션 결과를 각각 제시하였다. 또한, IMU 구현을 위하여 MCU(ARM-cortex) 보드를 장착하여 각 로터의 회전과 관성 측정장치의 입력신호에 대한 상태를 제어할 수 있도록 하였다. 그리고 시스템 시뮬레이션과 실험을 통한 시스템의 성능을 각각 검증하였다.