• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.590-593
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• 2005

Unmanned Helicopter has several abilities such as vertical Take off, hovering, low speed flight at low altitude. Such vehicles are becoming popular in actual applications such as search and rescue, aerial reconnaissance and surveillance. These vehicles also used under risky environments without threatening the life of a pilot. Since a small unmanned helicopter is very sensitive to environmental conditions, it is generally known that the flight control is very difficult problems. The nonlinear adaptive fuzzy controller design procedure and its applications for altitude control of unmanned helicopter were described in the paper. This research was concentrated on describing the design methodologies of altitude controller design for small unmanned helicopter acquiring autonomous take off and vertical movement. The design methodologies and performance of the altitude controller were simulated and verified with an adaptive fuzzy controller. Throughout simulation results, I showed that the proposed adaptive controllers have enhanced control performance such as robustness, effectiveness and safety, in the altitude control of the unmanned helicopter.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1127-1128
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• 2008

In this paper, we propose a control method to improve control performance for a Quad-rotor Unmanned Aerial Vehicle's stabilization. The proposed method is the Fuzzy+I control that contains a fuzzy controller which processes signals from the error and the change of error, and generates the control signal by summing up fuzzy output signal and integral signal. We simulated and experimented on the fuzzy+I control method by implementing Quad-rotor UAV that is able to hovering, for the purpose of verifying the effectiveness of the proposed fuzzy+I control method in comparison with general PID control, and we found out that fuzzy+I controller improved control performance of the system.

• International Journal of Aeronautical and Space Sciences
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• v.5 no.2
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• pp.62-70
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• 2004

CFD method has been coupled with a time-marching free-wake model by usingfield velocity approach suggested by J. D. Baeder (Ref. 1). The coupled method hasbeen applied to rectangular and BERP-like blades and the calculated perfonnance dataare compared with the experimental results.For hovering analysis, the present method could yield sufficiently good resultswith reasonable computation time and is particularly suitable for the flow fieldanalysis with the complex shaped blade.

• Journal of Advanced Navigation Technology
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• v.21 no.5
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• pp.450-458
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• 2017

This paper presents dynamic modelling and simulation study on attitude/altitude control of an insect-mimicking flapping micro aerial vehicle during hovering. Mathematical modelling consists of three parts: simplified flapping kinematics, flapping-wing aerodynamics, and six degree of freedom dynamics. Attitude stabilization is accomplished through linear quadratic regulator based on the linearized model of the time-varying nonlinear system, and altitude control is designed in the outer loop using PID control. The performance of the proposed controller is verified through numerical simulation where attitude stabilization and altitude control is done for hovering. In addition, it is confirmed that the attitude channel by periodic control is marginally stable against periodic pitching moment caused by flapping.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.7
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• pp.661-666
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• 2015

This paper presents control performance improvement by modifying center of gravity (COG) of an underwater robotic platform. To reduce the oscillation or to increase the positioning accuracy, it is important to accurately know the COG of an underwater robotic platform. The COG is determined by the three measured tilting angles of the platform in different postures. The tilting angle is measured while the platform is hanged by two strings. Using coordinate transformation, the plane of intersection is defined from the angle of the platform and the position of the string. The COG of the robotic platform is directly calculated by the intersected point in three defined planes. The measured COG is implemented to the control algorithm that is pre-designed in the previous research, and the empirical result on tilting gives 48.26% improved oscillation performance comparing to the oscillation result with the ideal COG position.

• Journal of Institute of Convergence Technology
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• v.11 no.1
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• pp.33-37
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• 2021

The application of multicopters using a battery is limited by the short endurance due to the low energy density. A propeller is one of crucial components that determine the performance of the multicopter. In the present study, a systematic method for predicting the endurance of multicopters is described. Propeller performance database are constructed using the data from UIUC Propeller Data Site. Using the 'trendline' function of MS Excel software, the performance of the commercial propellers are represented as a function of polynomials. The multicopter's endurance is computed iteratively using Peukert's Law and considering the voltage drop effect. We evaluated the endurance of multicopters that use commercial propellers. The endurance of the multicopter was within the range of 28 min. to 36 min. It is expected that the present method can be utilized for optimal propeller selection for the given multicopters.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1375-1379
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• 2004

Unmanned Helicopter has several abilities such as vertical Take off, hovering, low speed flight at low altitude. Such vehicles are becoming popular in actual applications such as search and rescue, aerial reconnaissance and surveillance. These vehicles also used under risky environments without threatening the life of a pilot. Since a small aerial vehicle is very sensitive to environmental conditions, it is generally known that the flight control is very difficult problems. In this paper, a flight control system was designed for an unmanned helicopter. This paper was concentrated on describing the mechanical design, electronic equipments and their interconnections for acquiring autonomous flight. The design methodologies and performance of the helicopter were illustrated and verified with a linearized equation of motion. The LQG based estimator and controller was designed and tested for this unmanned helicopter.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.763-766
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• 1996

A model helicopter is an unstable, multi-input multi-output nonlinear system exposed to strong disturbances and its system parameters change continually. In this paper, Time Delay Control(TDC) is adopted for these reasons. TDC uses past observation of the system's response and the control input to directly modify the control action rather than adjusting the controller gains leading to a model independent robust controller. TDC can force the plant to follow an appropriate reference model, but the reference model cannot be chosen arbitrarily. In this paper the procedure of choosing a reference model and the performance of the controller are presented.

• Journal of Industrial Technology
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• v.5
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• pp.51-57
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• 1985

The object of this study is in the development of the computer program to predict the performance of rotor in hovering by getting the aerodynamic load acting on blade. For this work the vortex theory was chosen among the aerodynamic theories, blade was replaced by planar vortex panels, and prescribed wake for the wake geometry was selected and then represented by vortex lattices. To get the aerodynamic load on blade, flow was assumed to be incompressible, irrotational and steady, and the surface boundary condition of inviscid flow was used as boundary condition. Then the relationships between this load and flight condition and blade geometry were examined.

• Aerospace Engineering and Technology
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• v.6 no.2
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• pp.236-244
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• 2007

The 40% scaled vehicle of Smart UAV has been developed for the investigation of basic flight characteristics and the verification of flight control algorithm. The similar gimbal hub and drive train with the full scale UAV were implemented and a forced air cooling reciprocating engine was installed. The various kind of tests were conducted for the major components of the vehicle. The important performance and mechanical endurance of the fabricated vehicle were identified by ground and hovering test.