• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.11
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• pp.1104-1111
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• 2008

The supersonic advanced trainer based on digital flight-by-wire flight control system uses aircraft flight information such as altitude, calibrated airspeed and angle of attack to calculate flight control law, and this information is measured by IMFP(Integrated Multi-Function Probe) equipment. The information has triplex structure using three IMFP sensors. Final value of informations is selected by mid-value selection logic to have more flight data reliability. As the result of supersonic flight test, pitch oscillation is occurred due to IMFP noise when altitude hold autopilot mode is engaged. This tendency may affect stability and handling quality of an aircraft during autopilot mode. This paper addresses autopilot control law design to remove pitch oscillation and these control laws are verified by non-real time simulation and flight test. Also, pitch response characteristics of pitch attitude hold autopilot mode is improved by upgrading the control law structure and feedback gain tuning during bank turn.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.34-34
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• 1998

차세대 비행체가 갖추어야 할 요건으로 다양한 작동 범위에서 다목적으로 사용될 수 있어야 한다는 점이다. 비행체는 작전시 초음속으로 순항해야 하며, 폭탄으로 손상된 비행장에서도 이륙하여 작동할 수 있도록 짧은 이륙과 착륙 거리를 가져야 하기 때문에 현재 비행체보다 더 큰 받음각에서 작동하여 비행시 뛰어난 기동성을 가져야 한다. 제어력을 향상시키기 위해서 받음각과 동압에 의존하지 않고 큰 제어 모멘트를 제공하는 차세대 방법은 엔진의 배기가스를 원하는 비행 방향으로 제어하는 것으로 이러한 방법을 추력 편향 제어(Thrust Vector Control)라고 한다. 기존 공력에 의한 비행 자세제어 방법은 속도의 2승에 비례하는 제어력을 발생하지만, 실속을 피해야하기 때문에 공기력을 이용한 날개 및 비행체의 받음각에 한계가 있어 비행체의 선회능력을 제한하며 고공에서 저속비행 하는 경우에는 공기의 밀도가 낮고 동압이 작게 작용하여 선회능력은 낮아진다. 그러나, 추력 편향 장치는 공력을 이용하지 않고 추력을 이용하기 때문에 실속에 의한 제한이 없어 큰 받음각(70$^{\circ}$-90$^{\circ}$)으로 선회할 수 있어 월등한 기동성을 발휘할 수 있다. 이러한 추력 편향 장치 중 제트 베인형은 소형화가 가능하고, 하나의 노즐로 수직, 수형 및 횡 방향의 3축 제어를 할 수 있어 많이 사용되고 있다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.5
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• pp.527-534
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• 2015

This paper presents an integrated chassis control with electronic stability control (ESC) and active front steering (AFS) under lateral force constraint on AFS. The control yaw moment is calculated using a sliding mode control. The tire forces generated by ESC and AFS are determined using weighted pseudo-inverse based control allocation (WPCA) in order to generate the control yaw moment. On a low friction road, AFS is not effective when the lateral tire forces of front wheels are easily saturated. To solve problem, the lateral force of AFS is limited to its maximum and the braking of ESC is applied with WPCA. To evaluate the effectiveness of the proposed method, a simulation was performed on the vehicle simulation package, $CarSim^{(R)}$. From the simulation, it was verified that the proposed method could enhance the maneuverability and lateral stability if the lateral force of AFS exceeds its maximum.

• Journal of Advanced Navigation Technology
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• v.15 no.2
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• pp.181-188
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• 2011

A small UAVs(Unmaned Aerial Vehicles) have limited by the payload capacity which requires miniaturization of a navigation system. In this paper, the performance of the lightweight and small sized AHRS(Attitude Heading Reference System), which is self-developed, is evaluated at low acceleration environment. The designed AHRS adopts the commercial low-cost MEMS sensors. A quaternion-based attitude calculation method, which eliminates singularity with relatively simple algebra, is used. In an attitude correction algorithm, the Kalman filter is used with accelerometers and magnetometers combined. The fabricated AHRS is also evaluated with reference to a COTS(Commercial Off-The-Shelf) AHRS which reports a number of successful applications to a small UAVs. The test results show that the measurements from the fabricated AHRS provide proper attitude output data with acceptable amount of differences(horizontal axis 0.5$^{\circ}$, vertical axis 1.5$^{\circ}$) in test environment.

• 전자공학회논문지 IE
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• v.45 no.4
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• pp.11-18
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• 2008

This study is implementation of attitude control system(ACS - Attitude Control System). for a multi legs robot. This study designs H/W of Inertial Measurement Unit (IMU) and attitude control algorithm S/W. Compare performance with Mtx and MTx in order to verify action performance of this system after implementation, and will verify a system integrated IMU of a multi-legs robot. ACS uses Gyro and an accelerometer and an earth magnetism sensor, and it is a system controlling a roll, pitch angle attitude of an object. Generally, low price MEMS is difficult to calculate a correct situation of an object as an error occurs severely the Inertial sensor. This study implements IMU in order to develop ACS as use MEMS, accelerometer, Gyro sensor and earth magnetism sensor. Design algorithm each a roll, pitch, yaw attitude guaranteeing regular performance, and do poling in a system as include an attitude calculation program in an IMU system implemented. Mixed output of Gyro and an accelerometer, and recompensed a roll, pitch angle, and loaded in this study on a target platform in order to implement the ACS which guaranteed performance more than a continuously regular level, and operated by real time, and did porting, and verified.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.4
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• pp.327-334
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• 2013

In August 2012 the first CanSat competition was hosted by the Satellite Research Center of KAIST under auspice of the Ministry of Education, Science and Technology. The present authors team won the first prize in the university session. In this paper the overall procedure of the CanSat project presented from the conceptual design stage to the final launch test. As the compulsory mission CanSat should send GPS data and attitude information to the ground station which in practice was performed via Bluetooth channel. In addition our CanSat is designed to trace the sun for the solar panels supplying electric power of satellite. IMU and servo motors are used for the attitude control in order that the solar sensor of the CanSat is always direct towards the sun. Launching of CanSat was simulated by dropping from a balloon at the height of around 150m via parachute. Launching test results showed that the attitude control of the CanSat and its solar sensing function were successful.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.25-29
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• 2007

Minimization of conventional propulsion device has been studied for altitude control of micro satellite. We studied micro nozzle performance and found higher significant loss for a micro nozzle with smaller nozzle throat diameter. To overcome this loss, we proposed thermal transpiration based micro propulsion system. This new system has no moving parts and can control flow by temperature gradient, and this can be an option for potential new micro propulsion system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.2
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• pp.172-178
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• 2015

The control moment gyroscope(CMG) which is well known as an effective high-torque-generating device is applicable to space vehicles, airplanes, ships, automobiles, robotics, etc. for attitude stabilization and maneuver. This paper deals with the overall details of 100Nm-class CMG development for various industrial applications, and provides the activities and results associated with the CMG system-level requirement analysis, the motor subsystem design/manufacturing/integration, the construction of ground support equipment, and the performance test and evaluation. The performance test reveals that the CMG generates the torque output more than 120Nm in as-designed operation of spin motor and gimbal motor.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.6 s.144
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• pp.566-574
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• 2005

Reduction of a ship's rolling is the most important performance requirement for improving the safety of the crew on board and preventing damage to cargos as well as improving the comfort of the ride. A mass driving anti-rolling system (MO-ARS) might be one candidate of several systems against the ship's rolling. As the movable range of the mass on the ship is finite, the control system must include restriction on the mass position to protect the device and the ship. This restriction usually causes windup phenomenon and control performance is deteriorated seriously. Two control algorithms, anti-windup control and saturated sliding mode control, are studied in this paper. Control performance and robustness problem are checked out by numerical simulations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3869-3875
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• 2012

In this study, mathematical modeling and experimental analysis were executed in order to evaluate the valve dynamic characteristics when the hydraulic pressure applied. High pressure on the master cylinder effects on the valve dynamic characteristics have been analyzed. The pulsation pressure generated in hydraulic systems causes noise, vibration and odd effect to the system. To reduce the pulsation pressure, high frequency PWM control of 20KHz was attempted. Also, an analytic method is proposed for the resultant forces of electromagnetism and hydraulic pressure generated in the real vehicle electro stability program. Consequently, results of solenoid valve dynamic characteristics analysis derived in the study can be confirmed criteria for the optimal control of electronic stability program system.