• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.3
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• pp.251-257
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• 2012

The flight controller should meet the flying qualities, stability margins, and time response requirement according to the class of a target aircraft or UAV. Classical design process of PID controller is a very time consuming process and needed trial and erros. The best way is to apply the multi-disciplinary optimization algorithm to meet the numerous constraints of controller requirements. This paper presents how multi-objective parameter optimization (CONDUIT) can be used to determine many design parameters of lateral stability and augmentation system for roll and heading controller of the small UAV. To verify the effectiveness of applying the optimization method, designed controller using optimization are compared with the baseline controller that is designed only considering the time responses.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.6
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• pp.17-23
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• 2012

An integrated dynamic control (IDCF) with an active front steering system and an active rear braking system is proposed and developed in this study. A fuzzy logic controller is applied to calculate the desired additional steering angle and desired slip of the rear inner wheel. To validate IDCF system, an eight degree of freedom, nonlinear vehicle model and a sliding mode wheel slip controller are also designed. Various road conditions are used to test the performance. The results show that the yaw rate of IDCF vehicle followed the reference yaw rate and reduced the body slip angle, compared with uncontrolled vehicle. Thus, the IDCF vehicle had enhanced lateral stability and controllability.

• Journal of the Korea Convergence Society
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• v.8 no.12
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• pp.291-298
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• 2017

In recent years, the increase of secondary controls within vehicles requires a mechanism to integrate various controls into a single device. This paper presents control performance of an integrated magnetorheological (MR) haptic device which can adjust various in-vehicle comfort instruments. As a first step, the MR fluid-based haptic device capable of both rotary and push motions within a single device is devised as an integrated multi-functional instrument control device. Under consideration of the torque and force model of the proposed device, a magnetic circuit is designed. The proposed MR haptic device is then manufactured and its field-dependent torque and force are experimentally evaluated. Furthermore, an inverse model compensator is synthesized under basis of the Bingham model of the MR fluid and torque/force model of the device. Subsequently, haptic force-feedback maps considering in-vehicle comfort functions are constructed and interacts with the compensator to achieve a desired force-feedback. Control performances such as reflection force are experimentally evaluated for two specific comfort functions.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.6
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• pp.958-966
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• 2010

In this paper, we have proposed a integrated dynamic control architecture in 6WD(wheel drive)/6WS(wheel steering) vehicle for military applications. Since 6WD/6WS vehicle has inherent redundancy, the input variables to make any desired vehicle motion can not be determined uniquely. Therefore, optimal distribution method of tire forces is introduced, which is based on workload of each tire. Simulation result shows that this is effective for the energy minimization and dynamic performance enhancement. We also suggest how the integrated control with any failure mode should be reconstructed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.1
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• pp.85-92
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• 2005

The motion of flexseal bearing for movable nozzle has inherent nonlinear characteristics due to floating rotational center and compression by combustion pressure of solid motor. To perform precise attitude control in spite of these characteristics, the TVC actuation system requires counter potentiometer as an extra position feedback sensor of movable nozzle to form a compensated control loop. The prototype TVC actuation system, test equipments and compensated controller are newly designed, manufactured and tested in consideration of counter potentiometer. On the basis of integration test, the inherent characteristics of movable nozzle and control characteristics of its TVC actuation system are analyzed and summarized in this paper.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.216-217
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• 2005

This paper presents an integrated navagation control concept for underwater vehicles under high speed navigation circumstance. First of all, in order to control an underwater vehicle with respect to automatic navigation, an integrated navigation control method is suggested in view of synchronous control for course keeping, diving and depth control. An exact nonlinear model equation with six-degree-of-freedom is derived for control algorithm. To identify various hydrodynamic coefficients of the equation, an experimental approach is introduced and results are demonstrated for MANTA type model.

• The Journal of Aerospace Industry
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• s.65
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• pp.89-106
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• 2003

항공기의 자동 착륙 알고리즘을 위한 고 정밀 유도방식에 IBLS(Integrity Beacons Landing System)나 MLS(Microwave Landing System)와 같은 유도 제어 방식을 사용하여 유인 항공기나 무인 항공기의 유도 착륙에 사용하고 있다. 당 연구에서는 무인항공기의 자동 착륙을 위한 실제적인 요구사항들이 분석되었고, 자동 착륙 유도장치로 IBLS와 MLS가 선택되어 각각의 기능과 특성들이 수학적으로 모델링 되었다. 또한 고전제어와 최적제어의 2가지 방식으로 무인항공기의 자동 착륙을 통제하기 위한 autopilot이 설계되어 그 유효성과 특징들이 분석되었다. IBLS, MLS, autopilot, 그리고 이러한 자동 착륙 유도제어 시스템이 적용되는 대상체인 무인항공기와 대기환경 및 외란에 대한 수학적 모델들은 Simulink와 ANSI C를 사용하여 단위 S/W 모듈들로 작성되었고, 여기에 GUI모듈이 추가되어 하나의 통합 시뮬레이션 S/W가 완성되었다. 모의시험평가는 총 2단계로 구성되었는데, 대기 외란이 주어졌을 때 IBLS와 MLS의 유효성을 1차적으로 검증하였고, 2단계 모의수치실험에서는 MLS 유도센서 방식에 따른 고전제어기 및 최적제어기의 항공기 종 방향 운동에 대한 강인성 비교를 시도하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.2
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• pp.15-20
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• 2012

This study is to propose and develop an integrated dynamics control system to improve and enhance the lateral stability and handling performance. To achieve this target, we integrate an AFS and a 4WS systems with a fuzzy logic controller. The IDCS determines active additional steering angle of front wheel and controls the steering angle of rear wheel. The results show that the IDCS improves the lateral stability and controllability on dry asphalt and snow paved road when double lane change and step steering inputs are applied. Yaw rate of the IDCS vehicle tracks reference yaw rate very well and body slip angle is reduced about by 50%. Response time of the IDCS vehicle is also decreased.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.5
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• pp.22-27
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• 2022

An integrated front steering system and front brake system (FSFB) is developed to improve the stability and controllability of an SUV. The FSFB simultaneously controls the additional steering angle and front brake pressure. An active front steering system (AFS) and an active front brake system (AFB) are designed for comparison. The results show that the FSFB enhances the lateral stability and controllability regardless of road and running conditions compared to the AFS and AFB. As a result, the yaw rate of the SUV tracks the reference yaw rate, and the side slip angle decreases. In addition, brake pressure control is more effective than steering angle control in improving the stability and steerability of the SUV on a slippery road. However, this deteriorates comfort on dry or wet asphalt.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.5
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• pp.401-408
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• 2017

This paper describes development and validation processes of a low-cost hardware based flight control computer designed for multi-rotor UAVs. The developed flight control computer controls multi-rotors stable and can handle complex flight missions using an integrated high-performance Linux computer. A complementary filter generates a navigation solution with 500 Hz, and a proposed observer significantly reduces measurement noise. A control algorithm utilizes a feed-forward term computed by a three-dimensional curve fitting method, and it increases tracking performance. The developed flight control system has been fully tested through several test flights, and it can apply to real flight environments.