• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.42 no.1
• /
• pp.67-75
• /
• 2014

A full-scale static test for a composite structure small aircraft (KC-100) was conducted in the KARI. The test includes 15 full-scale test and 7 local test conditions. Test requirements with test schedule, test article with dummy structures, test load generation, test system, and equipment are introduced for the test. Test load data of the 1st test condition(U1) was analyzed to evaluate an accuracy of load control for the test. The analysis results show that load data obtained during test were within tolerance of Static Null Pacing Error(SNPE) and the error value of load control was 8.6N. The error of load controls for the full-scale static test using dozens of actuators was calculated by a method suggested by authors. Test data for all other test conditions is also shown in this paper. Finally, reactions measured from restraint system of the U1 test condition show that the reaction changes as load increment. The factors which may change the change of reactions for a full-scale static test are introduced in this study.

• Journal of the Korean Institute of Telematics and Electronics T
• /
• v.35T no.3
• /
• pp.87-95
• /
• 1998

This paper presents the method for the automatic tuning of a design weighting polynomial parameter of a generalized minimum-variance stochastic self tuning controller which adapts to changes in the system parameters with time delays and noises. The self tuning effect is achieved through the recursive least square algorithm at the parameter estimation stage and also through the Robbins-Monro algorithm at the stage of optimizing a design weighting polynomial parameters. The proposed self tuning method is simple and effective compared with other existing self tuning methods. The computer simulation results are presented to illustrate the procedure and to show the performance of the control system.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.4
• /
• pp.315-320
• /
• 2010

To improve not only the basic performance but also the fail-safe performance, power consumption of the main landing gear for helicopters, a semi-active control landing gear using hybrid MR damper, was introduced in this paper. This damper of the configuration to install a permanent magnet in a electromagnet MR damper, was designed by the trade-off study on permanent magnet location and a magnet field analysis. Force control algorithm which keep the sum of air spring force and damping force at a specified value during landing, was used for the controller. The drop simulations using ADAMS Model for this semi-active control landing gear, were done. The improvement of the preceding performances as the result to evaluate the landing performance by the simulations, has been confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.7
• /
• pp.256-262
• /
• 2016

This study performed the back-pressure cold forging analysis to minimize the non-forming area of gear teeth for the output hub and reaction hub in automatic transmission. Two important factors of the back-pressure cold forging process, the load of the punch and the backup force applied to the sleeve, were determined through displacement control analysis. The non-forming area of the gear teeth was compared with both cases of the displacement control analysis and load control analysis, and their solution is similar to the measuring result of a real workpiece. The results show that the load of the punch is dependent on the reduction area of the workpiece, and the backup force applied to the sleeve is determined with regard to the cross-section-area of sleeve. This analysis procedure can be useful and effective in determining the manufacturing condition of the back-pressure cold forging process to minimize the non-forming area.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.6 no.4
• /
• pp.51-63
• /
• 2002

This paper presents a hybrid control strategy for seismic protection of a benchmark cable-stayed bridge, which is provided as a testbed structure for the development of strategies for the control of cable-stayed bridges. This benchmark problem considers the cable-stayed bridge that is scheduled for completion in Cape Girardeau, Missouri, USA in 2003. Seismic considerations were strongly considered in the design of this bridge due to the location of the bridge in the New Madrid seismic zone and its critical role as a principal crossing of the Mississippi river. Based on detailed drawings of this cable-stayed bridge, a three-dimensional linearlized evaluation model has been developed to represent the complex behavior of the bridge. A set of eighteen evaluation criteria has been developed to evaluate the capabilities of each control strategy. In this study, a hybrid control system is composed of a passive control system to reduce the earthquake-induced forces in the structure and an active control system to further reduce the bridge responses, especially deck displacements. Conventional base isolation devices such as lead rubber bearings are used for the passive control design and Bouc-Wen model is used to simulate the nonlinear behavior of these devices For the active control design, ideal hydraulic actuators are used and on $H_2$/LQG control algorithm is adopted. Numerical simulation results show that the performance of the proposed hybrid control strategy is quite effective compared to that of the passive control strategy and slightly better than that of the active control strategy. The hybrid control method is also more reliable than the fully active control method due to the passive control part. Therefore, the proposed hybrid control strategy can effectively be used to seismically excited cable-stayed bridges.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.47 no.4
• /
• pp.61-68
• /
• 2010

Appling high technology of aerospace to automobile, so it is able to progress safety which is a goal of future automobile and to approach development of self-control automobile. This is realized dynamic model of airplane at DFCS(Digital Flight Control System). The DFCS calculates control values for self-control flight. If this high technology applies to automobile, then it is able to be maneuvered automobile like UAV's self-control flight. In this paper is reanalyzed automobile dynamic applied load control model used high-tech of airplane. It analyzes riding comfortable according to movement of automobile using the load control model, presents method of solution for improvement riding comfortable and presents example of self-control system used the load control model for self-control driving.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.50 no.11
• /
• pp.791-800
• /
• 2022

The number and locations of force generators and their force directions of Active Vibration Control System(AVCS) are important to maximize the airframe vibration reduction performance of helicopters. The present AVCS simulation using an exhaustive test method attempts to determine the best number and locations of force generators and their force directions for maximization of the airframe vibration reduction performance of UH-60A helicopter at 158 knots. The 4P hub vibratory loads of the UH-60A helicopter are calculated using DYMORE II, a nonlinear multibody dynamics analysis code, and MSC.NASTRAN is used to predict the vibration responses of the UH-60A airframe. The AVCS framework with an exhaustive test method is constructed using MATLAB Simulink. As a result, when applying AVCS with the optimal combination of the force generators, the 4P airframe vibration responses of UH-60A helicopter are reduced by from 19.35% to 98.07% compared to the baseline results without AVCS.

• Magazine of the Korea Concrete Institute
• /
• v.10 no.1
• /
• pp.143-151
• /
• 1998

최근들어 반복하중에 의한 철근콘크리트 구조물의 손상이 자주 발견되고 있으며 교량 등의 구조물 등은 때때로 과적차량에 의한 초과하중을 받아 이러한 피로손상이 심화되고 있다. 본 연구에서는 이러한 반복 하중을 받는 철근 콘크리트보의 누적피로손상에 대한 실험적 연구룰 수행하여 피로하중에 의한 철근콘크리트보의 손상과정을 규명하였다. 실험 변수를 전단철근의 양과 반복되는 하중의 크기 및 반복횟수로 하여 실험부재를 제작하였으며, 하중제어에 의한 휨시험법에 의해 3Hz의 반복하중을 시편에 재하하였다. 사인장 균열하중과 사인장 균열 후 반복하중에서의 보의 손상누적거동 즉 처짐. 전단철근의 변형도, 에너지 손실 등의 변화를 실험적으로 평가하였으며, 이를 통하여 반복하중에 의한 누적손상에 의해 철근 콘크리트보의처짐 및 전단변형도가 초기하중상태에서는 급격히 증가하다가 이후 점진적으로 증가하는 것을 규명하였다. 본 연구의 결과는 사용하중상태에서 점진적으로 발생할 수 있는 피로손상의 누적과정을 기술하여 주고 있다.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.37 no.5
• /
• pp.22-33
• /
• 2000

Since the heavy-duty power manipulator generally has high ratio gear reducers at its joints, its dynamic characteristics is much slower than that of the master manipulator and it is likely to encounter the saturation in the input magnitude when it is used as the slave manipulator in telemanipulation systems. This paper proposes a force reflecting and compliant control scheme for the heavy-duty power telemanipulator. The main advantage of the proposed scheme is that it provides a precise position and compliant control performance for a telemanipulator with control input saturation. The stability of the proposed scheme is analyzed and a series of experiments shows its performance.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.5
• /
• pp.487-495
• /
• 2012

The yaw control, a major part of the wind turbine, is closely related to the efficiency of electric power production and the mechanical load. The yaw error, which results from the nacelle not being appropriately aligned in the wind direction, not only decreases the power output but also reduces the lifetime of the wind turbine as a result of large fatigue loads. However, the yawing rate cannot be increased indefinitely because of constraints on mechanical loads. This paper investigates the characteristics of an active yaw control system, the basic principle of the system, and mechanical loads around the yaw axis during yawing.