• 한국소음진동공학회논문집
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• 제14권6호
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• pp.503-511
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• 2004

본 연구에서는 푸리에 모델, 확률 모델, 그리고 Newmark 설계 스펙트럼 방법과 같은 응답예측 모델을 사용하여 속도의존형 감쇠장치에 의해 제어되는 구조물의 응답과 제어기의 최대제어력을 예측하였다. 이를 위해, 유사 속도로부터 실제 속도를 예측하는 방법이 제안되었으며, 이 방법은 감쇠장치에 의해 증가되는 감쇠비의 실제속도에 대한 효과를 고려한다. 시간이력해석결과는 정확한 최대제어력을 예측하기 위해서는 실제속도가 사용되어야 하며, 제안된 방법에 의해 수정된 Newmark 설계 스펙트럼이 가장 전 주기구간에 걸쳐 정확한 예측 값을 산정함을 보여준다.

• 전기학회논문지
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• 제62권6호
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• pp.852-862
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• 2013

This paper proposes a target tracking control method for wheeled mobile robots with nonholonomic constraints by using a backstepping-like feedback linearization. For the target tracking, we apply a vision system to mobile robots to obtain the relative posture information between the mobile robot and the target. The robots do not use the sensors to obtain the velocity information in this paper and therefore assumed the unknown velocities of both mobile robot and target. Instead, the proposed method uses only the maximum velocity information of the mobile robot and target. First, the pseudo command for the forward linear velocity and the heading direction angle are designed based on the kinematics by using the obtained image information. Then, the actual control inputs are designed to make the actual forward linear velocity and the heading direction angle follow the pseudo commands. Through simulations and experiments for the mobile robot we have confirmed that the proposed control method is able to track target even when the velocity sensors are not used at all.

• International Journal of Railway
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• 제1권2호
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• pp.64-71
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• 2008

The quality of track-bed fills of railways has been controlled by field measurements of density $({\gamma}_d)$ and the results of plate-load tests. The control measures are compatible with the design procedures whose design parameter is $k_{30}$ for both ordinary-speed railways and high-speed railways. However, one of fatal flaws of the design procedures that there are no simple laboratory measurement procedures for the design parameters ($k_{30}$ or, $E_{v2}$ and $E_{v2}/E_{v1}$) in design stage. A new quality control procedure, in parallel with the advent of the new design procedure, is being proposed. This procedure is based upon P-wave velocity involving consistently the evaluation of design parameters in design stage and the field measurements during construction. The Key concept of the procedure is that the target value for field compaction control is the P-wave velocity determined at OMC using modified compaction test, and direct-arrival method is used for the field measurements during construction. The procedure was verified at a test site and the p-wave velocity turned out to be an excellent control measure. The specifications for the control also include field compaction water content of OMC${\pm}$2% as well as the p-wave velocity.

• Journal of Power Electronics
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• 제15권1호
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• pp.246-255
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• 2015

This paper presents experimental results and its assessment of a variable-speed wind power generation system (VSWPGS) using permanent magnet synchronous generator (PMSG) and boost chopper circuit (BCC). Experimental results are obtained by a test bench with a wind turbine emulator (WTE). WTE reproduces the behaviors of a windmill by using servo motor drives. The mechanical torque references to drive the servo motor are calculated from the windmill wing profile, wind velocity, and windmill rotational speed. VSWPGS using PMSG and BCC has three speed control modes for the level of wind velocity to control the rotational speed of the wind turbine. The control mode for low wind velocity regulates an armature current of generator with BCC. The control mode for middle wind velocity regulates a DC link voltage with a vector-controlled inverter. The control mode for high wind velocity regulates a pitch angle of the wind turbine with a pitch angle control system. The hybrid of three control modes extends the variable-speed range. BCC simplifies the maintenance of VSWPGS while improving reliability. In addition, VSWPGS using PMSG and BCC saves cost compared with VSWPGS using a PWM converter.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1909-1914
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• 2004

Passive velocity field control (PVFC) was previously developed for fully mechanical systems, in which the motion task was specified behaviorally in terms of a velocity field, and the closed-loop was passive with respect to a supply rate given by the environment input. However the PVFC was only applied to a single manipulator, the proposed control law was derived geometrically, and the geometric and robustness properties of the closed-loop system were also analyzed. In this paper, we propose a method to apply a decentralized control algorithm to cooperative 3-wheeled mobile robots whose subsystem is under nonholonomic constraints and which convey a common rigid object in a horizontal plain. Moreover it is shown that multiple robot systems ensure stability and the velocities of augmented systems convergence to a scaled multiple of each desired velocity field for cooperative mobile robot systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.247-250
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• 2003

In this paper, we propose a robust controller for motion control of n-link robot manipulators using visual feedback. The desired joint velocity and acceleration is obtained by the feature-based visual systems and is used in the joint velocity control loop for trajectory control of the robot manipulator. We design a robust controller that compensates for bounded parametric uncertainties of robot dynamics. The stability analysis of robust joint velocity control system is shown by Lyapunov Method. The effectiveness of the proposed method is shown by simulation results on the 5-link robot manipulators with two degree of freedom.

• 자동차안전학회지
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• 제9권2호
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• pp.26-32
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• 2017

This paper presents the lateral stability criteria for integrated chassis control. To determine the intervention timing of chassis control system, the lateral stability criteria is needed. The proposed lateral stability criteria is based on velocity-yawrate gain domain to determine whether vehicle is stable. If the yawrate gain violates the proposed criteria, the stability of the vehicle is considered as unstable. Characteristic velocity and critical velocity are employed to distinguish lateral stability criteria. The inside of the two boundaries is stable and the outside is unstable. If yawrate gain of vehicle violates the lateral stability criteria, the chassis control begin to intervene. To validate the lateral stability criteria, both computer simulations and vehicle test are conducted with respect to circular turn scenario. The proposed lateral stability criteria makes it possible to reduce intervention of chassis control system.

• Wind and Structures
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• 제17권4호
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• pp.399-417
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• 2013

The structural vibration suppression with active constrained layer damping (ACLD) was widely studied recently. However, the literature seldom concerned with the vibration control on flow-induced vibration using active constrained layer. In this paper the wind induced vibration of cantilevered beam is analyzed and suppressed by using random theory together with a velocity feedback control strategy. The piezoelectric material and frequency dependent viscoelastic layer are used to achieve effective active damping in the vibration control. The transverse displacement and velocity in time and frequency domains, as well as the power spectral density and the mean-square value of the transverse displacement and velocity, are formulated under wind pressure at variable control gain. It is observed from the numerical results that the wind induced vibration can be significantly suppressed by using a small outside active voltage on the constrained layer.

• 제어로봇시스템학회논문지
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• 제12권4호
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• pp.380-388
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• 2006

A noisy behavior of the time domain passivity controller during the period of low velocity is analyzed. Main reasons of the noisy behavior are investigated through a simulation with a one-DOF (Degree of Freedom) haptic interface model. It is shown that the PO/PC is ineffective in dissipating the produced energy when the sign of the velocity, which is numerically calculated from the measured position, is suddenly changed, and when this velocity is zero. These cases happen during the period of low velocity due to the limited resolution of the position sensor. New methods, ignoring the produced energy from the velocity sign change, and holding the control force while the velocity is zero, are proposed for removing the noisy behavior. The feasibility of the developed methods is proved with both a simulation and a real experiment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.60-65
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• 2003

In this study, for estimating responses of a controlled structure and determining the maximum control force of velocity-dependent damping devices, three estimation models such as Fourier envelope convex model, probability model, and Newmark design spectrum are used. For this purpose, a procedure proposed by Gupta (1990) for estimating spectral velocity using pseudo-spectral velocity which is given by the estimation models is used and modified to consider the effects of increased damping ratio by the damping device. Time history results indicate that Newmark design spectrum gives the best estimation of maximum control force for over all period structures.