• 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.

• 대한기계학회논문집A
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• 제27권11호
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• pp.1831-1839
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• 2003

This paper deals with design and control of passive multiple trailer systems fer practical applications. Due to cost and complexity of trailer mechanism, passive systems are preferred to active systems in this research. The control objective is to minimize trajectory tracking errors of passive multiple trailers. Three types of passive trailer systems-direct-hooked, three-point, and off-hooked- are discussed in this paper. Trajectory tracking performance and stability issues under constant velocity motion are carried out for three types. Various simulations and experiments have been also performed for these three types. It is shown that the proposed off-hooked trailer system produces better tracking performance than the other types.

• 한국지진공학회논문집
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• 제7권1호
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• pp.17-29
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• 2003

본 연구에서는 수동, 능동, 반능동 및 복합 시스템과 같은 다양한 제어시스템의 효율성을 미국토목학회에서 제시한 지진하중을 받는 첫번째 벤치 마크 사장교을 이용해 조사하였다. 이 벤치마크 문제는 2003년 완공 예정으로 미국 Mississippi주에 건설중인 Bill Emerson Memorial교를 대상 구조물로 고려하였다. Bill Emerson Memorial 교는 New Madrid 지진구역에 위치하고 Wississippi 강을 횡단하는 주요 교량이라는 점 때문에 설계 단계에서부터 내진설계가 고려되었다. 사장교의 상세한 설계도면에 기초해 교량의 복잡한 거동을 나타낼 수 있는 3차원 선형모델과 각 제어시스템의 성능을 평가하기 위한 18개의 평가기준이 개발되었다. 본 연구에서는 네 종류의 수동제어 시스템, 한 종류의 능동제어 시스템, 두 종류의 반능동제어 시스템 밑 세 종류의 복합제어 시스템이 고려되었다. 수치해석 결과 모든 제어시스템은 지진하중을 받는 벤치마크 사장교의 응답을 감소시켰다. 그러나, 수동제어 시스템의 경우에는 뛰어난 제어성능을 얻기 위해서 다른 제어시스템에 비해 커다란 제어력을 필요로했다. 강인성에 관한 수지해석 결과에 따르면, 수동, 반능동 및 복합제어 시스템이 구조물 강성의 불확실성에 대해 강인함을 보였다. 따라서, 반능동 및 복합제어 시스템이 토목구조물과 같은 대형구조물의 실제 적용에 보다 적절하다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 추계 학술발표회논문집
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• pp.387-394
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• 2003

A compromise between passive and active control systems has been developed recently in the form of semi-active control systems. Semi-active control systems maintain the reliability of passive control systems while taking advantage of the adjustability of an active control system. This paper presents the results of an experimental study to evaluate the performance of a semi-active orificed fluid damper. The semi-active orificed fluid damper considered is a two-stage damper with normally open solenoid valve. Through a series of experimental tests, characteristics and performance of the damper is investigated.

• 한국안전학회지
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• 제32권6호
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• pp.81-88
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• 2017

This study deals with the optimal design of a hybrid control system composed of a combination of active control system and passive control system for effective seismic performance improvement of two adjacent structures. The proposed hybrid control system adopts a configuration of installing an active control device in one building and connecting two adjacent structures with a passive control device so that the one-side active control force can be bi-directionally applied to both buildings through the passive connecting devices. In order to derive the optimal performance of the proposed system, the design parameters of the passive and active control systems were searched using the genetic algorithm. Numerical simulations of 10-story and 8-story buildings have been performed to verify the effectiveness of the proposed technique. For the purpose of comparison, the conventional independent control system with two identical active control systems being installed separately for each structure was also optimally designed and its seismic response has been evaluated as well. From the comparative results of the two control systems, it is demonstrated that the proposed hybrid control system requires larger control force for its one-side active control device than the conventional independent control system does for each of both-side active devices, but quite less than the total control force required for both-side devices of the independent control system, while maintaining similar seismic performance. Therefore, the proposed system is more economical and reliable than the conventional independent control system with two identical active devices.

• Smart Structures and Systems
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• 제4권6호
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• pp.741-757
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• 2008

The research field of structural control has evolved from the development of passive devices since 1970s, through the intensive investigation on active systems in 1980s, to the recent studies of semi-active control systems in 1990s. Currently semi-active control is considered most promising in civil engineering applications. However, actual implementation of semi-active devices is still limited due mainly to their system maintenance and associated long-term reliability as a result of power requirement. In this paper, the concept of functionally upgraded passive devices is introduced to streamline some of the state-of-the-art researches and guide the development of new passive devices that can mimic the function of their corresponding semi-active control devices for various applications. The general characteristics of this special group of passive devices are discussed and representative examples are summarized. Their superior performances are illustrated with cyclic and shake table tests of two example devices: mass-variable tuned liquid damper and friction-pendulum bearing with a variable sliding surface curvature.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2006년도 학술발표회 논문집
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• pp.401-408
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• 2006

An optimum design method for hybrid control systems is proposed in this study. By considering both active and passive control systems as a combined or a hybrid system, the optimization of the hybrid system can be achieved simultaneously. In the proposed approach, we consider design parameters of active control devices and the elements of the feedback gain matrix as design variables for the active control system. Required quantity of the added dampers are also treated as design variables for the passive control system. In the proposed method, the cost of both active and passive control devices, the required control efforts and dynamic responses of a target structure are selected as objective functions to be minimized. To effectively address the multi-objective optimization problem, we adopt a preference-based optimization model and apply a genetic algorithm as a numerical searching technique. As an example to verify the validity of the proposed optimization technique, a wind-excited 20-storey building with hybrid control systems is used and the results are presented.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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• pp.97-99
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• 2009

Bilateral teleoperation systems, connected to computer networks such as Internet have to deal with the time delay varying depending on factors such as congestion, bandwidth or distance. And the entire system is easy to become unstable due to irregular time delay. Passivity concept has been using as a framework to solve the stability problem in bilateral control of teleoperation. Acontrol scheme for teleoperation systems with varying time delay is proposed based on a passivity concept is proposed in this paper. One approach makinguse of the characteristic impedances is proposed to achieve a passive control. Since passive control does not mean that the system performance will be acceptable, another transmission scheme which focuses on both the passive feature and the acceptable performance is configured for varying time delay in this paper. The tracking performance has been proved through the computer simulation for varying time delay bilateral teleoperation system using Matlab Simulink.

• 한국자동차공학회논문집
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• 제9권3호
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• pp.100-107
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• 2001

The main goals of the automotive suspension systems are to isolate roadway unevenness from the tire and to improve vehicle stability. To overcome the performance limitation of the passive systems the active systems which completely replace the passive spring and damper elements with a force generating actuator has been studied. However, application of the system has been limited because it has required a significant amount of power. Recently, alternative systems which retain passive elements but include active elements have been developed to reduce the power required. Those systems are mostly focused on the control system which compresses the spring-damper directly. In this study, a new type of power efficient control system which makes the spring-damper unit slide in side way is studied. After constructing the control system including dynamic modeling and motion control, two types of alternative control systems are compared in view of power consumption and dynamic attitudes such as roll responses as well as heave responses. Also, a half car bond graph model is developed to show clearly the significant differences in performances between two control systems.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1559-1564
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• 2003

In this paper, a control method is presented to improve performance of haptic display on a passive haptic device equipped with passive actuators. In displaying a virtual wall with the passive haptic device, an unstable behavior occurs with excessive actions of brakes due to the time delay mainly arising from the update rate of the virtual environment and force approximation originated from the characteristics of the passive actuators. The previous T.D.P.C. (Time Domain Passivity Control) method was not suitable for the passive haptic device, since a programmable damper used in the previously introduced T.D.P.C. method easily leads to undesirable behaviors. A new passivity control method is evaluated with considering characteristics of the passive device. First, we propose a control method which is designed under the analysis of the passive FME (Force Manipulability Ellipsoid). And then a passivity control scheme is applied to the proposed control method. Various experiments have been conducted to verify the proposed method with a 2-link mechanism.