• 한국통신학회:학술대회논문집
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• 한국통신학회 1983년도 추계학술발표회논문집
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• pp.112-117
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• 1983

In this paper, a functional m-redundant system, which is me-fault tolerant, is defined based on the graph-theory. This system is designed to be t fault-diagnosable by comparing its unit's outcomes without additive test functions, and so, the system down for diagnosis is not needed. the diagnostic model for this system is presented and this effectively uses system's redundancy. It is shown that this model can be converted into Preparata's model. Thus, the diagnostic characteristics of a functional m-redundant system is analyzed by the methods originated by Preparata et al..

• 한국산업정보학회논문지
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• 제12권1호
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• pp.80-86
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• 2007

The concept of the coverage has been played an important role in the area of reliability evaluation of a system. The widely used measures of reliability include the m time between failures, the availability and so on. In this paper, we propose an estimator of the coverage probability in a redundant system with a control unit and investigate some moments of the proposed estimator. And assuming exponential distribution of all units, we conduct a simulation study for calculating the estimates of the coverage probability and its confidence bounds. An example of evaluating the availability of an optical transportation system is illustrated.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.116.5-116
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• 2001

When inertial navigation system(INS) employ more sensors that mutually orthogonal sets to three, the redundant sensor system can have improved reliability and accuracy. For the redundant system the placement of redundant sensors is related to the system performance and also the number and proper orientation of sensors are important. We consider INS sensor configurations using two IMUs comprised mutually orthogonal sets of three. We suggest several configurations using two IMUs and analyze the system performance and the FDI(fault detection and isolation) properties from suggested configurations.

• 한국경영과학회지
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• 제23권1호
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• pp.97-107
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• 1998

This paper is concerned with a parallel system that sustains a time-independent load and consists of n components with exponential lifetimes. It is assumed that the total load is shared by the working components and the failures of components increase higher failure rates in the surviving components according to the relationship between the load and the fialure rates. The power rule model among several load-failure rate relationships is considered. We consider the system efficiency meausre as the expected profit earned by the system per unit time. The high load causes high gain but it also occurs frequent system failures. The expected profit per unit time is used as criterion to evaluate the system efficiency. The goal of system engineer is to determine the optimal load and redundant units maximizing the expected profit per unit time. First, the system reliability function is obtained and the optimization problem of the load-sharing parallel system is considered. Given the redundant units, the existence of the optimal load can be proved analytically and given the load, the optimal redundant units can be solved also analytically. The optimal load and redundant units are obtained simultaneously by numerical computation. Some numerical examples are studied.

• Journal of Mechanical Science and Technology
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• 제16권6호
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• pp.762-769
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• 2002

This paper presents how effective it is to use many features for improving the speed and accuracy of visual servo systems. Some rank conditions which relate the image Jacobian to the control performance are derived. The focus is to describe that the accuracy of the camera position control in the world coordinate system is increased by utilizing redundant features in this paper. It is also proven that the accuracy is improved by increasing the number of features involved. Effectiveness of the redundant features is evaluated by the smallest singular value of the image Jacobian which is closely related to the accuracy with respect to the world coordinate system. Usefulness of the redundant features is verified by the real time experiments on a Dual-Arm robot manipulator made by Samsung Electronic Co. Ltd..

• Transactions on Control, Automation and Systems Engineering
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• 제1권1호
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• pp.8-15
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• 1999

One of the main reason advocating redundant manipulators' superiority in application is that they can afford to optimize a dexterity measure, for example the manipulability measure. However, to obtain the gradient of the manipulability is not an easy task in case of general manipulator with high degrees of redundancy. This article proposes a method to compute the gradient of the manipulability, based on recursive algorithm to compute the Jacobian and its derivative using Denavit-Hartenberg parameters only. To characterize the null motion of redundant manipulators, the null space matrix using square minors of the Jacobian is also proposed. With these capabilities, the inverse kinematics of a redundant manipulator system can be done automatically. The result is easily extended to dual manipulator system using the relative kinematics.

• 한국산업정보학회논문지
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• 제20권4호
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• pp.75-87
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• 2015

중복시스템의 일반적인 구조는 기능을 수행하는 주요부품과 주요부품이 고장 나는 경우에 그 기능을 대신 수행하는 대기부품으로 구성되어 있다. 본 연구에서는 하나의 대기부품이 여러 개의 주요부품의 기능을 동시에 대신 수행할 수 있는 다기능 대기부품을 갖는 병렬시스템을 고려한다. 이 시스템을 구성하고 있는 모든 부품들은 작동상태와 고장상태만 갖는 반면 시스템은 구성 부품들의 상태에 따라 다중 상태를 갖는 것을 가정한다. 이러한 중복구조는 항공기와 같이 시스템의 중량이 중요한 요소인 시스템에서 많이 채택되고 있는 구조이다. 본 연구에서는 이와 같은 중복시스템의 신뢰도를 평가하기 위한 새로운 신뢰도모델링 기법을 제안하고 부품들이 상수고장률을 갖는 경우 마코프 분석 방법을 적용하여 시스템의 신뢰도를 구한다. 또한 본 연구에서 고려하고 있는 시스템과 기존에 이미 알려진 병렬시스템과 중복구조를 갖는 병렬시스템의 신뢰도를 비교하여 다기능 대기부품의 효과를 분석한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.267-270
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• 2000

In this paper, we consider the simple redundant structures with the function of hardware based active/standby control. The system includes two switch modules. The switch module is connected to a data bus, but only the active switch module has control of the data bus. The standby unit takes over the function of the active unit when the active unit failure or mode command are asserted. And this paper illustrate the high-speed router system and the overall redundant system architecture. The proposed redundant architecture for 80G Router system is verified and implemented with experiment.

• Journal of Power Electronics
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• 제11권4호
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• pp.533-541
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• 2011

The redundant operation of a parallel AC to DC converter via a serial communication bus is presented. The proposed system consists of three isolated CUK power factor correction modules. The controller for each converter is a dsPIC30F6010 microcontroller while a RS485 communication bus and the clock signal are used for synchronizing the data communication. The control strategy of the redundant operation relies on the communication of information among each of the modules, which communicate via a RS485 serial bus. This information is received from the communication checks of the converter module connected to the system to share the load current. Performance evaluations were conducted through experimentation on a three-module parallel-connected prototype, with a 578W load and a -48V dc output voltage. The proposed system has achieved the following: the current sharing is quite good, both the transient response and the steady state. The converter modules can perform the current sharing immediately, when a fault is found in another converter module. In addition, the transient response occurs in the system, and the output voltages are at their minimum overshoot and undershoot. Finally, the proposed system has a relatively simple implementation for the redundant operation.

• 한국국방경영분석학회지
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• 제5권2호
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• pp.73-80
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• 1979

In military applications of equipment, it is of the utmost importance that the equipment operates without breakdown for a specified length of time. We can increase the reliability of a system by adding redundant components to the basic nonredundant system. This study introduces a dynamic programming algorithm of finding optimum redundant design that maximizes the system reliability with constraints.