• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.26.6-26
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• 2001

In this paper we introduce a new algorithm that enables radial basis function network(RBFN) to be structured automatically and guarantees the stability of the RBFN. Because this new algorithm is efficient and also have the advantage of fast computational speed we adopt this algorithm as online learning scheme for uncertain nonlinear dynamical systems. Based on the fact that a 3-layered RBFN can represent a specific nonlinear function reasonably well by linearly combining a set of nonlinear and localized basis functions, we show that this RBFN can identify the nonlinear system very well without knowing the information of the system in advance.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1999년도 추계학술대회논문집
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• pp.371-374
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• 1999

This paper present the nonlinear control and the Lyapunov analysis of the nonlinear electro-hydraulic system for steering control of UCT. Electro-hydraulic system itself has the high nonlinearities arisen from the nonlinear characteristics of the pressure-fluid flow in valve and friction in cylinder. These nonlinearities are unmodeled terms in the transfer function. This paper presents the system modeling, analysis of stability based on the Lyapunov function and simulation of the nonlinear hydraulic servo system.

• 소음진동
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• 제10권3호
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• pp.451-456
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• 2000

In this paper a discrete time model for the identification of nonlinear vibration system with stick-slip friction is proposed. The proposed model can handle the highly nonlinear behavior of the friction such as stick-slip phenomenon and Stribeck effect. The basic idea of the proposed model is as follows : If the nonlinearity of the system can be predicted as a simple function then this nonlinear function term cab be directly used in the discrete time model. By doing this the number of nonlinear terms in the model can be much less than those of NARMAX model which is widely used nonlinear discrete model. The simulation result shows that the proposed model can estimate the response of the nonlinear vibration system with stick-slip friction very well with less computational effort.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.560-563
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• 1997

The conventional impedance control has been known to have the following problems: it has lack of specifying force directly and unknown environment stiffness has to be known priori in order to specify the reference trajectory. In this paper, new impedance force control that can control a desired force directly under unknown stiffness is proposed. A new nonlinear impedance function is developed based on estimation of unknown stiffness from force and position measurements. The nonlinear characteristics of the proposed impedance function are analyzed based on unknown environment position. Simulation studies with robot manipulator are carried out to test analytical results.

• 전기의세계
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• 제16권3호
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• pp.16-20
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• 1967

To analyze the stability creterion and the dynamic performance of the nonlinear reactor control system which involve the on-off element and gear backlash, the concept of discribing function is developed for the system of two nonlinear elements are connected by linear element. Using the derived discribing function and frequency responce method, the stability creterion and the dynamic performance of the nonlinear reactor control system are analyzed, and the results of the analysis are conformed by analog computor.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제8권2호
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• pp.15-21
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• 2004

A Conjugate Gradiant (CG) method is proposed for unconstained optimization which is invariant to a nonlinear scaling of a strictly convex quadratic function. The technique has the same properties as the classical CG-method when applied to a quadratic function. The algorithm derived here is based on a logarithmic model and is compared to the standard CG method of Fletcher and Reeves [3]. Numerical results are encouraging and indicate that nonlinear scaling is promising and deserves further investigation.

• 전자공학회논문지A
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• 제31A권8호
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• pp.1-6
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• 1994

In this paper, we introduce the nonlinear combiner structure which improves linear complexity and randomness properties on maximum length sequences generated by LFSR. Choosing the primitive polynomial over GF(2S04T) as feedback tap polynomial, we devise nonlinear combiner structure and analyze the random output sequences generated by LFSR with nonlinear function.

• 한국정보통신학회논문지
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• 제14권4호
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• pp.859-867
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• 2010

본 논문에서는 일반적인 비트기반의 비선형 결합함수를 고속화하기 위하여 워드기반 스트림 암호에서 적용될 워드기반 비선형 결합함수 구조를 제안하였다. 특히, 워드기반 병렬구조를 갖는 PS-WFSR을 제안하였고, 이를 활용하여 비트 기반 비선형 결합함수를 고속화시킨 4가지 형태의 워드기반 병렬형 비선형 결합함수를 다음과 같이 제안하였다. m-병렬 워드기반 비메모리 비선형 결합함수, m-병렬 워드기반 메모리 비선형 결합함수, m-병렬 워드기반 비선형 필터함수, m-병렬 워드기반 클럭조절형 함수를 제안하였고, 마지막으로 m-병렬 워드기반 DRAGON의 병렬 구조를 통하여 그 성능을 분석하였다.

• 제어로봇시스템학회논문지
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• 제15권4호
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• pp.413-419
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• 2009

A decentralized adaptive control method is proposed for large-scale systems with unknown time-delayed nonlinear interconnections unmatched in control inputs. It is assumed that the time-delayed interaction terms are bounded by unknown nonlinear bounding functions. The nonlinear bounding functions and uncertain nonlinear functions of large-scale systems are compensated by the function approximation technique using neural networks. The dynamic surface control method is extended to design the proposed memoryless local controller for each subsystem of uncertain nonlinear large-scale time delay systems. Therefore, although the interconnected systems consist of a large number of subsystems, the proposed controller can be designed simply. We prove that all the signals in the total closed-loop system are semiglobally uniformly bounded and the control errors converge to an adjustable neighborhood of the origin. Finally, an example is given to demonstrate the effectiveness and applicability of the proposed scheme.

• 융합신호처리학회논문지
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• 제2권4호
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• pp.77-84
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• 2001

신경망을 이용한 선형프로그랭 회로를 홉프필드가 제안한 이후로 이에 관한 많은 논문들이 발표되었으며, 그 중에는 비선형 프로그래밍 문제에 관한 것들도 많다. 그래서 비용함수가 비선형인 경우는 해결이 되었으나 제한조건이 비선형인 경우에는 해결되지 못한 상태이다. 이 논문에서는 제한조건이 비선형인 경우를 포함하는 즉 비용함수와 제한조건 모두 비선형인 경우를 풀 수 있는 일반적인 비선형프로그래밍 신경망을 제안하고자 한다.