• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1496-1499
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• 1996

A nonlinear tracking control technique developed for the control of nonlinear systems has been applied to the autopilot design of missile system. The difficulties in the application of inversion based control methods such as input-output feedback linearization and sliding mode control due to nonminimum phase characteristics are discussed. To avoid the stability problem associated with unstable zero dynamics, the input-output feedback linearization is applied with output-redefinition method to normal acceleration control. The output-redefinition method gives an indirect way to apply the nonlinear controls to nonminimum phase plants by redefining the plant output such that the tracking control of the modified output ensures the asymptotic tracking of the original output. The numerical simulation shows satisfactory results both for nominal and for slightly perturbed missile systems adopting the sliding mode control technique. However, the robustness problem in this method is briefly investigated and verified with the simulation.

• 한국산업융합학회 논문집
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• 제25권2_1호
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• pp.161-168
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• 2022

This study proposed a new approach to impliment a robusut control of comsumer-friendly flexible manipulator with five joint for untact working in filed work-site. The output redefinition approach was used to overcome the non minimum phase characteristic of the system. The new output is defined so that the zero dynamics related to this output are stable. The control strategy is based on an computed torque method which is applicable to a class of time-invariamt phase linear systems whose uncertainties appear in output loop stable. The controller is composed of a stabilizing joint controller and an output redefinition tracking controller. Experimental results are also presented to verify the effectiveness of the proposed control scheme.

• 제어로봇시스템학회논문지
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• 제16권4호
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• pp.329-334
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• 2010

This paper presents the design of a neural network based adaptive control for missile. Acceleration of missile by tail fin control cannot be controllable by DMI (Dynamic Model Inversion) directly because it is non-minimum phase system. To avoid the non-minimum phase system, dynamic model inversion is applied with output-redefinition method. In order to evaluate performance of the suggested controllers we selected the three cases such as control surface fail, control surface loss and wing loss for model uncertainty. The corresponding aerodynamic databases to the failure cases were calculated by using the Missile DATACOM. Using a high fidelity 6DOF simulation program of the missile the performance was evaluates.

• International Journal of Control, Automation, and Systems
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• 제4권3호
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• pp.308-317
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• 2006

To control the tip position of a flexible-link manipulator, a neural network (NN) controller is proposed in this paper. The dynamics error used to construct NN controller is derived based on output redefinition approach. Without the filtered tracking error, the proposed NN controller can still guarantee the closed-loop system uniformly asymptotically stable as well as NN weights bounded. Furthermore, the tracking error of desired trajectory can converge to zero with the proposed controller. For comparison an NN controller with filtered tracking error is also designed for the flexible-link manipulator. Finally, simulation studies are carried out to verify the theoretic results.

• Spatial Information Research
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• 제14권3호
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• pp.299-319
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• 2006

본 연구는 위성 영상을 이용한 녹지 조사의 결과를 지도화하고 다양한 시기의 녹지변화 실태를 통합한 데이터베이스를 구축하여 그 결과를 토대로 GIS의 공간 객체 재정의 기법을 이용하여 녹지의 총량규제를 위한 기초자료를 확보할 수 있는 지의 가능성을 탐색하고자 출발하였다. 그리하여 사례 연구지역의 녹지 변화 추세에 대한 평가가 이루어졌고 규제 총량을 산정하는 과정에서 활용 방안이 제시되었다. 아울러 공간 객체 재정의를 통한 총량 규제 기초자료를 확보하는 데 있어 고려해야 할 기술적인 문제들과 더불어 실무에 도입시 고려하여야 할 핵심 사안(토지 모자이크의 분류, 녹피을 훼손 추세의 평가 등)에 대한 지침을 제시하였다. 기존에 조사지점에만 국한된 통계 수치정보가 광역적인 녹지 공간 변화 추이를 시각적으로 제시하는 데 많은 한계가 있었으나 공간 객체 재정의 기법의 활용을 통해 녹지의 규제 총량 결정과정의 설득력 확보에 기여할 수 있을 것으로 판단되었다. 본 연구가 녹지 보전에 있어 객관적인 데이터에 의거한 정책결정이 아닌 직관에 의존하여 왔던 관행을 개선될 수 있는 계기가 되어 향후 녹지보전관련 기술적인 측면이나 정책적인 측면에서 중요한 참고 자료가 될 수 있을 것으로 사료된다.

• International Journal of Aeronautical and Space Sciences
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• 제12권1호
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• pp.78-83
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• 2011

Traditional autopilot design requires an accurate aerodynamic model and relies on a gain schedule to account for system nonlinearities. This paper presents the control architecture applied to a dynamic model inversion at a single flight condition with an on-line neural network (NN) in order to regulate errors caused by approximate inversion. This eliminates the need for an extensive design process and accurate aerodynamic data. The simulation results using a developed full nonlinear 6 degree of freedom model are presented. This paper also presents the stability evaluation for control systems to which NNs were applied. Although feedback can accommodate uncertainty to meet system performance specifications, uncertainty can also affect the stability of the control system. The importance of robustness has long been recognized and stability margins were developed to quantify it. However, the traditional stability margin techniques based on linear control theory can not be applied to control systems upon which a representative non-linear control method, such as NNs, has been applied. This paper presents an alternative stability margin technique for NNs applied to control systems based on the system responses to an inserted gain multiplier or time delay element.

• 한국멀티미디어학회논문지
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• 제1권2호
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• pp.224-238
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• 1998

확장된 마크흐름선도(EMFG: Extended Mark Flow Graph)는 이산 시스템을 개념적으로 또는 상세하게 설계할 수 있는 강력한 도구 일 뿐만 아니라 시스템을 직접적으로 구현하기 위한 적당한 표현이다. 그러나 EMFG의 다소 복잡한 표현으로 인해 수학적인 해석이 불가능하여 시스템의 설계나 해석에 어려움이 있다. 따라서 본 연구에서는 수학적인 해석이 가능하도록 EMFG의 표현을 재정의하였고, 표현 불가능한 부분이 가능하도록 트랜지션에 출력 역 아크를 도입하였다. 또한 EMFG의 회로변환에서 잘못 변환되는 부분들을 해결하였으며, 수식을 사용한 회로변환 방법을 제안하였다. 마지막으로 기존의 EMFG와 재정의된 EMFG를 비교하였고, 재정의된 EMFG로써 0101 감지기 회로를 설계하고 대응하는 회로로 변환하였다.