서지주요정보
쌍행렬 공진화 알고리듬을 이용한 강인 제어기 설계 = Robust control design using bimatrix co-evolution algorithm
서명 / 저자 쌍행렬 공진화 알고리듬을 이용한 강인 제어기 설계 = Robust control design using bimatrix co-evolution algorithm / 허종.
저자명 허종 ; Hur, Jong
발행사항 [대전 : 한국과학기술원, 2004].
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8015463

소장위치/청구기호

학술문화관(문화관) 보존서고

DAE 04002

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#### 초록정보

A bimatrix co-evolution algorithm is proposed to solve the parameter robust control problem subject to design requirements. The parameter robust control problem is to design the controller having the robust performance against the worst, or the most performance degrading, uncertainties. This is often expressed as a game between the controller and uncertain parameters and the game is formulated as a minimax problem whose solution is known as a saddle-point solution. It is difficult to obtain the saddle-point solution by using conventional methods but if the solution is once secured, the resulting controller made from the solution always guarantees the robustness against bounded parameter uncertainties. In addition, when there are various kinds of design requirements such as parameter limits or condition functions, it is expressed as a constrained minimax problem, which is extremely hard to be solved using existing optimization methods. In this dissertation, a bimatrix co-evolution algorithm is proposed as a new approach addressing the constrained minimax problem by combining a bimatrix game concept and the co-evolution algorithm. In this approach, each of two players, the controller and the uncertain parameters, has an independent fitness measure which is composed of a performance term and a penalty term derived from the constraints. Because the constraints should be satisfied by the robust solution or the optimized parameters, both of the players cooperate to minimize the penalty terms while they fight for the performance trade-off. These two contrary actions of two players are conducted simultaneously in the bimatrix game, in which each of two players has a fitness measure matrix calculated by its population. In general, the robust solution can not be obtained at the first bimatrix game. The proposed algorithm finds the robust solution by using the parallel evolutions of two populations. Each of two evolving populations has an independent evolution process except the fitness measure process where the bimatrix game is conducted. Then, two populations converge to the robust solution through successive bimatrix games. In the proposed algorithm, the cooperative Stackelberg game method is adopted, in which the optimizing parameter is the leader who determines its strategy first and the uncertainty is the follower who reacts to the leader`s decision. Moreover, due to the prematuring nature of Evolution Algorithms, the proposed. algorithm may not converge to the solution which satisfies the given constraints for every possible uncertainty deviation. To exclude this possibility, some random populations of the uncertainty are generated and distributed over the given uncertainty range at every generation. These secondary populations are quite effective to find the robust solution satisfying all constraints. This is verified by solving a simple constrained minimax problem. The proposed algorithm is applied to the robust control design benchmark problem. The benchmark plant is a two-mass-spring system with noncollocated sensor and actuator. The performance of the proposed algorithm is compared with 10 solutions based on analytic approaches such as $H_∞$, nonlinear constrained optimization, and so on. The bimatrix coevolution algorithm results a satisfactory robustness of performance and stability. In order to show more practical application, the proposed algorithm is applied to the robust attitude control design of a flexible launch vehicle with design constraints, which is a representative parameter robust control problem as the structural elasticity makes the vehicle easily unstable by small change of parameters. The equations of motion in pitch plane are derived and a linearized state equation containing 3rd-order bending mode is formulated. A lower-order classical type controller composed of PID and notch filter is used and optimized by using the proposed algorithm. The numerical results show that it can find the robust controller and handle design requirements without difficulty.

#### 서지기타정보

청구기호 {DAE 04002 x, 122 p. : 삽도 ; 26 cm 한국어 부록 : 제A장, 안장점 조건의 증명. - 제B장, 진화 전략. - 제C장, Benchmark 문제에 대한 제어기. - 제D장, 유연구조 발사체의 선형화된 상태방정식 저자명의 영문표기 : Jong Hur 지도교수의 한글표기 : 탁민제 지도교수의 영문표기 : Min-Jea Tahk 수록잡지명 : "Parameter robust control design using bimatrix co-evolution algorithms". Engineering optimization, v.35 no.4, pp.417-426(2003 Aug.) 학위논문(박사) - 한국과학기술원 : 항공우주공학전공, 참고문헌 : p. 113-122 강인제어 파라미터 불확실성 쌍행렬 게임 공진화 알고리듬 구속조건이 있는 최소최대문제 ROBUST CONTROL PARAMETER UNCERTAINTY BIMATRIX GAME CO-EVOLUTION ALGORITHM CONSTRAINED MINIMAX PROBLEM
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