• Transactions on Control, Automation and Systems Engineering
• /
• 제4권4호
• /
• pp.264-269
• /
• 2002

In this paper, Η$_{\infty}$ depth and course controller of an AUV(Autonomous Underwater Vehicle) using Η$_{\infty}$ servo control is proposed. The Η$_{\infty}$ servo problem is formulated to design the controllers satisfying a robust tracking property with modeling errors and disturbances. The solution of the Η$_{\infty}$ servo problem is as fellows: first, this problem is modified as an Η$_{\infty}$ control problem for the generalized plant that includes a reference input mode, and then a sub-optimal solution that satisfies a given performance criteria is calculated by LMI(Linear Matrix Inequality) approach. The Η$_{\infty}$ depth and course controller are designed to satisfy with the robust stability about the modeling error generated from the perturbation of the hydrodynamic coefficients and the robust tracking property under disturbances(wave force, wave moment, tide). The performances of the designed controllers are evaluated with computer simulations, and finally these simulation results show the usefulness and application of the proposed Η$_{\infty}$ depth and course control system.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
• /
• pp.215-215
• /
• 2000

In this paper, depth and course controllers of autonomous underwater vehicles using H$_{\infty}$ servo control are proposed. An H$_{\infty}$ servo problem is formulated to design the controllers satisfying a robust tracking property with modeling errors and disturbances. The solution of the H$_{\infty}$ servo problem is as follows: first, this problem is modified as an H$_{\infty}$ control problem for the generalized plant that includes a reference input mode, and then a sub-optimal solution that satisfies a given performance criteria is calculated by LMI(Linear Matrix Inequality) approach. The H$_{\infty}$ depth and course controllers ate designed to satisfy with the robust stability about the modeling error generated from the perturbation of the hydrodynamic coefficients and the robust tracking property under disturbances(wave force, wave moment, tide). The performances(the robustness to the uncertainties, depth and course tracking properties) of the designed controllers are evaluated with computer simulations, and finally these simulation results show the usefulness and application of the proposed H$_{\infty}$ depth and course control systems.

• 대한기계학회논문집A
• /
• 제27권8호
• /
• pp.1353-1362
• /
• 2003

This paper considers a simultaneous optimization problem of structure and control systems. The problem is generally formulated as a non-convex optimization problem for the design parameters of mechanical structure and controller. Therefore, it is not easy to obtain the global solutions for practical problems. In this paper, we parameterize all design parameters of the mechanical structure such that the parameters work in the control system as decentralized static output feedback gains. Using this parameterization, we have formulated a simultaneous optimization problem in which the design specification is defined by the Η$_2$and Η$\_$$\infty$/ norms of the closed loop transfer function. So as to lead to a convex problem we approximate the nonlinear terms of design parameters to the linear terms. Then, we propose a convex optimization method that is based on linear matrix inequality (LMI). Using this method, we can surely obtain suboptimal solution for the design specification. A numerical example is given to illustrate the effectiveness of the proposed method.

• 한국지능시스템학회논문지
• /
• 제7권3호
• /
• pp.72-80
• /
• 1997

A new design method for Takagi-Sugeno (T-S in short) fuzzy controller which guarantees global asymptotic stability and satisfies a desired performance is proposed in this paper. The method uses LMI(Linear Matrix Inequality) approach to find the common symmetric positive definite matrix P and feedback fains K/sub i/, i= 1, 2,..., r, numerically. The LMIs for stability criterion which treats P and K'/sub i/s as matrix variables is derived from Wang et al.'s stability criterion. Wang et al.'s stability criterion is nonlinear MIs since P and K'/sub i/s are coupled together. The desired performance is represented as $ LMIs which place the closed-loop poles of $ local subsystems within the desired region in s-plane. By solving the stability LMIs and pole placement constraint LMIs simultaneously, the feedback gains K'/sub i/s which gurarntee global asymptotic stability and satisfy the desired performance are determined. The design method is verified by designing a T-S fuzzy controller for an inverted pendulum with a cart using the proposed method.

• 한국지능시스템학회논문지
• /
• 제21권5호
• /
• pp.630-636
• /
• 2011

본 논문은 매개변수 불확실성을 가지는 Takagi-Sugeno(T-S) 퍼지 시스템의 안정도 해석과 안정화 조건을 고려한다. T-S 퍼지 시스템의 안정도 해석 시 conservativeness를 줄이기 위해 퍼지 리아푸노프 함수를 이용한다. 매개변수 불확실성을 가지고 있는 시스템의 안정도를 해석하고 시스템을 안정화 시키는 퍼지 강인 제어기 설계 기법을 제시한다. 안정도조건과 안정화조건은 선형행렬부등식의 형태로 표현된다. 모의실험을 통해 제안된 접근 방법의 효용성을 보인다.

• 한국해양공학회지
• /
• 제14권4호
• /
• pp.35-42
• /
• 2000

The sway control problem of the pendulum motion of a container hanging on the trolly, which transports containers from a container ship to trucks, is considered in the paper. In the container crane control problem, suppressing the residual swing motion of the container at the end of acceleration or the case of that the unexpected disturbance input exists is main issue. For this problem, in general, the trolley motion control strategy is introduced and applied. But in this paper, we introduce and synthesize a new type of swing motion control system. In this control system, a small auxiliary mass is installed on the spreader. And the actuator reacts against the auxiliary mass, applying intertial control forces to the container to reduce the swing motion in the desired manner. In this paper, we apply the LMI approach and simultaneous optimization design method to design the anti-swing motion control system for the controlled plant. And the simulation result shows that the proposed control strategy is shown to be robust to disturbances like winds and initial sway motion.

• International Journal of Control, Automation, and Systems
• /
• 제6권1호
• /
• pp.24-34
• /
• 2008

A novel neural network model, termed the standard neural network model (SNNM), similar to the nominal model in linear robust control theory, is suggested to facilitate the synthesis of controllers for delayed (or non-delayed) nonlinear systems composed of neural networks. The model is composed of a linear dynamic system and a bounded static delayed (or non-delayed) nonlinear operator. Based on the global asymptotic stability analysis of SNNMs, Static state-feedback controller and dynamic output feedback controller are designed for the SNNMs to stabilize the closed-loop systems, respectively. The control design equations are shown to be a set of linear matrix inequalities (LMIs) which can be easily solved by various convex optimization algorithms to determine the control signals. Most neural-network-based nonlinear systems with time delays or without time delays can be transformed into the SNNMs for controller synthesis in a unified way. Two application examples are given where the SNNMs are employed to synthesize the feedback stabilizing controllers for an SISO nonlinear system modeled by the neural network, and for a chaotic neural network, respectively. Through these examples, it is demonstrated that the SNNM not only makes controller synthesis of neural-network-based systems much easier, but also provides a new approach to the synthesis of the controllers for the other type of nonlinear systems.

• 한국지능시스템학회논문지
• /
• 제17권4호
• /
• pp.483-487
• /
• 2007

본 논문은 시변 시간 지연을 가지는 선형 뉴트럴 시스템에 관한 관측기 설계 및 안정도 해석에 관해서 논의한다. 시변 시간 지연을 가지는 선형 뉴트럴 시스템의 안정도를 판별하기 위하여 Lyapunov-Krasovskii의 이론을 도입한다. 오차 상태 방정식의 안정도 조건으로 시간 변동 시간 지연에 종속적인 충분조건을 제시한다. 선형 행렬 부등식의 해를 이용하여 관측기의 이득 값을 설계하며, 설계된 관측기를 이용하여 오차 상태 방정식의 안정도를 판별한다. 본 논문의 결과는 Luenberger가 제안했던 관측기의 일반적인 결과를 나타냄을 확인한다. 모의실험을 통해 제안된 이론을 입증한다.

• 한국지능시스템학회논문지
• /
• 제8권5호
• /
• pp.51-60
• /
• 1998

퍼지 시스템의 안정도와 퍼지 제어기의 설계 방법론에 관한 연구는 최근 들어 많은 주목을 받아왔다. 본 논문은 TS(Takagi-Sugeno) 퍼지 모델로 표현된 비선형 시스템에 대한 제어기 설계분제가 선형행렬부등식(LMI, linear matrix inequality)을 포함하는 convex 문제로 간략화됨을 보인다. 입력행렬의 구조에 따라서 TS 퍼지 시스템을 세 가지로 분류하고, 각각에 대해 선형행렬부등식을 이용한 제어기 설계 방법을 제시한다. 또한 안정도 이외의 성능용건을 고려한 제어기를 설계한다. 제안된 설계 방법론을 설명하기 위해 예제를 다룬다.

• Environmental Engineering Research
• /
• 제24권1호
• /
• pp.144-149
• /
• 2019

Landfill leachate constitutes one of the most polluting wastewaters. Their treatment was considered difficult due to the presence of high concentration of organic matter, ammonia, toxic organic compounds and heavy metals. Biological processes were found to be effective in several cases, but they are limited by the presence of inhibitory compounds in leachate. In this study we develop a biological process for the leachate biodetoxification using Trametes trogii (T. trogii; CLBE55). Results show that laccase activity, mycelia growth and chemical oxygen demand (COD) removal efficiencies varied depending on the leachate and ammonium concentration. Indeed T. trogii was able to grow in the presence of low concentration of landfill leachate of 10 and 30%. In fact, the biomass produced was 4.7 and 3.7 g/L, respectively leading to a COD removal of 66 and 53%, respectively. However, when the concentration of the introduced leachate exceeds 30%, the treatment efficiency and particularly the COD removal decreases to reach 15% at 100% leachate. The effect of the ammonia was also studied and results showed that the addition of 5 g/L of ammonia inhibited totally the production of laccase and the COD removal.