Output-feedback Robust Tracking Control of Uncertain Systems via Adaptive Learning

Jun Zhao,Yongfeng Lv 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.4

This paper presents an adaptive learning method to achieve the output-feedback robust tracking control of systems with uncertain dynamics, which uses the techniques developed for optimal control. An augmented system is first constructed using the system state and desired output trajectory. Then, the robust tracking control problem is equivalent to the optimal tracking control problem with an appropriate cost function. To design the output-feedback optimal tracking control, an output tracking algebraic Riccati equation (OTARE) is then constructed, which can be used in the online learning process. To obtain the solution of the derived OTARE, an online adaptive learning method is proposed, where the input gain matrix is removed. In this learning algorithm, only the system output information is required and the observers widely used in the output-feedback optimal control design are removed. Simulations based on the power system are given to test the proposed method.

A Model-free Output Feedback Adaptive Optimal Fuzzy Controller for LC-filtered Three-phase Voltage Source Inverters

Nam Hai Trinh,Loc Ong Xuan,Nga Thi-Thuy Vu,Anh Tuan Nguyen 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.6

This paper proposes a model-free output feedback control-based adaptive fuzzy controller using a current-sensorless configuration for LC-filtered three-phase voltage source inverters (VSIs). The proposed adaptive fuzzy scheme is constructed of three parts: an adapter, an adaptive optimal fuzzy controller, and an adaptive optimal fuzzy identifier. The adapter is designed based on an adaptive neuro-fuzzy inference system (ANFIS) network which uses the error between the system output and identifier output as an input to generate the online updated parameters. Next, both the adaptive fuzzy controller and the fuzzy identifier are designed based on the Takagi-Sugeno (T-S) fuzzy model. In particular, the proposed algorithm is robust against external disturbance and parameter uncertainties due to not requiring the system parameters. Moreover, the proposed scheme uses a current-sensorless configuration, which reduces the system complexity and cost. Both the stability of the proposed method and the convergence of adapted parameters are completely assured by using the Lyapunov stability theory. Finally, the effectiveness of the proposed adaptive fuzzy controller is verified through simulation in comparison with a conventional T-S fuzzy controller. The results show that the proposed model-free output feedback control-based adaptive fuzzy controller yields better control performance, such as faster transient response, smaller steady-state error, and lower total harmonic distortion (THD) under the change of load (step changes of linear load, unbalanced load, and nonlinear load), parameter variations, and input disturbances.

Seismic test of modal control with direct output feedback for building structures

Lu, Lyan-Ywan Techno-Press 2001 Structural Engineering and Mechanics, An Int'l Jou Vol.12 No.6

In this paper, modal control with direct output feedback is formulated in a systematic manner for easy implementation. Its application to the seismic protection of structural systems is verified by a shaking table test, which involves a full-scale building model and an active bracing system as the control device. Two modal control cases, namely, one full-state feedback and one direct output feedback control were tested and compared. The experimental result shows that in mitigating the seismic response of building structures, modal control with direct output feedback can be as effective and efficient as that with full-state feedback control. For practical concerns, the control performance of the proposed method in the presence of sensor noise and stiffness modeling error was also investigated. The numerical result shows that although the control force may be increased, the maximum floor displacements of the controlled structure are very insensitive to sensor noise and modeling error.

투입 산출 환원기능에서 본 국회의 구성, 권한 및 의무

정극원(Jeong, Kuk-Won) 한국토지공법학회 2019 土地公法硏究 Vol.87 No.-

헌법은 국민주권주의와 민주주주의 원리에 의하여 국가권력의 정당성을 부여하여(투입), 국가권력은 권력분립주의에 따른 기능수행을 하며(산출), 법치국가원리에 의하여 그 산출은 다시 투입의 통제를 받도록 하여(환원) 국민주권주의와 국민의 권리보장이 이상적으로 실현되도록 하고 있다. 국민과 대표의 관계에서 주권의 투입만 있고 산출의 결과가 없다면 국가기능이 국민이 바라는 만큼 작동하지 않는 것이 되며, 주권의 투입에 의한 산출이 산출로서만 끝나고 더는 자동조절의 기능이 작동되지 못한다면 통제가 없는 국가권력의 행사가 되어 국가권력의 낭비가 초래된다. 국가권력에 대한 정치적인 투입(input)의 길을 상설화하고 있는 것 중에 하나가 선거제도이다. 국민의 대표기관인 국회는 유권자인 국민의선거라는 투입에 의하여 구성된다. 헌법 제41조에 제1항은 “국회는 국민의 보통 평등 직접 비밀선거에 의하여 선출된 국회의원으로 구성한다.”라고 규정하고 있다. 국민으로부터 선출된 국회는 그 기능을 수행하기 위하여 국회의장 부의장(헌법 제48조), 위원회 및 교섭단체 등의 조직을 둔다. 국회는 이러한 조직을 통하여 입법권, 재정에 관한 권한(조세법률주의와 예산심의권 결산심사권), 국정통제권(탄핵소추와 국정감사 조사권) 및 헌법기관구성권 등의 권한을 행사한다. 이러한 권한행사의 기능을 보다 더 잘 보장하기 위하여 국회의원에는 자율권(내부경찰권과 의원가택권)과 특권(불체포특권과 면책특권)을 가진다. 그 기능면에서 보면 이러한 것이 바로 산출(Output)이다. 산출에 대한 검토가 환원이다. 헌법은 국회의원에게 권한의 부여와 함께 의무도 규정하고 있다. 헌법상에 규정된 청렴의 의무, 국익우선의 의무, 이권개입의 금지 및 겸직금지가 바로 그것이다. 이러한 의무는 자신 들을 선출한 국민에 대한 Feedback이다. 문제는 헌법상의 이러한 의무가 도덕적 윤리적기능에 그친다는 점이다. 그런 점에서 본다면 국회에 있어서 Input과 Output은 있되, 사실상 Feedback은 없는 것이다. 이처럼 환원기능이 없다는 것은 헌법의 본질적 요소인 국민주권주의의 기능을 무력하가 하거나 약화시키게 하는 것이다. 국민으로부터 선출된 국회의 원에게는 더 높은 수준의 의무를 부과하고 있어야 한다. 국민의 대표기관인 국회의원의 행위는 국가기능의 실현뿐만 아니라 대국민 교육의 효과도 있기 때문이다. 한 나라의 국민의 수준이 그 대표의 수준을 정하기도 하지만, 그 대표의 행위가 국민의 품격을 높여 주는 것이다. 환원기능의 강화는 국회의 체질을 민주적으로 강화하게 될 뿐만 아니라 결국은 국민 의 권리향상과 복리증진은 물론 국익의 증진을 위하여 일하는 국회를 만들게 하는 것이다. 그리므로 헌법상에 규정된 국회의 의무를 법률을 통하여 보다 구체화하여야 하며, 도덕적 윤리적 의무를 넘어서 의원직의 상실로 까지 이어질 수 있도록 하는 강한 제도를 만드는것도 필요하다고 하겠다. 그러한 점에서 국민소환제의 도입도 필요한 것이다. 환원기능은 국회의원 개인에게 부여되는 의무이지만 결국은 주권자인 국민에 대한 책임을 강하게 담보하는 것이라는 점에서 그 중요성이 있다. Regarding the Constitution, by giving the legitimacy of the national power according to the principle of the citizens national sovereignty and the principle of the democracy, the national power performs (produces) the function according to the principle of power separation. And, according to the principle of the law-governed country, the output makes the control of the input received (the feedback) again. Thereby, it has been making the principle of the citizens national sovereignty and the guarantee of the rights of the citizens realized ideally. If, in the relationship between the citizens and the representative, there is only the input of the national sovereignty and no result of the output, it becomes the national function not operating to the extent of the desire by the citizens. And, if the output according to the input of the national sovereignty ends as the output only and if the function of the automatic adjustment cannot operate any longer, by being an exercise of the national power, which does not have a control, the waste of the national power is caused. One of the things that have been permanently establishing the road of the political input regarding the national power is the election system. The National Assembly, which is the representative organization of the citizens, gets organized according to the input of the election by the citizens, who are the voters. Clause 1, Article 41 of the Constitution has been regulating, The National Assembly shall be organized with the National Assemblymen who were elected through an ordinary, egalitarian, direct, and secret election by the citizens. For performing the function, the National Assembly, which had been elected by the citizens, shall have the organization with the Chairman of the National Assembly, the Vice-chairman (Article 48 of the Constitution), the committees, the negotiation bodies, etc. Through such an organization, the National Assembly exercises the rights, including the legislative right, the rights regarding the finance (The principle of no taxation without the law, the budget deliberation right, and the settlement evaluation right), the national affairs controlling right (The impeachment motion, the inspection of the government administration, and the investigation right), the right to organize the Constitutional organizations, etc. In order to guarantee the function of such an exercise of the right better, the National Assemblymen have the autonomy (The internal police authority and the right to prohibit the entry into the National Assembly and make one leave the National Assembly) and the special rights(The privilege of the freedom from arrest and the immunity). When seen from the functional aspect, such a thing is, indeed, the output. The examination regarding the output is the feedback. Together with the granting of the rights to the National Assemblymen, the Constitution has been regulating the duties, too. The obligation of the integrity, the duty of the prioritization of the national interests, the prohibition of the intervention in the rights, and the prohibition of holding more than one office, which are regulated in the Constitution are, indeed, them. Such duties are the feedbacks regarding the citizens who elected them. A problem is the point that such duties in the Constitution stop at the moral and ethical function. Seen from such a point, with regard to the National Assembly, there are the inputs and the outputs. Except, in fact, there are no feedbacks. The fact that there is no feedback function in this way makes the function of the principle of the citizens national sovereignty, which is an essential element of the Constitution, powerless or weakened. To the National Assemblymen, who were elected by the citizens, the duties on the higher levels must be imposed. This is because the actions by the National Assemblymen, who comprise the representative organization of the citizens, do not only materialize the natio

Feedback control strategies for active control of noise inside a 3-D vibro-acoustic cavity

Ashok K. Bagha,Subodh V. Modak 국제구조공학회 2017 Smart Structures and Systems, An International Jou Vol.20 No.3

This paper presents and compares three feedback control strategies for active control of noise inside a 3-D vibro-acoustic cavity. These are a) control strategy based on direct output feedback (DOFB) b) control strategy based on linear quadratic regulator (LQR) to reduce structural vibrations and c) LQR control strategy with a weighting scheme based on structural-acoustic coupling coefficients. The first two strategies are indirect control strategies in which noise reduction is achieved through active vibration control (AVC), termed as AVC-DOFB and AVC-LQR respectively. The third direct strategy is based on active structural-acoustic control (ASAC). This strategy is an LQR based optimal control strategy in which the coupling between the various structural and the acoustic modes is used to design the controller. The strategy is termed as ASAC-LQR. A numerical model of a 3-D rectangular box cavity with a flexible plate (glued with piezoelectric patches) and with other five surfaces treated rigid is developed using finite element (FE) method. A single pair of collocated piezoelectric patches is used for sensing the vibrations and applying control forces on the structure. A comparison of frequency response function (FRF) of structural nodal acceleration, acoustic nodal pressure, and piezoelectric actuation voltage is carried out. It is found that the AVC-DOFB control strategy gives equal importance to all the modes. The AVC-LQR control strategy tries to consume the control effort to damp all the structural modes. It is seen that the ASAC-LQR control strategy utilizes the control effort more intelligently by adding higher damping to those structural modes that matter more for reducing the interior noise.

불확실한 pure-feedback 비선형 계통에 대한 출력 궤환 적응 신경망 제어기

박장현(Jang-Hyun Park),김성환(Seong-Hwan Kim),장영학(Young-Hak Jang),유영재(Young-Jae Ryoo) 한국지능시스템학회 2013 한국지능시스템학회논문지 Vol.23 No.6

본 논문은 불확실한 연속시 단일입력 단일출력 pure-feedback 비선형 계통에 대해서 참고문헌 [15]에서 제안된 상태변수 궤환 적응 신경망 제어 알고리듬을 바탕으로 출력만이 측정 가능한 계통에 적용할 수 있는 출력 궤환 제어기를 제시한다. 고려하는 계통에 대한 출력 궤환 적응 신경망 제어기는 이 분야에서 아직까지 어느 문헌에서도 다루지 않은 주제이다. 제안된 출력 궤환 제어기는 백스테핑을 회피하여 상대적으로 간결한 제어 규칙과 단 하나의 신경망만이 사용된다는 [15]의 장점을 그대로 계승하며 적용되는 비선형 계통의 범주를 더 넓힌다는 의미를 가진다. Based on the state-feedback adaptive neuro-control algorithm for a SISO nonaffine pure-feedback nonlinear system proposed in [15], an output-feedback controller is proposed in this paper. The output-feedback adaptive neural-net controller for the considered nonlinear system has not been previously proposed in any other literatures yet. The proposed output-feedback controller inherits all the advantages of [15] such that it does not adopt backstepping and this results in relatively simple control and adapting laws. Only one neural network is required for the proposed adaptive controller. The proposed neural-net control scheme expands the applicable class of nonlinear systems.

Quantized Output Feedback Control of Networked Control Systems with Packet Dropout

Mei Yu,Shuang Bai,Ting Yang,Jianhua Zhang 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.5

This paper considers the quantized dynamic output feedback control of networked control system(NCS) with random packet dropout in both sensor-to-controller and controller-to-actuator channels. The packet losses in the two links are modeled as two independent Markov chains and the NCS is modeled as a Markov jump system. The stochastic switching signal for the quantized output feedback controller is designed to be a function of the number of successive packet loss in both of the two channels. Quantization density varies with the networked load condition. Then a sufficient condition of the stochastic stability with a prescribed H¥ performance level is established based on the Lyapunov-Krasovskii function approach. Furthermore, a quantized output feedback controller is obtained via the cone complement linearization method. Finally, simulation results are provided to verify the effectiveness of the proposed method.

Design of a variable structure output feedback control for uncertain dynamic systems

Yoo, Dong Sang 안성산업대학교 2002 論文集 Vol.34 No.-

Based on a Lyapunov function, we suggest a sufficient condition guaranteeing the robustness on the uncertainty and design a robust linear output feedback controller for a class of uncertain dynamic systems using eigenstructure assignment technique via output feedback. Also, we design a variable structure (VS) output feedback controller which is discontinuous on the predefined switching surface composed of only the measurable output, without changing the linear output feedback gain except its sign which is altered either negative or positive, if necessary. And we prove that the VS output feedback control makes the transient response be improved better than the linear output feedback control in the sense of Lyapunov.

Dynamic optimal output feedback control of satellite formation reconfiguration based on an LMI approach

Wei, Changzhu,Park, Sang-Young ELSEVIER PARIS 2017 AEROSPACE SCIENCE AND TECHNOLOGY Vol. No.

<P><B>Abstract</B></P> <P>This study presents a dynamic quadratic-optimal (DQO) output feedback controller for satellite formation reconfiguration based on a linear matrix inequality (LMI) approach. A relative motion model involving communication topology of formation flying on a circular reference orbit is established through graph theory. As the design of a static quadratic-optimal (SQO) output feedback controller was determined to be infeasible, emphasis is placed on designing a DQO output feedback controller. Introducing an impulse function enables us to transform the original DQO output feedback control (DQO-OFC) problem into an optimal L<SUB>2</SUB>-norm problem, which can be solved in the standard frame of an LMI approach. It is infeasible to employ a conventional substitution method to treat a nonlinear term with a quadratic form. Thus, an elimination method is adopted in order to address nonlinear terms in the matrix inequalities to obtain a set of equivalent LMIs. Additional control quantities are developed in order to retain the formation configuration in a non-zero state. Simulation results demonstrate validity and functionality of the proposed DQO output feedback controller.</P>

Adaptive Fuzzy Backstepping Dynamic Surface Control for Output-constrained Non-smooth Nonlinear Dynamic System

한성익,이장명 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.4

Output-constrained backstepping dynamic surface control (DSC) is proposed for the purpose of output constraint and precise output positioning of a strict feedback single-input, single-output dynamic system in the presence of deadzone and uncertainty. A symmetric barrier Lyapunov function (BLF) is employed to meet the output constraint requirement using DSC as an alternative method of backstepping control that is adopted mainly to deal with the BLF’s constraint control. However, using the ordinary DSC method with the BLF limits the selection of the control gain whereas this limitation does not exist in the backstepping structure. To remove this limitation, we propose a partial backstep-ping DSC method in which backstepping control is added only in the first recursive DSC design step. For precise positioning, an inverse deadzone method and adaptive fuzzy system are introduced to handle unknown deadzone and unmodeled nonlinear functions. We show that the semiglobal boundedness of the overall closed-loop signals is guaranteed, the tracking error converges within the prescribed region, and precise positioning performance is ensured. The proposed control scheme is experimentally evaluated using a robot manipulator.