불확실성을 가지는 비선형 시스템에 적용을 위한 강인 외란 추정 기반 제어 설계 방법
Design of Robust Disturbance Observer-Based Control Methods with Applications to Uncertain Nonlinear Systems
- 주제(키워드) 시스템 불확실성 , 펜듀봇 시스템 , 외란 추정 기반 제어 , LuGre 마찰력 추정기 , 강 인 외란 추정기 , 원자력 연구로 , 외란 추정 기반 궤환 선형화 제어 , 퍼지 기반 제한 기법 , 외란 추정 기반 규정 성능 제어
- 발행기관 아주대학교
- 지도교수 좌동경
- 발행년도 2016
- 학위수여년월 2016. 2
- 학위명 박사
- 학과 및 전공 일반대학원 전자공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000021574
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Practical control systems are always a ected by system uncertainty which includes the friction force, parameter uncertainty, unmodeled dynamics, measurement noise, external disturbance, etc. These system uncertainties can degrade the control performance. Although much research has been conducted on the control considering the system uncertainty in the nonlinear mechanical systems, the disturbance observer-based control methods have been studied much rather recently. Recent study shows that the disturbance observer-based control for uncertain nonlinear systems to improve the control performance is still one of the major open problems. With this in mind, the focus of this dissertation is to develop a robust disturbance observer-based control strategy for the uncertain nonlinear systems including pendubot and nuclear research reactor system to achieve the satisfactory control performance. First, the friction force in the pendubot system has been formally introduced by both LuGre and dynamic friction models, which can cause the limit-cycle phenomenon around the unstable equilibrium point. In addition, the dynamic friction model in the pendubot system is verfi ed through the simulation and experimental results. Here, we decompose a pendubot system into actuated and unactuated subsystem to compensate for the overall uncertainties at the same time. Then, we design the LuGre friction observer and the robust disturbance observer which ensure exactly compensation of its uncertainties in the pendubot system. We provide a comparison study which shows that the proposed control method provides more robust and effectiveness than previous swing-up and balancing control method in the presence of the system uncertainties. Second, a robust disturbance observer-based feedback linearization control (FLC) method combining an PI-like control law for uncertain research reactor system with the unmeasurable thermal feedback eff ect is proposed. In addition, the input as actual motor can be obtained by the inverse power control system model in the practical point of view. Particularly, a fuzzy-based limiting method has been developed to constrain the power change rate within the critical value for safety reason, which makes it easy to be applied to the heavy industrial reactor system. Accordingly, we show that the proposed control method can guarantee the asymptotic stability as well as the improved control performance even in the presence of system uncertainties, unlike the conventional reactor control method. Finally, a disturbance observer-based prescribed performance control (PPC) law to deal with both system uncertainty and control performance is proposed, where PPC method is utilized to improve its performance such as transient response, steady-sate error, maximum overshoot, and convergence rate. Thus, the proposed approach is more e ffective and can obtain the more satisfactory control performance compared with previous FLC. Therefore, the control performance can be signifi cantly improved by compensating for the system uncertainty. Each result is supported through rigorous Lyapunov-based stability proofs, numerical simulations, and/or experimental demonstrations.
more목차
1 Introduction 1
1.1 Background and Motivation 1
1.1.1 Robust DOB-Based Swing-Up and Balancing Control for a Pendubot 1
1.1.2 Robust DOB-Based Feedback Linearization Control for a Nuclear Research Reactor 5
1.1.3 Robust DOB-Based Prescribed Performance Control for a Nuclear Research Reactor 8
1.2 Contributions of the Dissertation 10
1.3 Outline of the Dissertation 14
2 Robust Disturbance Observer-Based Control Method for Pendubot System with Dynamic Friction 15
2.1 Introduction 15
2.2 Pendubot System 16
2.2.1 Pendubot Dynamics 16
2.2.2 Equilibrium Con figuration 19
2.3 Friction Model 20
2.3.1 LuGre Fiction Model 20
2.3.2 Dynamic Friction Model 21
2.4 Robust Disturbance Observer-Based Swing-Up and Balancing Control 23
2.4.1 Robust Swing-Up Control 23
2.4.2 LuGre Model-Based Friction Observer 27
2.4.3 Robust Disturbance Observer 31
2.4.4 Robust Balancing Control 35
2.5 Numerical Simulations 39
2.5.1 Verifi cation of the Friction Model 39
2.5.2 Evaluation of the Pendubot Control System Performance 42
2.6 Experimental Results 48
2.7 Conclusion 58
3 Robust Disturbance Observer-Based Feedback Linearization Control for Nuclear Research Reactor with System Uncertainties 60
3.1 Introduction 60
3.2 Nuclear Research Reactor 61
3.2.1 Nuclear Research Reactor System 62
3.2.2 Nonlinear Reactor Model 62
3.2.3 Reactivity Feedback 67
3.3 Robust Disturbance Observer-Based Feedback Linearization Control for Power Control System 69
3.3.1 Feedback Linearization Control with PI-like Compensation 69
3.3.2 Robust Disturbance Observer 72
3.4 Fuzzy-Based Power Change Rate Limiting Method for Power Control System 74
3.4.1 Structure of Power Control System 74
3.4.2 Design of Motor Step in Control Rod using Inverse Power Control System Model 75
3.4.3 Design of Motor Step in Control Rod using Fuzzy-Based Power Change Rate Limiting Method 78
3.5 Numerical Simulations 81
3.6 Conclusion 90
4 Robust Disturbance Observer-Based Prescribed Performance Control for Nuclear Research Reactor with System Uncertainties 91
4.1 Introduction 91
4.2 Preliminary of Prescribed Performance Function 92
4.2.1 Performance Function 92
4.2.2 Error Transformation 95
4.3 Prescribed Performance Control 97
4.4 Numerical Simulations 100
4.5 Conclusion 101
5 Conclusions and Future Research 104
5.1 Conclusions 104
5.2 Directions for Future Research 107
A Robust Disturbance Observer Analysis 109
A.1 Proof of Theorem 2.3 109
Bibliography 111
Abstract in Korea 118
