Uniform robust exact differentiator based adaptive robust control for a class of nonlinear systems

2017 ◽  
Vol 40 (9) ◽  
pp. 2901-2911 ◽  
Author(s):  
Zhangbao Xu ◽  
Dawei Ma ◽  
Jianyong Yao

In this paper, an adaptive robust controller with uniform robust exact differentiator has been proposed for a class of nonlinear systems with structured and unstructured uncertainties. The adaptive robust controller is integrated with an uniform robust differentiator to handle the problem of the incalculable part of the derivative of virtual controls and the differential explosion happened in backstepping techniques. The stability of the closed loop system is demonstrated via Lyapunov method ensuring a prescribed transient and tracking performance. Simulation and experimental results are carried out to verify the advantages of the proposed method.

2014 ◽  
Vol 573 ◽  
pp. 328-333
Author(s):  
R. Ramya ◽  
K. Selvi ◽  
M. Tamilvanan

This paper deals with the design and evaluation of robust excitation controller for a single-machine infinite-bus power system. The design of the regulator guarantees the stability of the closed loop system and ensures the output voltage is maintained within an acceptable threshold. In addition, it damps out local mode oscillations for small signal disturbances. The designed robust controller is also analyzed under change in step input and disturbance, which limits the heavy oscillations on the speed ω and voltage. Glover-McFarlane loop shaping algorithm is applied in designing the robust excitation controller. Two different techniques such as Optimal control and mixed sensitivity approach is used in this paper. The performance of the AVR was analyzed and compared with IEEE type2 Exciter.


Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2783
Author(s):  
Yanbin Liu ◽  
Jue Wang ◽  
Luis Gomes ◽  
Weichao Sun

Backstepping method is a successful approach to deal with the systems in strict-feedback form. However, for networked control systems, the discontinuous virtual law caused by state quantization introduces huge challenges for its applicability. In this article, a quantized adaptive robust control approach in backsetpping framework is developed in this article for networked strict-feedback nonlinear systems with both state and input quantization. In order to prove the efficiency of the designed control scheme, a novel form of Lyapunov candidate function was constructed in the process of analyzing the stability, which is applicable for the systems with nondifferentiable virtual control law. In particular, the state and input quantizers can be in any form as long as they meet the sector-bound condition. The theoretic result shows that the tracking error is determined by the pregiven constants and quantization errors, which are also verified by the simulation results.


2019 ◽  
Vol 20 (8) ◽  
pp. 451-460 ◽  
Author(s):  
A. A. Kolesnikov ◽  
A. A. Kuz’menko

Sliding mode control (SMC) laws are commonly used in engineering to make a system robust to parameters change, external disturbances and control object unmodeled dynamics. State-of-the-art capabilities of the theory of adaptive and robust control, the theory of fuzzy systems, artificial neural networks, etc., which are combined with SMC, couldn’t resolve current issues of SMC design: vector design and stability analysis of a closed-loop system with SMC are involved with considerable complexity. Generally the classical problem of SMC design consists in solving subtasks for transit an object from an arbitrary initial position onto the sliding surface while providing conditions for existence of a sliding mode at any point of the sliding surface as well as ensuring stable movement to the desired state. As a general rule these subtasks are solved separately. This article presents a methodology for SMC design based on successive aggregation of invariant manifolds by the procedure of method of Analytical Design of Aggregated Regulators (ADAR) from the synergetic control theory. The methodology allows design of robust control laws and simultaneous solution of classical subtasks of SMC design for nonlinear objects. It also simplifies the procedure for closed-loop system stability analyze: the stability conditions are made up of stability criterions for ADAR method functional equations and the stability criterions for the final decomposed system which dimension is substantially less than dimension of the initial system. Despite our paper presents only the scalar SMC design procedure in details, the ideas are also valid for vector design procedure: the main difference is in the number of invariant manifolds introduced at the first and following stages of the design procedure. The methodology is illustrated with design procedure examples for nonlinear engineering systems demonstrating the achievement of control goals: hitting to target invariants, insensitivity to emerging parametric and external disturbances.


2011 ◽  
Vol 418-420 ◽  
pp. 185-191
Author(s):  
Li Jing Li ◽  
Bing Jun Li ◽  
Lan Bi ◽  
Xi Zhang ◽  
Chun Xi Zhang

This paper investigates an H∞ robust controller for improving the measurement accuracy of the Optical Voltage Transducer with noise and parameter uncertainty. Firstly, the optical voltage transducer based on closed-loop detection is analyzed, and the model of the system is established concerning noise and uncertainty. Secondly, according to the model, this paper is theoretically devoted to the study of the Robust control for meeting the design target, while guarantees that the closed-loop system is asymptotically stable. Furthermore, we give a design criterion in terms of linear matrix inequality for the Robust control in the presence of noise and uncertainty. Finally, the experimental results demonstrate the effectiveness and feasibility of the robust controller.


Author(s):  
Jinli Qu ◽  
Ronald N. Miles ◽  
N. Eva Wu

This paper presented an H∞-controller design to achieve active damping for a MEMS microphone system. The parametric uncertainties introduced by linearization process were modeled. The stability and performance of the closed-loop system were analyzed for the uncertain microphone model and both were shown to be robust. The nonlinear simulation further verifies that the controller offers the desired performance.


2008 ◽  
Vol 144 ◽  
pp. 16-21
Author(s):  
Arkadiusz Mystkowski ◽  
Zdzisław Gosiewski

Analysis of robustness of active magnetic bearing system is carried out in the paper. All of the most important acceptable levels of robustness are established. Rigid body model of a rotor is used for controller design, stability and analysis of robustness. Advanced tools for robust control are applied. The μ-synthesis is used to design a μ robust controller to stabilize the shaft that is supported magnetically. The influence of robust control on the sensitivity of plant with an uncertainty dynamics is shown. The influence of dynamic uncertainty on the robustness level of closed-loop system is considered. Small gain theorem and robustness theorem for an active magnetic bearing are investigated. Finally, the experimental results confirm the analytical investigations of the robust control of vibrations.


2015 ◽  
Vol 2015 ◽  
pp. 1-14
Author(s):  
Chuanjing Hou ◽  
Lisheng Hu ◽  
Yingwei Zhang

An adaptive failure compensation scheme using output feedback is proposed for a class of nonlinear systems with nonlinearities depending on the unmeasured states of systems. Adaptive high-gain K-filters are presented to suppress the nonlinearities while the proposed backstepping adaptive high-gain controller guarantees the stability of the closed-loop system and small tracking errors. Simulation results verify that the adaptive failure compensation scheme is effective.


2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Xiaohua Liu ◽  
Wuquan Li

This paper investigates the stability of a class of stochastic nonlinear systems with Markovian switching via output-feedback. Based on the backstepping design method and homogeneous domination technique, an output-feedback controller is constructed to guarantee that the closed-loop system has a unique solution and is almost surely asymptotically stable. The efficiency of the output-feedback controller is demonstrated by a simulation example.


Author(s):  
Beibei Ren ◽  
Qing-Chang Zhong

In this paper, the UDE (uncertainty and disturbance estimator) based robust control is investigated for a class of non-affine nonlinear systems in a normal form. Control system design for non-affine nonlinear systems is one of the most difficult problems due to the lack of mathematical tools. This is also true even for the exact known non-affine systems because of the difficulty in explicitly constructing the control law. It is shown that the proposed UDE-based robust control strategy leads to a stable system. The most important features of the approach are that (i) by adding and subtracting the control term u, the original non-affine form is transformed into a semi-affine form, which not only simplifies the control design procedure, but also avoids the singularity problem of the controller; (ii) the employment of UDE makes the estimation of the lumped uncertain term which is a function of control input, states and disturbances possible, rather than states alone; and (iii) it does not require any knowledge (e.g., bounds) about the uncertainties and disturbances, except the information about the bandwidth, during the design process. The stability of the closed-loop system is established. Effectiveness of the proposed approach is demonstrated through application to the hard disk driver control problem.


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