Two-degree-of-freedom compensator design for disturbance attenuation problem via higher order sinusoidal input describing functions theory

2019 ◽  
pp. 014233121988037
Author(s):  
Bilal Erol ◽  
Muhammed Ali Oz ◽  
Levent Ucun
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
Higher Order ◽  
Loop System ◽  
Disturbance Attenuation ◽  
Closed Loop System ◽  
Describing Functions ◽  
Sinusoidal Input ◽  
Bounded Uncertainties ◽  
Norm Bounded Uncertainties

In order to deal with disturbance attenuation problem in the presence of norm bounded uncertainties, different techniques involving [Formula: see text]/[Formula: see text] and linear quadratic regulator (LQR) designs exist in literature. The major drawbacks of these approaches may be classified as obtaining controllers with high order terms and too much computational load during the controller design. Hence, two-degree-of freedeom (2-DOF) controller design is taken into consideration in this study in order to avoid some of these drawbacks in the controller design and implementation process for disturbance attenuation problem. Here, the procedure for the design of 2-DOF structure is divided into two parts: designing [Formula: see text] controller to stabilize the closed loop system and implementing a higher order sinusoidal input describing functions (HOSIDF)-based compensator as a secondary controller in order to increase the disturbance attenuation performance of the overall closed loop system where the norm bounded uncertainties already exist. Thanks to the Lur’e type system definition that is also used in the design process of HOSIDF compensator, the research also proves that the proposed 2-DOF design structure is suitable to be implemented into the systems involving nonlinearities such as actuator saturation.

scholarly journals Robust H∞ Loop Shaping Controller Synthesis for SISO Systems by Complex Modular Functions

2021 ◽  
Vol 26 (1) ◽  
pp. 21
Author(s):  
Ahmad Taher Azar ◽  
Fernando E. Serrano ◽  
Nashwa Ahmad Kamal
Keyword(s):  
Design Methodology ◽  
Closed Loop ◽  
Complex Analysis ◽  
Controller Design ◽  
Filter Design ◽  
Design Procedure ◽  
Elliptic Functions ◽  
Loop System ◽  
Closed Loop System ◽  
Loop Shaping

In this paper, a loop shaping controller design methodology for single input and a single output (SISO) system is proposed. The theoretical background for this approach is based on complex elliptic functions which allow a flexible design of a SISO controller considering that elliptic functions have a double periodicity. The gain and phase margins of the closed-loop system can be selected appropriately with this new loop shaping design procedure. The loop shaping design methodology consists of implementing suitable filters to obtain a desired frequency response of the closed-loop system by selecting appropriate poles and zeros by the Abel theorem that are fundamental in the theory of the elliptic functions. The elliptic function properties are implemented to facilitate the loop shaping controller design along with their fundamental background and contributions from the complex analysis that are very useful in the automatic control field. Finally, apart from the filter design, a PID controller loop shaping synthesis is proposed implementing a similar design procedure as the first part of this study.

scholarly journals Vibration-Attenuation Controller Design for Uncertain Mechanical Systems with Input Time Delay

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Yuanchun Ding ◽  
Falu Weng ◽  
Xiaohua Jiang ◽  
Minkang Tang
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
State Space Model ◽  
Mechanical Systems ◽  
Sufficient Conditions ◽  
Uncertain System ◽  
Disturbance Attenuation ◽  
System Model ◽  
Closed Loop System ◽  
Vibration Attenuation

The problems of vibration-attenuation controller design for uncertain mechanical systems with time-varying input delay are of concern in this paper. Firstly, based on matrix transformation, the mechanical system is described as a state-space model. Then, in terms of introducing the linear varying parameters, the uncertain system model is established. Secondly, the LMI-based sufficient conditions for the system to be stabilizable are deduced by utilizing the LMI technique. By solving the obtained LMIs, the controllers are achieved for the closed-loop system to be stable with a prescribed level of disturbance attenuation. Finally, numerical examples are given to show the effectiveness of the proposed theorems.

scholarly journals Decentralised PI controller design based on dynamic interaction decoupling in the closed-loop behaviour of a flotation process

2021 ◽  
Vol 11 (6) ◽  
pp. 4865
Author(s):  
Nomzamo Tshemese-Mvandaba ◽  
R. Tzoneva ◽  
M. E. S. Mnguni
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
Design Procedure ◽  
Loop System ◽  
Closed Loop System ◽  
Flotation Process ◽  
Loop Control ◽  
Decoupling Method ◽  
Pi Controllers ◽  
Interconnected Model

An enhanced method for design of decenralised proportional integral (PI) controllers to control various variables of flotation columns is proposed. These columns are multivariable processes characterised by multiple interacting manipulated and controlled variables. The control of more than one variable is not an easy problem to solve as a change in a specific manipulated variable affects more than one controlled variable. Paper proposes an improved method for design of decentralized PI controllers through the introduction of decoupling of the interconnected model of the process. Decoupling the system model has proven to be an effective strategy to reduce the influence of the interactions in the closed-loop control and consistently to keep the system stable. The mathematical derivations and the algorithm of the design procedure are described in detail. The behaviour and performance of the closed-loop systems without and with the application of the decoupling method was investigated and compared through simulations in MATLAB/Simulink. The results show that the decouplers - based closed-loop system has better performance than the closed-loop system without decouplers. The highest improvement (2 to 50 times) is in the steady-state error and 1.2 to 7 times in the settling and rising time. Controllers can easily be implemented.

Passivity-Based Stabilization of Underactuated Mechanical Systems

2013 ◽  
Vol 421 ◽  
pp. 16-22
Author(s):  
Shan Shan Wu ◽  
Wei Huo
Keyword(s):  
Closed Loop ◽  
Control Method ◽  
Controller Design ◽  
Design Method ◽  
Mechanical Systems ◽  
Matching Condition ◽  
Loop System ◽  
Closed Loop System ◽  
Underactuated Mechanical Systems ◽  
Stabilization Control

A new stabilization control method for underactuated linear mechanical systems is presented in this paper. By proper setting the desired closed-loop system, the matching condition for controller design is reduced to one equation and an adjustable parameter (damping coefficient) is introduced to the controller. Stability of the closed-loop system is proved based on passivity. As an application example, stabilization control of 2-DOF Pendubot is studied. The system is linearized at its equilibrium point and the proposed controller design method is applied to the linearized system. The procedure of solving matching condition and design controller for the Pendubot is provided. The simulation results verify feasibility of the proposed method.

A Novel Delay-Independent Robust Adaptive Controller Design for Uncertain Nonlinear Systems With Time-Varying State Delay

2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Hadi Azmi ◽  
Alireza Yazdizadeh
Keyword(s):  
Nonlinear Systems ◽  
Linear Matrix Inequality ◽  
Closed Loop ◽  
Controller Design ◽  
Loop System ◽  
Linear Matrix ◽  
Time Varying ◽  
Matrix Inequality ◽  
System Delay ◽  
Closed Loop System

Abstract In this paper, two novel adaptive control strategies are presented based on the linear matrix inequality for nonlinear Lipschitz systems. The proposed approaches are developed by creatively using Krasovskii stability theory to compensate parametric uncertainty, unknown time-varying internal delay, and bounded matched or mismatched disturbance effects in closed-loop system of nonlinear systems. The online adaptive tuning controllers are designed such that reference input tracking and asymptotic stability of the closed-loop system are guaranteed. A novel structural algorithm is developed based on linear matrix inequality (LMI) and boundaries of the system delay or uncertainty. The capabilities of the proposed tracking and regulation methods are verified by simulation of three physical uncertain nonlinear system with real practical parameters subject to internal or state time delay and disturbance.

Stable observer-based controller design for robust state-feedback pole assignment

2000 ◽  
Vol 214 (4) ◽  
pp. 313-318 ◽  
Author(s):  
G P Liu ◽  
G R Duan ◽  
S Daley
Keyword(s):  
Frequency Domain ◽  
Stability Problem ◽  
State Feedback ◽  
Closed Loop ◽  
Controller Design ◽  
Pole Assignment ◽  
Loop System ◽  
Closed Loop System ◽  
Sensitive Function ◽  
The Stability

The design of stable observer-based controllers for robust pole assignment is addressed in this paper. The stability problem of these dynamical controllers is investigated, which is often ignored during the controller design. A design formulation of stable observer controllers is presented using state-feedback pole assignment techniques. Although the design formulation is principally aimed at the design of a stable controller, the mixed sensitive function in the frequency domain is also considered to improve the robustness of the closed-loop system. This ensures that the closed-loop system has good robustness and the controller is stable.

scholarly journals Decentralized design of interconnected H∞ feedback control systems with quantized signals

2013 ◽  
Vol 23 (2) ◽  
pp. 317-325 ◽  
Author(s):  
Guisheng Zhai ◽  
Ning Chen ◽  
Weihua Gui
Keyword(s):  
Feedback Control ◽  
Control Systems ◽  
Closed Loop ◽  
Loop System ◽  
Disturbance Attenuation ◽  
Closed Loop System ◽  
Attenuation Level ◽  
Feedback Control Systems ◽  
Decentralized Design ◽  
Disturbance Attenuation Level

In this paper, we consider the design of interconnected H∞ feedback control systems with quantized signals. We assume that a decentralized dynamic output feedback has been designed for an interconnected continuous-time LTI system so that the closed-loop system is stable and a desired H∞ disturbance attenuation level is achieved, and that the subsystem measurement outputs are quantized before they are passed to the local controllers. We propose a local-output-dependent strategy for updating the parameters of the quantizers, so that the overall closed-loop system is asymptotically stable and achieves the same H∞ disturbance attenuation level. Both the pre-designed controllers and the parameters of the quantizers are constructed in a decentralized manner, depending on local measurement outputs.

scholarly journals A proportional controller based on clustering theory: an academic example of a machine learning discipline

2018 ◽  
Vol 210 ◽  
pp. 02005
Author(s):  
Leonardo Acho ◽  
Pablo Buenestado
Keyword(s):  
Machine Learning ◽  
Closed Loop ◽  
Controller Design ◽  
Loop System ◽  
Slew Rate ◽  
Closed Loop System ◽  
Real Experiment ◽  
Proportional Controller ◽  
Rate Limit

The main objective of this paper is to present a controller design based on the K-means clustering theory. The controller is realized in such way that when the plant output is located outside of the designed clustering set, the controller forces it to be in it. Moreover, and according to our real experiment applied to stabilize an unstable integrator plant, our controller approach design is also robust against un-vanishing perturbations and nonlinearity effects on the overall closed-loop system such as saturation, slew-rate limit, and limit bandwidth frequency operation.

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