Responsible-Eigenvalue Control for Creating Autonomy in Coupled Systems With Delays

2011 ◽  
Author(s):  
Wei Qiao ◽  
Rifat Sipahi
Keyword(s):  
Real Time ◽  
Controller Design ◽  
Linear Time ◽  
Graph Laplacian ◽  
Coupled Systems ◽  
Communication Delays ◽  
Linear Time Invariant ◽  
Time Invariant ◽  
First Time ◽  
Delay Margin

A class of linear time-invariant (LTI) consensus system with multiple agents and identical communication delays among the agents is considered. For this type of system, we recently showed that a responsible eigenvalue (RE) exists determining the amount of delay (delay margin) that the system can withstand without losing stability. In this paper, we use RE to design controllers such that the delay margin of the system increases as the agents make autonomous decisions. This Responsible Eigenvalue-control enables real-time tuning of RE in a way that the system becomes robust against delays. A numerical example demonstrates intriguing results that connect for the first time in the literature the controller design, the features of the associated graph Laplacian, and RE concept.

Design and implementation of decoupled periodic control scheme for a laboratory-based quadruple-tank process

2021 ◽  
pp. 095965182110228
Author(s):  
Jatin K Pradhan ◽  
Arun Ghosh
Keyword(s):  
Real Time ◽  
High Frequency ◽  
Linear Time ◽  
Disturbance Attenuation ◽  
Minimum Phase ◽  
Periodic Control ◽  
Linear Time Invariant ◽  
Control Scheme ◽  
Gain Margin ◽  
Time Invariant

It is well known that linear time-invariant controllers fail to provide desired robustness margins (e.g. gain margin, phase margin) for plants with non-minimum phase zeros. Attempts have been made in literature to alleviate this problem using high-frequency periodic controllers. But because of high frequency in nature, real-time implementation of these controllers is very challenging. In fact, no practical applications of such controllers for multivariable plants have been reported in literature till date. This article considers a laboratory-based, two-input–two-output, quadruple-tank process with a non-minimum phase zero for real-time implementation of the above periodic controller. To design the controller, first, a minimal pre-compensator is used to decouple the plant in open loop. Then the resulting single-input–single-output units are compensated using periodic controllers. It is shown through simulations and real-time experiments that owing to arbitrary loop-zero placement capability of periodic controllers, the above decoupled periodic control scheme provides much improved robustness against multi-channel output gain variations as compared to its linear time-invariant counterpart. It is also shown that in spite of this improved robustness, the nominal performances such as tracking and disturbance attenuation remain almost the same. A comparison with [Formula: see text]-linear time-invariant controllers is also carried out to show superiority of the proposed scheme.

Nonfragile H∞ Output Feedback Controller Design for Linear Systems*

2003 ◽  
Vol 125 (1) ◽  
pp. 117-123 ◽  
Author(s):  
Guang-Hong Yang ◽  
Jian Liang Wang
Keyword(s):  
Output Feedback ◽  
Controller Design ◽  
Linear Time ◽  
Output Feedback Control ◽  
Disturbance Attenuation ◽  
Output Measurement ◽  
Linear Time Invariant ◽  
Measurement Feedback ◽  
Linear Time Invariant Systems ◽  
Time Invariant

This paper is concerned with the nonfragile H∞ controller design problem for linear time-invariant systems. The controller to be designed is assumed to have norm-bounded uncertainties. Design methods are presented for dynamic output (measurement) feedback. The designed controllers with uncertainty (i.e. nonfragile controllers) are such that the closed-loop system is quadratically stable and has an H∞ disturbance attenuation bound. Furthermore, these robust controllers degenerate to the standard H∞ output feedback control designs, when the controller uncertainties are set to zero.

scholarly journals PID Controller Design Based on Global Optimization Technique with Additional Constraints

2016 ◽  
Vol 67 (3) ◽  
pp. 160-168 ◽  
Author(s):  
Stepan Ozana ◽  
Tomas Docekal
Keyword(s):  
Global Optimization ◽  
Pid Controller ◽  
Controller Design ◽  
Linear Time ◽  
Optimization Technique ◽  
Phase Margin ◽  
Linear Time Invariant ◽  
Pid Controller Design ◽  
Static Systems ◽  
Time Invariant

Abstract This paper deals with design of PID controller with the use of methods of global optimization implemented in Matlab environment and Optimization Toolbox. It is based on minimization of a chosen integral criterion with respect to additional requirements on control quality such as overshoot, phase margin and limits for manipulated value. The objective function also respects user-defined weigh coefficients for its particular terms for a different penalization of individual requirements that often clash each other such as for example overshoot and phase margin. The described solution is designated for continuous linear time-invariant static systems up to 4th order and thus efficient for the most of real control processes in practice.

Decentralized controller design by continuous pole placement for neutral time-delay systems

2016 ◽  
Vol 39 (3) ◽  
pp. 297-311 ◽  
Author(s):  
HE Erol ◽  
A İftar
Keyword(s):  
Time Delay ◽  
Controller Design ◽  
Linear Time ◽  
Pole Placement ◽  
Delay Systems ◽  
Time Delay Systems ◽  
Linear Time Invariant ◽  
Assignment Algorithm ◽  
Placement Algorithm ◽  
Time Invariant

The stabilizing decentralized controller design problem for (possibly descriptor-type) linear time-invariant neutral time-delay systems is considered. A design approach, based on the continuous pole placement algorithm and the decentralized pole assignment algorithm, is proposed. A design example is also presented, to demonstrate the proposed approach.

Robust Controller Design for Descriptor-type Time-delay Systems

2021 ◽  
Vol 20 ◽  
pp. 289-294
Author(s):  
Altug Iftar
Keyword(s):  
Time Delay ◽  
Controller Design ◽  
Linear Time ◽  
Delay Systems ◽  
Time Delay Systems ◽  
Robust Controller ◽  
Frequency Dependent ◽  
Stabilizing Controller ◽  
Linear Time Invariant ◽  
Time Invariant

Linear time-invariant descriptor-type time-delay systems are considered. A robust stabilizing controller design approach for such systems is introduced. Uncertainties both in the time-delays and in other system parameters are considered. A frequency-dependent scalar bound on such uncertainties is first derived. Once this bound is found, the controller design is completely based on the nominal model. However, satisfying a scalar frequency-dependent condition, which uses the derived bound, guarantees robust stability. An example is also presented to illustrate the proposed approach

Modal H∞-Control in the Context of a Rotor Being Subject to Unbalance Excitation and Gyroscopic Effect

2013 ◽  
Author(s):  
Rudolf Sebastian Schittenhelm ◽  
Bernd Riemann ◽  
Stephan Rinderknecht
Keyword(s):  
Degrees Of Freedom ◽  
Controller Design ◽  
Linear Time ◽  
Rotational Frequency ◽  
Gyroscopic Effect ◽  
Actual System ◽  
Linear Time Invariant ◽  
Optimal Controllers ◽  
Problem Description ◽  
Time Invariant

H∞-optimal controllers are designed for a rotor being subject to unbalance excitation and gyroscopic effect. The system possesses two unbalance-induced resonances within its operating range. The presence of gyroscopic effect is challenging for linear time invariant controller design because of the associated dependence of the system dynamics on the rotational frequency of the rotor. Controllers thus have to be robust against deviation of the actual system behavior from the controller design point model. For vibration control purposes, there are two piezoelectric actuators installed in one of the two supports of the rotor. The signals of four inductive sensors measuring the displacements of the two discs of the rotor are used for controller design. In this article, H∞-optimal controllers are designed on the basis of input and output weighting as well as weighting of modal degrees of freedom and modal excitations. It is shown that superior control performance is achieved using modal weighting since a more accurate problem description of rotors excited by unbalance is incorporated in controller design. Results in this article show furthermore that it is possible to design well performing H∞-optimal controllers for a gyroscopic rotor by means of iterative controller design without taking model uncertainty directly into account via weighting of certain FRFs of the system to be controlled.

scholarly journals Quadratic Stabilization of LPV System by an LTI Controller Based on ILMI Algorithm

2007 ◽  
Vol 2007 ◽  
pp. 1-9 ◽  
Author(s):  
Wei Xie
Keyword(s):  
Controller Design ◽  
Linear Time ◽  
Admissible Solution ◽  
Linear Matrix ◽  
Linear Parameter Varying ◽  
Linear Time Invariant ◽  
Lpv Control ◽  
Lpv System ◽  
Time Invariant ◽  
Iterative Linear Matrix Inequality

A linear time-invariant (LTI) output feedback controller is designed for a linear parameter-varying (LPV) control system to achieve quadratic stability. The LPV system includes immeasurable dependent parameters that are assumed to vary in a polytopic space. To solve this control problem, a heuristic algorithm is proposed in the form of an iterative linear matrix inequality (ILMI) formulation. Furthermore, an effective method of setting an initial value of the ILMI algorithm is also proposed to increase the probability of getting an admissible solution for the controller design problem.

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