Controller Design of a Distributed Slewing Flexible Structure—A Frequency Domain Approach

1997 ◽  
Vol 119 (4) ◽  
pp. 809-814 ◽  
Author(s):  
S. M. Yang ◽  
J. A. Jeng ◽  
Y. C. Liu
Keyword(s):  
Frequency Domain ◽  
Transfer Functions ◽  
Controller Design ◽  
System Stability ◽  
Feedback Gain ◽  
Flexible Structure ◽  
Control Law ◽  
Discrete Parameter ◽  
Locus Method ◽  
Beam Experiment

The vibration control of a slewing flexible structure by collocated and noncollocated feedback is presented in this paper. A stability criterion derived from the root locus method in frequency domain is applied to predict the closed-loop system stability of the distributed parameter model whose analytical transfer functions are formulated. It is shown that the control law design requires neither distributed state sensing/estimation nor functional feedback gain; moreover, the spillover problem associated with discrete parameter model can be prevented. Implementation of the noncollocated feedback in a slewing beam experiment validates that the control law is effective in pointing accuracy while suppressing the tip vibration.

An Advanced Frequency-Domain Code for BWR Stability Analysis and Design

2013 ◽  
Author(s):  
Behrooz Askari ◽  
George Yadigaroglu
Keyword(s):  
Steady State ◽  
Frequency Domain ◽  
Transfer Functions ◽  
Density Wave ◽  
System Stability ◽  
Reactor Kinetics ◽  
Analysis And Design ◽  
Drift Flux ◽  
Reactor Transfer ◽  
Phase Instabilities

Density Wave Oscillations in BWRs are coupled with the reactor kinetics. A new analytical, frequency-domain tool that uses the best available models and methods for modeling BWRs and analyzing their stability is described. The steady state of the core is obtained first in 3D with two-group diffusion equations and spatial expansion of the neutron fluxes in Legendre polynomials. The time-dependent neutronics equations are written in terms of flux harmonics (nodal-modal equations) for the study of “out-of-phase” instabilities. Considering separately all fuel assemblies divided into a number of axial segments, the thermal-hydraulic conservation equations are solved (drift-flux, non-equilibrium model). The thermal-hydraulics are iteratively fully coupled to the neutronics. The code takes all necessary information from plant files via an interface. The results of the steady state are used for the calculation of the transfer functions and system transfer matrices using extensively symbolic manipulation software (MATLAB). The resulting very large matrices are manipulated and inverted by special procedures developed within the MATLAB environment to obtain the reactor transfer functions that enable the study of system stability. Applications to BWRs show good agreement with measured stability data.

H∞ Controllers With a PID Structure

1990 ◽  
Vol 112 (3) ◽  
pp. 325-336 ◽  
Author(s):  
M. J. Grimble
Keyword(s):  
Optimal Control ◽  
Simple Form ◽  
Pid Controller ◽  
Transfer Functions ◽  
Controller Design ◽  
Design Procedure ◽  
Control Law ◽  
Pid Controller Design ◽  
Computational Procedures ◽  
The Cost

A review is given of the new H∞ Observations Weighted (HOW) optimal control law. The conditions under which the H∞ controller has a PID structure are identified and some implications for PID controller design are discussed. The simple form of this H∞ control law makes it easy to analyse and design. Examples are presented of the design procedure which involves the specification of the cost-function weighting transfer functions. The controller may be applied in applications where fast computational procedures are important.

On the Spillover of Steady State Unbalance Response of a Rotating Shaft Under Velocity Feedback

2005 ◽  
Vol 128 (2) ◽  
pp. 143-147 ◽  
Author(s):  
S. M. Yang ◽  
G. J. Sheu
Keyword(s):  
Steady State ◽  
Controller Design ◽  
System Stability ◽  
Feedback Gain ◽  
Beam Model ◽  
Rotating Shaft ◽  
Velocity Feedback ◽  
Reduced Order ◽  
Rayleigh Beam ◽  
Unbalance Response

It has been stated that a uniform rotating shaft in the Rayleigh beam model has only a finite number of critical speeds and precession modes. This paper presents a controller design of optimal sensor/actuator location and feedback gain for steady state unbalance response of a rotating shaft operating in a speed range. For systems under order-limit constraint such that only part of the precession modes can be included in the reduced-order controller design, the system stability can be evaluated. The example of a hinged-hinged rotating shaft is employed to illustrate the controller design of velocity feedback in collocated and noncollocated senor/actuator configuration. Analyses show that the reduced-order controller not only guarantees the closed loop system stability but also effectively suppress the unbalance response.

Frequency Domain Identification Experiment on a Large Flexible Structure

1989 ◽  
Author(s):  
D.S. Bayard ◽  
F.Y. Hadaegh ◽  
Y. Yam ◽  
R.E. Scheid ◽  
E. Mettler ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Flexible Structure ◽  
Domain Identification ◽  
Frequency Domain Identification

Error analyses of a Multi-Input-Multi-Output cantilever beam test

2021 ◽  
pp. 107754632110337
Author(s):  
Arup Maji ◽  
Fernando Moreu ◽  
James Woodall ◽  
Maimuna Hossain
Keyword(s):  
Transfer Function ◽  
Frequency Domain ◽  
Cantilever Beam ◽  
Transfer Functions ◽  
Linear Superposition ◽  
Transfer Function Matrix ◽  
Error Analyses ◽  
Pseudo Inverse ◽  
Function Matrix

Multi-Input-Multi-Output vibration testing typically requires the determination of inputs to achieve desired response at multiple locations. First, the responses due to each input are quantified in terms of complex transfer functions in the frequency domain. In this study, two Inputs and five Responses were used leading to a 5 × 2 transfer function matrix. Inputs corresponding to the desired Responses are then computed by inversion of the rectangular matrix using Pseudo-Inverse techniques that involve least-squared solutions. It is important to understand and quantify the various sources of errors in this process toward improved implementation of Multi-Input-Multi-Output testing. In this article, tests on a cantilever beam with two actuators (input controlled smart shakers) were used as Inputs while acceleration Responses were measured at five locations including the two input locations. Variation among tests was quantified including its impact on transfer functions across the relevant frequency domain. Accuracy of linear superposition of the influence of two actuators was quantified to investigate the influence of relative phase information. Finally, the accuracy of the Multi-Input-Multi-Output inversion process was investigated while varying the number of Responses from 2 (square transfer function matrix) to 5 (full-rectangular transfer function matrix). Results were examined in the context of the resonances and anti-resonances of the system as well as the ability of the actuators to provide actuation energy across the domain. Improved understanding of the sources of uncertainty from this study can be used for more complex Multi-Input-Multi-Output experiments.

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