Closed-loop random vibration control of a shaker table with a microcomputer

1994 ◽  
Vol 13 (4) ◽  
pp. 259-266 ◽  
Author(s):  
Ming L. Wang
Keyword(s):  
Vibration Control ◽  
Random Vibration ◽  
Closed Loop

PI Control of HSFDs for Active Control of Rotor-Bearing Systems

1997 ◽  
Vol 119 (3) ◽  
pp. 658-667 ◽  
Author(s):  
J. P. Hathout ◽  
A. El-Shafei
Keyword(s):  
Vibration Control ◽  
Active Control ◽  
Closed Loop ◽  
Rotating Machinery ◽  
Loop System ◽  
Pi Control ◽  
Closed Loop System ◽  
Transient Vibration ◽  
Critical Speeds ◽  
Rotor Bearing

This paper describes the proportional integral (PI) control of hybrid squeeze film dampers (HSFDS) for active control of rotor vibrations. Recently it was shown that the automatically controlled HSFD based on feedback of rotor speed can be a very efficient device for active control of rotor vibration when passing through critical speeds. Although considerable effort has been put into the study of steady-state vibration control, there are few methods in the literature applicable to transient vibration control of rotor-bearing systems. Rotating machinery may experience dangerously high dynamic loading due to the sudden mass unbalance that could be associated with blade loss. Transient run-up and coast down through critical speeds when starting up or shutting down rotating machinery induces excessive bearing loads at criticals. In this paper, PI control is proposed as a regulator for the HSFD system to attenuate transient vibration for both sudden unbalance and transient runup through critical speeds. A complete mathematical model of this closed-loop system is simulated on a digital computer. Results show an overall enhanced behavior for the closed-loop rotor system. Gain scheduling of both the integral gain and the reference input is incorporated into the closed-loop system with the PI regulator and results in an enhanced behavior of the controlled system.

Analysis of low damping ratios in multi-exciter stationary non-Gaussian random vibration control

2020 ◽  
Vol 26 (17-18) ◽  
pp. 1463-1470 ◽  
Author(s):  
Ronghui Zheng ◽  
Huaihai Chen ◽  
Min Qin ◽  
Andrea Angeli ◽  
Dirk Vandepitte
Keyword(s):  
Vibration Control ◽  
Random Vibration ◽  
Response Spectra ◽  
Spectral Lines ◽  
Control Algorithms ◽  
Calculation Error ◽  
Spectral Matrix ◽  
At Resonance ◽  
Input Signals ◽  
Non Gaussian

This article investigates the influence of low damping ratios on the performance of the multi-exciter stationary non-Gaussian random vibration control system. The basic theory of the multi-exciter stationary non-Gaussian random vibration method is reviewed first, and then the influences of low damping ratios on multi-output spectra and kurtoses are analyzed. The low damping ratios cause an ill-conditioned problem which will make the drive spectral matrix solution inaccurate; thus, some spectral lines located at resonance peaks in the response spectra cannot be modified within the preset tolerances by the control algorithms. The regularization method is used to alleviate the calculation error. The output kurtoses are dependent not only on the characteristics of the system but also on the input signals. It is found that the kurtosis control will be intractable if the damping ratios are very low. A two-input two-output cantilever beam simulation example is described to illustrate the analysis results.

Reliability-Based Analysis of Frequency of Closed-Loop Vibration Control Systems with Interval Parameters

2014 ◽  
Vol 644-650 ◽  
pp. 53-57
Author(s):  
Jin Gang Liu ◽  
Shi Peng Wang ◽  
Zhong Jun Zhang ◽  
Da Wei Jin ◽  
Feng Xiao Huang ◽  
...  
Keyword(s):  
Distribution Function ◽  
Vibration Control ◽  
Control Systems ◽  
Present Method ◽  
Closed Loop ◽  
Uncertain Parameters ◽  
Convex Model ◽  
Interval Parameters ◽  
Closed Loop Systems ◽  
Random Eigenvalues

Using the convex model theory, the reliability-based analysis of frequency of the vibration control problem of structures with Interval parameters is discussed. Based on the theory of perturbation method, reliability analysis, and PNET method, the method of reliability-based analysis of eigenvalues of closed-loop vibration control systems with uncertain parameters is studied. And the distribution function of the random eigenvalues will not be computed other than their means and variances. The standard deviations of eigenvalues of the uncertain closed-loop systems can be used to estimate the reliability of frequency. The numerical results show that the present method is effective.

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