A Minimal Controller Synthesis Algorithm for Narrow-Band Applications

2005 ◽  
Vol 219 (8) ◽  
pp. 591-607 ◽  
Author(s):  
A J Hillis ◽  
S A Neild ◽  
D P Stoten ◽  
A J L Harrison
Keyword(s):  
Vibration Isolation ◽  
Narrow Band ◽  
Broad Band ◽  
Control Synthesis ◽  
Error Signal ◽  
Engine Mounts ◽  
Common Control ◽  
Integral Action ◽  
Active Vibration ◽  
And Performance

A common control problem is that of reducing a narrow-band error signal or a narrow-band component of a broad-band error signal. The particular application described in this paper is that of active vibration isolation for automotive vehicles. The error-driven minimal control synthesis (Er-MCSI) algorithm with integral action has been applied to this problem, but is known to exhibit gain windup. The nature of the gain windup phenomenon is investigated and methods to mitigate its effects are discussed. A new controller, the narrow-band MCS (NBMCS), is developed specifically for narrow-band applications. NBMCS is based upon Er-MCSI and exploits the deterministic nature of the system disturbance. The NBMCS algorithm is shown not to suffer from the gain windup problem. The properties and performance of the Er-MCSI and NBMCS controllers are compared analytically, via simulation and experimental application, to an automotive vehicle equipped with active engine mounts.

Gain-Scheduled ℋ∞-Control for Active Vibration Isolation of a Gyroscopic Rotor

2015 ◽  
Author(s):  
Fabian B. Becker ◽  
Martin A. Sehr ◽  
Stephan Rinderknecht
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Linear Time ◽  
Displacement Sensors ◽  
Active Vibration ◽  
And Performance ◽  
Gyroscopic Effects ◽  
Gain Scheduled ◽  
Active Vibration Isolation

This paper deals with active vibration isolation of unbalance-induced oscillations in rotors using gain-scheduled H∞-controller via active bearings. Rotating machines are often exposed to gyroscopic effects, which occur due to bending deformations of rotors and the consequent tilting of rotor disks. The underlying gyroscopic moments are proportional to the rotational speed and couple the rotor’s radial degrees of freedom. Accordingly, linear time-varying models are well suited to describe the system dynamics in dependence on changing rotational speeds. In this paper, we design gain-scheduled H∞-controllers guaranteeing both robust stability and performance within a predefined range of operating speeds. The paper is based on a rotor test rig with two unbalance-induced resonances in its operating range. The rotor has two discs and is supported by one active and one passive bearing. The active support consists of two piezoelectric stack actuators and two collocated piezoelectric load washers. In addition, the rig is equipped with four inductive displacement sensors located at the discs. Closed-loop performance is assessed via isolation of unbalance-induced vibrations using both simulation and experimental data. This contribution is the next step on our path to achieving the long-term objective of combined vibration attenuation and isolation.

Active Vibration Isolation Control for Narrow-Band Frequency Disturbances

2005 ◽  
Vol 71 (705) ◽  
pp. 1537-1543
Author(s):  
Yuichi CHIDA ◽  
Yoshiyuki ISHIHARA ◽  
Takuya OKINA ◽  
Ryou FURUKAWA ◽  
Koichi OHTOMI
Keyword(s):  
Vibration Isolation ◽  
Narrow Band ◽  
Band Frequency ◽  
Active Vibration ◽  
Active Vibration Isolation

The Broad-Band Active Vibration Control Systems With Controllable Damping for Non-Conservative Self-Excited Structures

1991 ◽  
Author(s):  
S. V. Kravchenko
Keyword(s):  
Vibration Control ◽  
Control Systems ◽  
Narrow Band ◽  
Active Vibration Control ◽  
Broad Band ◽  
Dynamic Force ◽  
Optimal Control Strategy ◽  
Active Vibration ◽  
Feedback Synthesis ◽  
Conveying Fluid

Abstract The features of active vibration control applied to self-excited non-conservative mechanical systems (such as structures subject to flatter, rotor machines, tubes conveying fluid) are discussed. It has been found that the optimal control strategy is the broad-band compensation of the dynamic force reactions combined with narrow-band damping of the mechanical structure resonant vibration. Some problems of feedback synthesis are solved analytically for these systems. The importance of symmetry and asymmetry for the active vibration control systems is discussed. In the case of self-excited systems, it is possible to use the small asymmetry of the control system for the stabilization of the dynamic process.

Dynamics Enhancements of Advanced LIGO Multi-Stage Active Vibration Isolators and Related Control Performance Improvement

2012 ◽  
Author(s):  
Fabrice Matichard ◽  
Ken Mason ◽  
Richard Mittleman ◽  
Brian Lantz ◽  
Ben Abbott ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Experimental Results ◽  
Dynamical Response ◽  
Control Performance ◽  
Vibration Isolators ◽  
Multi Stage ◽  
Final Design ◽  
Active Vibration ◽  
And Performance ◽  
Isolation Systems

The control bandwidth and performance of active vibration isolation systems are usually directly related to the system dynamic characteristics. In this paper, we present results from a 4 years study carried out to improve the dynamical response and control performance on the two-stage isolator designed for Advanced LIGO detectors. The paper will focus on the platform’s first stage to illustrate prototyping, optimization, final design and the experimental results obtained during this program. The system concept, architecture and prototype will be presented. The factors initially limiting the prototype’s performance will be analyzed. Solutions based on sensors relocation, payload reduction, structural stiffening and passive techniques to damp the residual high frequency flexible modes will be presented. Experimental results obtained with the prototype will be compared with the system’s final version. The series of improvement obtained help not only to increase the system’s bandwidth, robustness and performance but also to simplify and speed up the control commissioning, which is very important for the Advanced LIGO project that will be using 5 of these platforms in each of its 3 detectors.

Active Vibration Isolation of Metrology Frames; A Modal Decoupled Control Design

2005 ◽  
Vol 127 (3) ◽  
pp. 223-233 ◽  
Author(s):  
Marcel Heertjes ◽  
Koen de Graaff ◽  
Jan-Gerard van der Toorn
Keyword(s):  
Vibration Isolation ◽  
Isolation System ◽  
Single Input Single Output ◽  
Single Output ◽  
System A ◽  
Active Vibration ◽  
Single Input ◽  
And Performance ◽  
Six Degree Of Freedom ◽  
Active Vibration Isolation

For a six degree-of-freedom active vibration isolation system, a control strategy based on modal decoupling is proposed. This has the advantage of controlling the modal directions on a centralized single-input single-output basis. As a consequence, stability and performance can be imposed in each of the modal directions separately. An experimental demonstration is given using a dummy metrology frame. That is, a 1600 kg payload mass supported by three combined pneumatic and Lorentz controlled isolators. With this setup, two unstable modal directions resulting from a high center of gravity are stabilized without compromising performance in any of the remaining directions. In fact, performance in the remaining directions is enhanced using manual loop shaping.

The Problems of Active Vibration Isolation in Nonlinear and Parametric Structures

1991 ◽  
Author(s):  
K. V. Frolov
Keyword(s):  
Vibration Control ◽  
Vibration Isolation ◽  
Active Vibration Control ◽  
Broad Band ◽  
Nonlinear Phenomena ◽  
Excited Vibration ◽  
Nonlinear Mechanical ◽  
Spectrum Transformation ◽  
Active Vibration ◽  
First Time

Abstract The theory of active vibration control based on the principle of broad-band compensation coupled with controllable vibration damping is presented. The applications of this principle to parametric and nonlinear mechanical structures are discussed. For the first time the possibility of the active vibration control with the aid of stochastic self-excited vibration spectrum transformation nonlinear phenomena is investigated. The theoretical and experimental results are compared for various complex mechanical objects.

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