A Case Study in Control Methods for Active Magnetic Bearings

2014 ◽  
Author(s):  
Alexander H. Pesch ◽  
Stephen P. Hanawalt ◽  
Jerzy T. Sawicki
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
Experimental System ◽  
Magnetic Bearings ◽  
Control Law ◽  
Active Magnetic Bearings ◽  
Active Feedback ◽  
Active Feedback Control ◽  
Amb System

Active magnetic bearings (AMBs) provide support to rotating machinery through magnetic forces which are regulated through active feedback control. As AMBs continue to establish themselves as a proven technology, many classical and modern techniques are being employed to address the design of the control law. The current work studies three of the controller design techniques which are common in the literature for AMB applications: PID, LQG, and μ-synthesis. A controller is designed for an AMB system using each of the three techniques. Details of the design processes are given and the resulting controllers are compared. Finally, the controllers are implemented on the experimental system and the closed-loop characteristics are measured and evaluated. This work provides a common case study to demonstrate the strengths and weaknesses of PID, LQG, and μ-synthesis control methodologies as applied to a specific AMB system.

LQG-Based Robust Control of Active Automobile Suspension

2003 ◽  
Author(s):  
H. Porumamilla ◽  
A. G. Kelkar
Keyword(s):  
Closed Loop ◽  
Ride Comfort ◽  
Controller Design ◽  
Control Design ◽  
Suspension System ◽  
Robust Controller ◽  
Automobile Suspension ◽  
Active Feedback ◽  
Active Feedback Control ◽  
Robust Controller Design

This paper presents robust controller design for an active automobile suspension system using an interative LQG design technique. The main objective is to design an active feedback control for an automobile suspension system to ensure the ride comfort for passengers in the presence of unknown road disturbances. The control system designed is shown to be robust to uncertainties and parametric variations. The resulting interative LQG-based control design is shown to achieve a significant improvement in the performance, while maintaining a desired level of closed-loop stability that is robust to plant uncertainties and parametric variations. The controller design is also compared to some other active suspension designs published in the literature.

scholarly journals H-infinity controller design for active magnetic bearings considering nonlinear vibrational rotordynamics

2017 ◽  
Vol 4 (5) ◽  
pp. 16-00716-16-00716 ◽  
Author(s):  
Matthew O. T. COLE ◽  
Chakkapong CHAMROON ◽  
Patrick S. KEOGH
Keyword(s):  
Controller Design ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
H Infinity

Dynamic Modeling and Analysis of Active Magnetic Bearings

2014 ◽  
Vol 494-495 ◽  
pp. 685-688
Author(s):  
Rong Gao ◽  
Gang Luo ◽  
Cong Xun Yan
Keyword(s):  
Dynamic Characteristic ◽  
Dynamic Modeling ◽  
Magnetic Bearing ◽  
Integrated System ◽  
Magnetic Bearings ◽  
Active Magnetic Bearing ◽  
Active Magnetic Bearings ◽  
Modeling And Analysis ◽  
Amb System ◽  
Mathematics Method

Active magnetic bearing (AMB) system is a complex integrated system including mechanics, electronic and magnetism. In order to research for the basic dynamic characteristic of rotor supported by AMB, it is necessary to present mathematics method. The dynamics formula of AMB is established using theory means of dynamics of rotator and mechanics of vibrations. At the same tine, the running stability of rotor is analyzed and the example is presented in detail.

Stability and Response of Rotors Supported on Active Magnetic Bearings

1993 ◽  
Author(s):  
K. Ramesh ◽  
R. G. Kirk
Keyword(s):  
Finite Element ◽  
Stability Analysis ◽  
Transfer Matrix ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Finite Element Program ◽  
Element Program ◽  
Matrix Codes ◽  
The Stability

Abstract A PC-based program has been developed which is capable of performing stability analysis and response calculations of rotor-bearing systems. The paper discusses the modeling of rotors supported on active magnetic bearings (AMB) and highlights the advantages in the modeling using the finite element method, over the transfer matrix method. An 8-stage centrifugal compressor supported on AMB was chosen for the case study. The results for the stability analysis, obtained using the finite element program was compared with those obtained by the well established transfer matrix codes. The results of unbalance response, including the effects of sensor non collocation are presented and this demonstrates how an AMB supported rotor can experience a synchronous instability for selected sensor locations and balance distributions.

Active Feedback Control Using Adaptive Filtering

2004 ◽  
Vol 10 (1) ◽  
pp. 25-38
Author(s):  
Fenglin Wang ◽  
Chris K Mechefske
Keyword(s):  
Feedback Control ◽  
Closed Loop ◽  
Noise Control ◽  
Active Noise Control ◽  
Experimental Studies ◽  
Loop Control ◽  
Active Noise ◽  
Active Feedback ◽  
Loop Control System ◽  
Active Feedback Control

In this paper we apply a filtered-X algorithm to an active feedback control structure and derive the transfer function of a closed-loop control system. Simulation studies are then carried out on the closed-loop property while varying the parameters (input frequency, delays in plant, amplitude and phase of modeling filter). Several properties of adaptive feedback control are revealed. Experimental studies on feedback active noise control of noise in a finite duct and a small enclosure are described, and outstanding active noise control effects are achieved. Experimental results of closed-loop frequency response are also provided.

Multiharmonic Adaptive Vibration Control of Misaligned Driveline via Active Magnetic Bearings

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Hans A. DeSmidt ◽  
K. W. Wang ◽  
Edward C. Smith
Keyword(s):  
Vibration Control ◽  
Closed Loop ◽  
Explicit Knowledge ◽  
Operating Conditions ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Load Torque ◽  
Stability Robustness ◽  
Adaptive Vibration Control ◽  
Loop Stability

Active magnetic bearings (AMBs) have been proposed by many researchers and engineers as an alternative to replace traditional contact bearings in rotor and driveshaft systems. Such active, noncontact bearings do not have frictional wear and can be used to suppress vibration in sub- and supercritical rotor-dynamic applications. One important issue that has not yet been addressed by previous AMB-driveline control studies is the effect of driveline misalignment. Previous research has shown that misalignment causes periodic parametric and forcing actions, which greatly impact both driveline stability and vibration levels. Therefore, in order to ensure closed-loop stability and acceptable performance of any AMB controlled driveline subjected to misalignment, these effects must be accounted for in the control system design. In this paper, a hybrid proportional derivative (PD) feedback/multiharmonic adaptive vibration control (MHAVC) feedforward law is developed for an AMB/U-joint-driveline system, which is subjected to parallel-offset misalignments, imbalance, and load-torque operating conditions. Conceptually, the PD feedback ensures closed-loop stability while the MHAVC feedforward suppresses steady-state vibration. It is found that there is a range of P and D feedback gains that ensures both MHAVC convergence and closed-loop stability robustness with respect to shaft internal damping induced whirl and misalignment effects. Finally, it is analytically and experimentally demonstrated that the hybrid PD-MHAVC law effectively adapts to and suppresses multiharmonic vibration induced by imbalance, misalignment, and load-torque effects at multiple operating speeds without explicit knowledge of the disturbance conditions.

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