A Multiobjective Adaptive Controller for Magnetic Bearing Systems

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
M. Necip Sahinkaya ◽  
Abdul-Hadi G. Abulrub ◽  
Clifford R. Burrows ◽  
Patrick S. Keogh
Keyword(s):  
Adaptive Controller ◽  
Optimization Method ◽  
Magnetic Bearing ◽  
System Stability ◽  
Flexible Rotor ◽  
Whole Process ◽  
Performance Specifications ◽  
Displacement Transducers ◽  
Value Decomposition

The paper considers three issues in flexible rotor and magnetic bearing systems, namely, the control of rotor vibration, control of transmitted forces, and prevention of rotor contact with auxiliary bearings. An adaptive multiobjective optimization method is developed to tackle these issues simultaneously using a modified recursive adaptive controller. The proposed method involves automatic tuning of the weighting parameters in accordance with performance specifications. A two-stage weighting strategy is implemented, involving base weightings, calculated from a singular value decomposition of the system’s receptance matrices, and two adjustable weighting parameters to shift the balance between the three objective functions. The receptance matrices are functions of rotational speed and they are estimated in situ. The whole process does not require prior knowledge of the system parameters. Real-time implementation of the proposed controller is explained and tested by using an experimental flexible rotor magnetic bearing system. The rotor displacements were measured relative to the base frame using four pairs of eddy current displacement transducers. System stability is ensured through local PID controllers. The proposed adaptive controller is implemented in parallel, and the effectiveness of the weighting parameters in changing the balance between the transmitted forces and rotor vibrations is demonstrated experimentally.

A Multi-Objective Adaptive Controller for Magnetic Bearing Systems

2009 ◽  
Author(s):  
M. Necip Sahinkaya ◽  
Abdul-Hadi G. Abulrub ◽  
Clifford R. Burrows ◽  
Patrick S. Keogh
Keyword(s):  
Adaptive Controller ◽  
Optimization Method ◽  
Magnetic Bearing ◽  
Open Loop ◽  
System Stability ◽  
Flexible Rotor ◽  
Multi Objective ◽  
Whole Process ◽  
Performance Specifications ◽  
Value Decomposition

The paper considers three issues in flexible rotor and magnetic bearing systems, namely control of rotor vibration, control of transmitted forces, and prevention of rotor contact with auxiliary bearings. An adaptive multi-objective optimization method is developed to tackle these issues simultaneously using a modified recursive open loop adaptive controller. The proposed method involves automatic tuning of the weighting parameters in accordance with performance specifications. A two-stage weighting strategy is implemented involving base weightings, calculated from a singular value decomposition of the system’s receptance matrices, and two adjustable weighting parameters to shift the balance between the three objective functions. The receptance matrices are functions of rotational speed and they are estimated in situ. The whole process does not require prior knowledge of the system parameters. Real-time implementation of the proposed controller is explained and tested by using an experimental flexible rotor magnetic bearing system. The rotor displacements were measured relative to the base frame using four pairs of eddy current displacement transducers. System stability is ensured through local PID controllers. The proposed adaptive controller is implemented in parallel and the effectiveness of the weighting parameters in changing the balance between the transmitted forces and rotor vibrations is demonstrated experimentally.

An Adaptive Multi-Objective Controller for Flexible Rotor and Magnetic Bearing Systems

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
M. Necip Sahinkaya ◽  
Abdul-Hadi G. Abulrub ◽  
Clifford R. Burrows
Keyword(s):  
Adaptive Strategy ◽  
Adaptive Controller ◽  
Magnetic Bearing ◽  
Open Loop ◽  
Multi Objective ◽  
Performance Specifications ◽  
Weighting Strategy ◽  
Value Decomposition ◽  
And Control ◽  
Experimental Rig

This paper considers two issues in the vibration of rotating machines, namely, control of rotor vibration and control of the forces transmitted to the base. An adaptive multi-objective method is developed to tackle these issues simultaneously using magnetic bearings. A two-stage weighting strategy is developed, involving base weightings calculated by using a singular value decomposition of the system’s receptance matrices and an adjustable single weighting parameter tuned automatically to shift the balance between the two objective functions in accordance with performance specifications. This new real-time controller does not require measurements in addition to those required for the open-loop adaptive strategy. Frequency and time domain simulations of an existing experimental rig are used to assess the effectiveness of the proposed multi-objective adaptive controller as a precursor to an experimental study.

Eddy Current Effects on the Design of Rotor-Magnetic Bearing Systems

1995 ◽  
Vol 117 (B) ◽  
pp. 162-170 ◽  
Author(s):  
C. Kim ◽  
A. B. Palazzolo ◽  
A. Kascak ◽  
G. Brown
Keyword(s):  
Eddy Current ◽  
Magnetic Bearing ◽  
System Stability ◽  
Design Tools ◽  
Test Results ◽  
Flexible Rotor ◽  
New Methods ◽  
Novel Approach ◽  
Accurate Design ◽  
Effective Operation

The recent growth of magnetic bearing applications in the chemical, utility and aerospace industries requires more accurate design tools to insure reliable and effective operation as components of the overall rotor bearing system. This paper provides a novel approach for simulating a flexible rotor suspended in magnetic bearings, accounting for eddy current effects. The manuscript discusses some magnetic bearing fundamentals, leading up to the new methods for modeling. Test results show very good correlation with theory and confirm the importance of considering eddy current effects. Surface conductivity and frequency dependent permeability effects on the B field in the magnet gaps are shown to be very significant on overall system stability. The results in the manuscript should be very useful to the design or test rotor dynamicist.

Eddy Current Effects on the Design of Rotor-Magnetic Bearing Systems

1995 ◽  
Vol 117 (B) ◽  
pp. 162-170 ◽  
Author(s):  
C. Kim ◽  
A. B. Palazzolo ◽  
A. Kascak ◽  
G. Brown
Keyword(s):  
Eddy Current ◽  
Magnetic Bearing ◽  
System Stability ◽  
Design Tools ◽  
Test Results ◽  
Flexible Rotor ◽  
New Methods ◽  
Novel Approach ◽  
Accurate Design ◽  
Effective Operation

The recent growth of magnetic bearing applications in the chemical, utility and aerospace industries requires more accurate design tools to insure reliable and effective operation as components of the overall rotor bearing system. This paper provides a novel approach for simulating a flexible rotor suspended in magnetic bearings, accounting for eddy current effects. The manuscript discusses some magnetic bearing fundamentals, leading up to the new methods for modeling. Test results show very good correlation with theory and confirm the importance of considering eddy current effects. Surface conductivity and frequency dependent permeability effects on the B field in the magnet gaps are shown to be very significant on overall system stability. The results in the manuscript should be very useful to the design or test rotor dynamicist.

Identification of Bearing Coefficients of Flexible Rotor-Bearing Systems

2000 ◽  
Author(s):  
Tachung Yang ◽  
Wei-Ching Chaung
Keyword(s):  
Industrial Applications ◽  
Operating Conditions ◽  
Least Square ◽  
Flexible Rotor ◽  
Fem Modeling ◽  
Identification Method ◽  
Reaction Forces ◽  
Manufacturing Assembly ◽  
Stiffness And Damping

The accuracy of stiffness and damping coefficients of bearings is critical for the rotordynamic analysis of rotating machinery. However, the influence of bearings depends on the design, manufacturing, assembly, and operating conditions of the bearings. Uncertainties occur quite often in manufacturing and assembly, which causes the inaccuracy of bearing predictions. An accurate and reliable in-situ identification method for the bearing coefficients is valuable to both analyses and industrial applications. The identification method developed in this research used the receptance matrices of flexible shafts from FEM modeling and the unbalance forces of trial masses to derive the displacements and reaction forces at bearing locations. Eight bearing coefficients are identified through a Total Least Square (TLS) procedure, which can handle noise effectively. A special feature of this method is that it can identify bearing coefficients at a specific operating speed, which make it suitable for the measurement of speed-dependent bearings, like hydrodynamic bearings. Numerical validation of this method is presented. The configurations of unbalance mass arrangements are discussed.

Study on Dent Resistance with Whole Process Optimization Method for Body's Cover Based on the Variable Conditions

2013 ◽  
Vol 700 ◽  
pp. 164-169
Author(s):  
Kai Song ◽  
Chao Wang ◽  
Tao Chen ◽  
Ze Zhou
Keyword(s):  
Process Optimization ◽  
Optimization Problems ◽  
Simulation Method ◽  
Optimization Method ◽  
Fast Simulation ◽  
Whole Process ◽  
Element Simulation ◽  
Contact Nonlinearity ◽  
Abaqus Software ◽  
Process Method

This paper aims at cover body dent resistance optimization problems, developed a whole process method using the finite element simulation method and the corresponding engineering experience to solve the dent resistance problem. Use of Tcl/Tk language to develop the script for fast simulation model consider material nonlinearity and contact nonlinearity, Use Abaqus software to calculate the results, and then customized to optimize use of simplified script parameters on changes in the working conditions of the structure will be optimized. The results show that this set of process optimization method to solve the variable conditions dent resistance is quickly, efficiently and accurately.

Dynamic Analysis of Flexible Rotor Suspended by Active Magnetic Bearings With LQR Controller

2018 ◽  
Author(s):  
Yixin Su ◽  
Yanhui Ma ◽  
Qian Shi ◽  
Suyuan Yu
Keyword(s):  
Dynamic Characteristics ◽  
Beam Theory ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Flexible Rotor ◽  
Linear Quadratic ◽  
State Response ◽  
Lagrange’S Equation ◽  
Linear Quadratic Regulation ◽  
Lqr Controller

Dynamic characteristics of active magnetic bearing (AMB)-flexible rotor system are closely related to control law. To analyze dynamic characteristics of flexible rotor suspended by AMBs with linear quadratic regulation (LQR) controller, a simple and effective method based on numerical calculation of unbalanced response is proposed in this article. The model of flexible rotor is established based upon Euler-Bernoulli beam theory and Lagrange’s equation. Disc on the rotor and its Gyro effect are taken into account. LQR controller based on error and its derivative is developed to control electromagnetic force of AMB at each degree of freedom (DOF) in real time. Under the unbalanced exciting force, the steady-state response and transient response in time domain of each node of flexible rotor at 0–4000 rad/s are calculated numerically. The critical speeds of rotor are obtained by identification method quickly and easily.

Controlling Chaos by Hybrid System Based on FREN and Sliding Mode Control

2005 ◽  
Vol 128 (2) ◽  
pp. 352-358 ◽  
Author(s):  
C. Treesatayapun ◽  
S. Uatrongjit
Keyword(s):  
Sliding Mode ◽  
Adaptive Controller ◽  
Descent Method ◽  
Fuzzy Rules ◽  
System Stability ◽  
Steepest Descent Method ◽  
Upper And Lower Bounds ◽  
Adaptation Algorithm ◽  
Control Effort ◽  
Fine Tune

This paper presents a direct adaptive controller for chaotic systems. The proposed adaptive controller is constructed using the network called fuzzy rules emulated network (FREN). FREN’s structure is based on human knowledge in the form of fuzzy rules. Parameter adaptation algorithm based on the steepest descent method is presented to fine tune the controller’s performance. To improve the system stability, the modified sliding mode algorithm is applied to estimate the upper and lower bounds of the control effort. The suitable control effort is generated by FREN and kept within these bounds. Some computer simulations of using the controller to control the Hénon map have been performed to demonstrate the performance of the proposed controller.

scholarly journals The Active Magnetic Bearing Enables Optimum Damping of Flexible Rotor

1984 ◽  
Author(s):  
Helmut Habermann ◽  
Maurice Brunet
Keyword(s):  
Control System ◽  
Rotation Axis ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Flexible Rotor ◽  
Mechanical Contact ◽  
Electronic Control System ◽  
Electromagnetic Coils ◽  
Automatic Balancing ◽  
Ferromagnetic Ring

The active magnetic bearing is based on the use of forces created by a magnetic field to levitate the rotor without mechanical contact between the stationary and moving parts. A ferromagnetic ring fixed on the rotor “floats” in the magnetic fields generated by the electromagnets, which are mounted as two sets of opposing pairs. The current is transmitted to the electromagnetic coils through amplifiers. The four electromagnets control the rotor’s position in response to the signals transmitted from the sensors. The rotor is maintained in equilibrium under the control of the electromagnetic forces. Its position is determined by means of sensors which continuously monitor any displacements through an electronic control system. As in every control system, damping of the loop is provided by means of a phase advance command from one or more differenciating circuits of the position error signal. The capability of modifying the electromagnetic force both in terms of amplitude and phase leads to the benefit of specific properties for the application, in particular: - automatic balancing characterized by the rotation of the moving part around its main axis of inertia, and not around the axis of the bearings allowing operation without vibrations, - adjustable damping of the suspension allowing easy passing of the critical speeds of the rotor, - high and adjustable stiffness yielding maximum accuracy of rotor equilibrium position, - permanent diagnosis of machine operation due to the knowledge of all rotation characteristics (speed, loads on the bearings, position of the rotation axis, eccentricity, out-of-balance, disturbance frequency).

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