scholarly journals Numerical and Experimental Modal Control of Flexible Rotor Using Electromagnetic Actuator

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Edson Hideki Koroishi ◽  
Adriano Silva Borges ◽  
Aldemir Ap Cavalini ◽  
Valder Steffen
Keyword(s):  
Linear Quadratic Regulator ◽  
Electromagnetic Actuator ◽  
Modal Control ◽  
Flexible Rotor ◽  
Linear Quadratic ◽  
Rotating System ◽  
Present Contribution ◽  
Flexible Rotors ◽  
Hybrid Bearing

The present work is dedicated to active modal control applied to flexible rotors. The effectiveness of the corresponding techniques for controlling a flexible rotor is tested numerically and experimentally. Two different approaches are used to determine the appropriate controllers. The first uses the linear quadratic regulator and the second approach is the fuzzy modal control. This paper is focused on the electromagnetic actuator, which in this case is part of a hybrid bearing. Due to numerical reasons it was necessary to reduce the size of the model of the rotating system so that the design of the controllers and estimator could be performed. The role of the Kalman estimator in the present contribution is to estimate the modal states of the system and to determine the displacement of the rotor at the position of the hybrid bearing. Finally, numerical and experimental results demonstrate the success of the methodology conveyed.

Theoretical and Experimental Studies on Squeeze Film Stabilizers for Flexible Rotor-Bearing Systems Using Newtonian and Viscoelastic Lubricants

1990 ◽  
Vol 112 (4) ◽  
pp. 473-482 ◽  
Author(s):  
B. Halder ◽  
A. Mukherjee ◽  
R. Karmakar
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Squeeze Film ◽  
Experimental Investigations ◽  
Flexible Rotor ◽  
Stability Range ◽  
High Speeds ◽  
Flexible Rotors ◽  
Rotor Bearing

A combination of a squeeze film damper and a plane journal bearing is studied as a stabilizing scheme. The damper is made to play the role of a stabilizer to postpone the instability threshold speeds of flexible rotors. Both Newtonian and viscoelastic fluids are used in the rotor-bearing system. Dynamics of the system is theoretically analyzed using bond graphs. Analysis reveals that the use of a Newtonian fluid in the stabilizer largely improves the high speed stability range. However, viscoelastic stabilizing fluid has a detrimental effect on highly flexible rotors. Experimental investigations, conducted on a flexible rotor (natural frequency, 30 Hz), confirm the theoretical findings. In addition, experiments indicate that though the use of viscoelastic stabilizing fluids leads to instability in flexible rotors, the growth of large amplitude whirl is postponed to very high speeds.

Delayed Reference Control of a Two-Mass Elastic System

2004 ◽  
Vol 10 (1) ◽  
pp. 135-159 ◽  
Author(s):  
P Gallina ◽  
Alberto Trevisani
Keyword(s):  
Elastic System ◽  
Linear Quadratic Regulator ◽  
Primary Concern ◽  
Linear Quadratic ◽  
Mass System ◽  
Control Scheme ◽  
Optimal Linear ◽  
Reference Parameter ◽  
The Stability

An innovative non-time-based control scheme for path tracking and vibration control of a two-mass system is introduced in this paper. The basic idea of the scheme, called delayed reference control (DRC), is to make the path reference of the system be a function of an action reference parameter which depends both on time and a variable which plays the role of a time delay. By suitably computing the value of the delay on the basis of the vibration measured, such vibration can be actively suppressed while an independent position regulator ensures an accurate tracking of the desired path. The DRC scheme is therefore suitable for those applications, in particular in the robotic field, where a pre-defined path through space must be followed precisely while the time taken to carry out the task is not a primary concern. In this paper the stability of the system is investigated, and numerical results are provided to assess the performance of the proposed method, compared to that of an optimal linear quadratic regulator.

Stability of Flexible Rotors With a LeBlanc Balancer

2011 ◽  
Author(s):  
Leonardo Urbiola-Soto ◽  
Marcelo Lopez-Parra
Keyword(s):  
High Speed ◽  
Particle Image ◽  
Flexible Rotor ◽  
Rotating System ◽  
Stability Behavior ◽  
Piv Technique ◽  
Flexible Rotors ◽  
Image Velocimetry ◽  
The Stability ◽  
Stability Limits

Although the liquid balancer has nearly a century of having been introduced by LeBlanc, little information is available on the dynamic response and stability behavior of this kind of device. Earlier author’s research using a high-speed camera and a Particle Image Velocimetry (PIV) technique showed the existence of a fluid backward traveling wave inside the balancer cavity. This damping phenomenon helps enhance the unbalance response of the rotating system and also raises the stability limits. This paper shows that a flexible rotor employing a LeBlanc balancer has remarkable increase in the threshold speed of instability for aerodynamic cross-coupling and viscous internal friction damping.

EXPERIMENTAL FUZZY MODAL CONTROL OF FLEXIBLE ROTOR USING ELECTROMAGNETIC ACTUATOR

2015 ◽  
Author(s):  
Edson Hideki Koroishi ◽  
Fabian Andres Lara-Molina ◽  
Valder Steffen Jr
Keyword(s):  
Electromagnetic Actuator ◽  
Modal Control ◽  
Flexible Rotor

A Study on Linear Quadratic Regulator with the Desired Low-Pass Property

2013 ◽  
Vol 133 (12) ◽  
pp. 2167-2175 ◽  
Author(s):  
Katsuhiko Fuwa ◽  
Satoshi Murayama ◽  
Tatsuo Narikiyo
Keyword(s):  
Linear Quadratic Regulator ◽  
Linear Quadratic ◽  
Low Pass

scholarly journals Neural Network Based Contact Force Control Algorithm for Walking Robots

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 287
Author(s):  
Byeongjin Kim ◽  
Soohyun Kim
Keyword(s):  
Neural Network ◽  
Contact Force ◽  
Force Control ◽  
Control Algorithm ◽  
Position Control ◽  
Linear Quadratic Regulator ◽  
Walking Robots ◽  
Test Model ◽  
Linear Quadratic ◽  
Contact Force Control

Walking algorithms using push-off improve moving efficiency and disturbance rejection performance. However, the algorithm based on classical contact force control requires an exact model or a Force/Torque sensor. This paper proposes a novel contact force control algorithm based on neural networks. The proposed model is adapted to a linear quadratic regulator for position control and balance. The results demonstrate that this neural network-based model can accurately generate force and effectively reduce errors without requiring a sensor. The effectiveness of the algorithm is assessed with the realistic test model. Compared to the Jacobian-based calculation, our algorithm significantly improves the accuracy of the force control. One step simulation was used to analyze the robustness of the algorithm. In summary, this walking control algorithm generates a push-off force with precision and enables it to reject disturbance rapidly.

Sign in / Sign up

Export Citation Format

Share Document