Transmissibilities of Two-Degree-of-Freedom Systems for Semi-Active Vibration Control

Aerospace ◽  
2006 ◽  
Author(s):  
H. F. Lam ◽  
W. H. Liao
Keyword(s):  
Control Systems ◽  
Active Control ◽  
Transfer Functions ◽  
Active Vibration Control ◽  
Degree Of Freedom ◽  
Reference Systems ◽  
Active Systems ◽  
Active Vibration ◽  
Equivalent Systems ◽  
Two Degree Of Freedom

Transmissibilities for two-degree-of-freedom (2DoF) passive systems have been extensively investigated in the past. However, for semi-active control systems, the transmissibilities are rarely analyzed. The expressions of non-dimensional transmissibilities for the semi-active control systems are not found. There are no closed-form transfer functions for general semi-active control systems. The control algorithms for semi-active systems need to be specified first. Therefore, three reference systems (skyhook, groundhook, and their hybrid) are proposed. These equivalent systems are the references for the semi-active control systems to achieve. In this paper, the 2DoF skyhook, groundhook and hybrid systems for semi-active control are studied. The displacement and acceleration transmissibilities of those three reference systems are formulated and analyzed. Their transmissibilities are also compared with the passive system. Each of reference systems is classified as Ideal and Non-Ideal systems. The differences between the Ideal and Non-Ideal systems are also discussed. The optimal systems and their corresponding parameters are identified.

Frequency Shaped Semi-Active Control for Magnetorheological Fluid-Based Vibration Control Systems

2013 ◽  
Author(s):  
Young-Tai Choi ◽  
Norman M. Wereley ◽  
Gregory J. Hiemenz
Keyword(s):  
Vibration Control ◽  
Control Systems ◽  
Active Control ◽  
Control Algorithm ◽  
Active Vibration Control ◽  
Control Algorithms ◽  
Model Parameters ◽  
Mr Fluid ◽  
Control Current ◽  
Active Vibration

Novel semi-active vibration controllers are developed in this study for magnetorheological (MR) fluid-based vibration control systems, including: (1) a band-pass frequency shaped semi-active control algorithm, (2) a narrow-band frequency shaped semi-active control algorithm. These semi-active vibration control algorithms designed without resorting to the implementation of an active vibration control algorithms upon which is superposed the energy dissipation constraint. These new Frequency Shaped Semi-active Control (FSSC) algorithms require neither an accurate damper (or actuator) model, nor system identification of damper model parameters for determining control current input. In the design procedure for the FSSC algorithms, the semi-active MR damper is not treated as an active force producing actuator, but rather is treated in the design process as a semi-active dissipative device. The control signal from the FSSC algorithms is a control current, and not a control force as is typically done for active controllers. In this study, two FSSC algorithms are formulated and performance of each is assessed via simulation. Performance of the FSSC vibration controllers is evaluated using a single-degree-of-freedom (DOF) MR fluid-based engine mount system. To better understand the control characteristics and advantages of the two FSSC algorithms, the vibration mitigation performance of a semi-active skyhook control algorithm, which is the classical semi-active controller used in base excitation problems, is compared to the two FSSC algorithms.

A Design Method for Two-Degree-of-Freedom Simple Multi-Period Repetitive Control Systems

2010 ◽  
Vol 36 ◽  
pp. 243-252 ◽  
Author(s):  
Yoshinori Ando ◽  
Tatsuya Sakanushi ◽  
Kou Yamada ◽  
Iwanori Murakami ◽  
Takaaki Hagiwara ◽  
...  
Keyword(s):  
Control System ◽  
Control Systems ◽  
Transfer Functions ◽  
Design Method ◽  
Output Characteristic ◽  
Degree Of Freedom ◽  
Disturbance Attenuation ◽  
Input Output ◽  
Attenuation Characteristic ◽  
Two Degree Of Freedom

The multi-period repetitive (MPR) control system is a type of servomechanism for periodic reference inputs. Using MPR controllers, transfer functions from the reference input to the output and from the disturbance to the output of the MPR control system have infinite numbers of poles. To specify the input-output characteristic and the disturbance attenuation characteristic easily, Yamada and Takenaga proposed MPR control systems, named simple multi-period repetitive (simple MPR) control systems, where these transfer functions have finite numbers of poles. In addition, Yamada and Takenaga clarified the parameterization of all stabilizing simple MPR controllers. However, using the simple MPR repetitive controller by Yamada and Takenaga, we cannot specify the input-output characteristic and the disturbance attenuation characteristic separately. From the practical point of view, it is desirable to specify the input-output characteristic and the disturbance attenuation characteristic separately. The purpose of this paper is to propose the parameterization of all stabilizing two-degree-of-freedom (TDOF) simple MPR controllers that can specify the input-output characteristic and the disturbance attenuation characteristic separately.

scholarly journals Two-Degree-of-Freedom Active Vibration Control of a Prototyped “Smart” Rotor

2011 ◽  
Vol 19 (2) ◽  
pp. 284-296 ◽  
Author(s):  
Jan-Willem van Wingerden ◽  
Anton Hulskamp ◽  
Thanasis Barlas ◽  
Ivo Houtzager ◽  
Harald Bersee ◽  
...  
Keyword(s):  
Vibration Control ◽  
Active Vibration Control ◽  
Degree Of Freedom ◽  
Active Vibration ◽  
Two Degree Of Freedom

scholarly journals Modified Independent Modal Space Control Method for Active Control of Flexible Systems

1989 ◽  
Vol 203 (2) ◽  
pp. 103-112 ◽  
Author(s):  
A Baz ◽  
S Poh ◽  
P Studer
Keyword(s):  
Control Systems ◽  
Active Control ◽  
Control Method ◽  
Active Vibration Control ◽  
Flexible Structures ◽  
Optimal Placement ◽  
Flexible Systems ◽  
Time Sharing ◽  
Active Vibration ◽  
Modal Space

A modified independent modal space control (MIMSC) method is developed for designing active vibration control systems for large flexible structures. The method accounts for the interaction between the controlled and residual modes. It also incorporates optimal placement procedures for selecting the optimal locations of the actuators in the structure in order to minimize the structural vibrations as well as the actuation effort. The MIMSC method relies on an important feature which is based on ‘time sharing’ of a small number of actuators, in the modal space, to control effectively a large number of modes. Numerical examples are presented to illustrate the application of the method to generic flexible systems. The obtained results suggest the potential of the devised method in designing efficient active control systems for large flexible structures.

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