ACTIVE ISOLATION OF STRUCTURAL VIBRATION ON A MULTIPLE-DEGREE-OF-FREEDOM SYSTEM, PART I: THE DYNAMICS OF THE SYSTEM

1997 ◽  
Vol 207 (1) ◽  
pp. 61-93 ◽  
Author(s):  
P. Gardonio ◽  
S.J. Elliott ◽  
R.J. Pinnington
Keyword(s):  
Degree Of Freedom ◽  
Structural Vibration ◽  
Active Isolation ◽  
System Part

A Study of Control Strategies for the Reduction of Structural Vibration Transmission

1999 ◽  
Vol 121 (4) ◽  
pp. 482-487 ◽  
Author(s):  
P. Gardonio ◽  
S. J. Elliott
Keyword(s):  
Kinetic Energy ◽  
Degrees Of Freedom ◽  
Control Strategies ◽  
Structural Vibration ◽  
Total Power ◽  
Vibration Transmission ◽  
Active Isolation ◽  
Axial Forces ◽  
Common Framework ◽  
Base Structure

A theoretical study of the active control of structural vibration transmission in a multiple isolator system comprising a piece of equipment mounted on a base structure via active mounts is presented. Two types of problem have been studied with a common framework: first, the active isolation of vibration transmission from the equipment to the base structure and, second, the active isolation of vibration transmission from the base structure to the equipment. Four different control strategies using the measured axial velocity or/and axial force underneath or at the top of the mounts have been investigated and compared with the effectiveness of the reference control approaches of minimizing the total power transmitted from the equipment to the flexible base structure or minimizing the total kinetic energy of the suspended rigid equipment when driven by the base structure. For the first type of isolation problem the best control is achieved when a cost function which minimizes the weighted mm of the square values of the axial velocities and axial forces is implemented. For the second isolation problem the best control performance is given by the minimization of an estimate of the kinetic energy of the suspended equipment related to the translational degrees of freedom.

Six Degree of Freedom Active Isolation in Flexible Supporting Structures: Numerical Simulation and Experiment

2003 ◽  
Author(s):  
Yuan Cheng ◽  
Qian Zhou ◽  
Ge-Xue Ren ◽  
Hui Zhang
Keyword(s):  
Stewart Platform ◽  
Degree Of Freedom ◽  
Active Isolation ◽  
Dynamics And Control ◽  
Six Degree Of Freedom ◽  
Multi Body ◽  
And Control ◽  
Flexible Cables ◽  
Base Platform ◽  
Supporting Structures

This paper studies the six degree-of-freedom active isolation of flexible supporting structures using Gough-Stewart platform. The problem arises from a large radio telescope in which the astronomical equipment is mounted on a platform to be stabilized, while the base platform of the mechanism itself is carried by a cable car moving along flexible cables. In this paper, the stabilization problem is equivalent to a dynamics and control problem of multi-body system. A control law of the prediction of the base platform and PD feedback is proposed for the six actuators of the Gough-Stewart platform. Based on numerical results, a model experimental setup has been built up. The control effects are measured with LTD 500 Laser Tracker.

Forced Nonlinear Oscillations of an Autoparametric System—Part 2: Chaotic Responses

1983 ◽  
Vol 50 (3) ◽  
pp. 663-668 ◽  
Author(s):  
H. Hatwal ◽  
A. K. Mallik ◽  
A. Ghosh
Keyword(s):  
Statistical Analysis ◽  
Nonlinear Oscillations ◽  
Degree Of Freedom ◽  
Experimental Results ◽  
Forced Oscillations ◽  
Mean Square ◽  
Chaotic Oscillations ◽  
System Part ◽  
The Mean ◽  
Two Degree Of Freedom

Chaotic oscillations arising in forced oscillations of a two degree-of-freedom autoparametric system are studied. Statistical analysis of the numerically integrated nonperiodic responses is shown to be a meaningful description of the mean square values and the frequency contents of the responses. Some qualitative experimental results are presented to substantiate the necessity of performing the statistical analysis of the responses even though the system and the input are deterministic.

Parametric Stability of a Two-Degree-of-Freedom Machine System: Part I—Equations of Motion and Stability

1987 ◽  
Vol 109 (2) ◽  
pp. 210-215 ◽  
Author(s):  
R. I. Zadoks ◽  
A. Midha
Keyword(s):  
Equations Of Motion ◽  
Monodromy Matrix ◽  
Degree Of Freedom ◽  
Computationally Efficient ◽  
Machine System ◽  
Stable Operating ◽  
System Part ◽  
The Stability ◽  
Nonlinear Equations Of Motion ◽  
Two Degree Of Freedom

An important question facing a designer is whether a certain machine system will have a stable operating condition. To date, the investigations which deal with this question have been scarce. This study treats an elastic two-degree-of-freedom system with position-dependent inertia and external forcing. In Part I, the nonlinear equations of motion are derived and linearized about the system’s steady-state rigid-body response. The stability of the linearized equations is examined using Floquet theory, and a computationally efficient method for approximating the monodromy matrix is presented. A specific example is proposed and the results are presented in Part II of this paper.

Design Development of Rotational Energy Harvesting Vibration Absorber (R-EHTVA)

2018 ◽  
Author(s):  
Francesco Infante ◽  
William Kaal ◽  
Sara Perfetto ◽  
Sven Herold
Keyword(s):  
Energy Harvesting ◽  
Optimization Method ◽  
Degree Of Freedom ◽  
Structural Vibration ◽  
Vibration Absorber ◽  
Design Development ◽  
Dynamic Vibration Absorber ◽  
Rotating System ◽  
Power Sources ◽  
Piezoelectric Energy

This paper proposes a novel idea of a combined piezoelectric energy harvesting and torsional vibration absorber for rotating system. In particular, among possible alternative solutions for durable power sources useable in mechanical components, vibration represents a suitable method for the amount of power required to feed a wireless sensor network. For this purpose energy harvesting from structural vibration has received much attention in the past few years. Suitable vibration can be found in numerous mechanical environments including automotive moving structures, household applications, but also buildings and bridges. Similarly, a dynamic vibration absorber (DVA) is one of the most used devices to mitigate the vibration structures. This device is used to transfer the primary structural vibration to the auxiliary system. Thus, vibration energy is effectively localized in the secondary less sensitive structure and it can be harvested. This paper describes the design process of an energy harvesting tuned vibration absorber for rotating system using piezoelectricity components. Instead of being dissipated as heat, the energy of vibration is converted into electricity. The device proposed is designed to mitigate torsional vibrations as a rotational vibration absorber and to harvest energy as a power source for immediate use. The initial rotational multi degree of freedom system is initially reduced in equivalent single degree of freedom (SDOF) systems. An optimization method is used for evaluating the optimal mechanical parameters of the initial absorber for the SDOF systems defined. The design is modified for the integration of the active patches without detuning the absorber. In order to estimate the real power generated, a complex storage circuit is implemented. A fixed voltage is obtained as output. Through the introduction of a big capacitor, the energy stored is measured at different frequencies. Finally, the simultaneously achievement of the vibration reduction function and the energy harvesting function is evaluated.

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