Robust QFT Control of a Piezo-Based Vibration Isolation System With Consideration of Hysteresis Effect

Volume 1 ◽  
2004 ◽  
Author(s):  
Meng-Shiun Tsai ◽  
Feng-Ching Chiang ◽  
Yan-Shuo Sun ◽  
Jen-Hua Wu
Keyword(s):  
Disturbance Rejection ◽  
Vibration Isolation ◽  
Closed Loop ◽  
Approximate Model ◽  
Hysteresis Effect ◽  
Hysteresis Model ◽  
Robust Performance ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Three Degree Of Freedom

In this paper, we investigate a three-degree-of-freedom (X-Y-Z) piezo-based vibration isolation platform. The hysteresis effect together with system uncertainties are represented by an approximate model. The approximate model consists of a variable gain and variable time-delay which are the functions of the input magnitude and frequency. Experiments are performed to identify the parameters of the proposed approximate model. To achieve robust performance of the isolation system with consideration of the hysteresis effect, quantitative feedback theory (QFT) controller is proposed. The hysteresis model is naturally built into the template of plant. It is shown from closed loop experiments that the designed controller can achieve high disturbance rejection within the bandwidth of 10–60Hz for the MIMO vibration isolation system.

Passage Through Resonance in a Vibration Isolation System (Effects of Rate of Increasing the Voltage Applied to D.C. Motor)

2007 ◽  
Author(s):  
Tomohiko Tange ◽  
Ryo Kawana ◽  
Tetsuro Tokoyoda ◽  
Masatsugu Yoshizawa ◽  
Toshihiko Sugiura
Keyword(s):  
Rigid Body ◽  
Internal Resonance ◽  
Vibration Isolation ◽  
Transient Behavior ◽  
Degree Of Freedom ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Rotational Vibration ◽  
Three Degree Of Freedom ◽  
Driving Torque

This paper deals with transient nonlinear vibration of a rigid body suspended on a foundation by elastic springs and constrained in a plane. In such a three degree-of-freedom vibration isolation system, we assume that ‘2-1-1’ internal resonance exists between the vertical and horizontal vibrations of the rigid body and the rotational vibration about its center of gravity. Our main purpose is to examine theoretically the transient behavior passing through resonance under the condition that the D.C. motor directly drives the unbalanced rotor. Numerical simulation was carried out to clarify effects of rate of increasing V(t) on the peak amplitude of the vibration of the rigid body and on the driving torque of the D.C. motor. Moreover, experiment was conducted with a physical model of a three degree-of-freedom vibration isolation system, and the transient behavior passing through resonance was observed and compared with theoretical results in a typical case with internal resonance.

Passage Through Resonance in a Three Degree-of-Freedom Vibration Isolation System

2005 ◽  
Author(s):  
Ryo Kawana ◽  
Tetsuro Tokoyoda ◽  
Kazushige Sato ◽  
Masatsugu Yoshizawa ◽  
Toshihiko Sugiura
Keyword(s):  
Rigid Body ◽  
Vibration Isolation ◽  
Transient Behavior ◽  
Degree Of Freedom ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Unbalanced Rotor ◽  
Rotational Vibration ◽  
Three Degree Of Freedom ◽  
Theoretical Results

This paper deals with transient nonlinear vibration of a rigid body suspended on a foundation by elastic springs and constrained in a plane. In such a three degree-of-freedom vibration isolation system, we assume that ‘2-1-1’ internal resonance exists between the vertical and horizontal vibrations of the rigid body and the rotational vibration about its center of gravity. Next, the vibration of the rigid body is captured into or passes through resonance when the rotation speed of an unbalanced rotor equipped with the rigid body is increased. We theoretically examined the transient behavior of passage through resonance under the condition that a DC motor directly drives the unbalanced rotor with a limited electric current. Moreover, the experiment was conducted with a physical model of such a system, and transient oscillations through resonance were observed and compared with theoretical results in a few cases of limited currents.

Line spectra chaotification of the nonlinear vibration isolation system on the flexible foundation based on the open-plus-nonlinear-closed-loop method

2020 ◽  
pp. 107754632093376
Author(s):  
Kai Chai ◽  
Shuang Li ◽  
Jun J Lou ◽  
Xiang Yu ◽  
Yong S Liu ◽  
...  
Keyword(s):  
Nonlinear Vibration ◽  
Working Conditions ◽  
Vibration Isolation ◽  
Closed Loop ◽  
Initial Conditions ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Loop Control ◽  
Loop Method ◽  
Flexible Foundation

Line spectra chaotification is a principal method to weaken or eliminate the line spectra feature of submarines. However, this method is difficult to obtain chaos under the variable working conditions and small amplitudes. Furthermore, there are multistable attractors in the nonlinear vibration isolation system simultaneously. So, the quality of chaos highly depends on initial conditions and systematic parameters. In this study, the attractor entrainment control and line spectra chaotification of a nonlinear vibration isolation system on the flexible foundation have been studied by using the open-plus-nonlinear-closed-loop method. First, the dynamic equation of the nonlinear vibration isolation system on the flexible foundation was formulated, and its exhaustive bifurcation characteristics were analyzed. The regulations of global characteristics and coexistent attractors were found out. Second, the entrainments between the different attractors were carried out under the open-plus-nonlinear-closed-loop control, which can ensure the system always works in the lowest line spectra intensity and the best overall vibration isolation performance. Finally, an open-plus-nonlinear-closed-loop coupling method was used to achieve generalized chaotic synchronization between the driving system and the response system, which effectively obtained sustainable chaos even under variable working conditions and small amplitudes. Simulation results validate the feasibility and validity of the open-plus-nonlinear-closed-loop method, which achieves the dual goals of effective vibration isolation in the low frequency range and line spectra chaotification under variable working conditions.

Design and analysis of a vibration isolation system with cam–roller–spring–rod mechanism

2021 ◽  
pp. 107754632110005
Author(s):  
Yonglei Zhang ◽  
Guo Wei ◽  
Hao Wen ◽  
Dongping Jin ◽  
Haiyan Hu
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Experimental Studies ◽  
Excitation Amplitude ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Stiffness Characteristic ◽  
Negative Stiffness Mechanism ◽  
Isolation Systems ◽  
Vibration Isolation Performance

The vibration isolation system using a pair of oblique springs or a spring-rod mechanism as a negative stiffness mechanism exhibits a high-static low-dynamic stiffness characteristic and a nonlinear jump phenomenon when the system damping is light and the excitation amplitude is large. It is possible to remove the jump via adjusting the end trajectories of the above springs or rods. To realize this idea, the article presents a vibration isolation system with a cam–roller–spring–rod mechanism and gives the detailed numerical and experimental studies on the effects of the above mechanism on the vibration isolation performance. The comparative studies demonstrate that the vibration isolation system proposed works well and outperforms some other vibration isolation systems.

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