scholarly journals Universal technique of elimination of power parametric excitation in general mechanical systems

2018 ◽  
Vol 1050 ◽  
pp. 012008
Author(s):  
P D Balakin ◽  
I P Zgonnik
Keyword(s):  
Parametric Excitation ◽  
Mechanical Systems

Frequency Sweeping With Concurrent Parametric Amplification

2008 ◽  
Author(s):  
Nicholas J. Miller ◽  
Steven W. Shaw
Keyword(s):  
Quality Factor ◽  
Parametric Excitation ◽  
Mechanical Systems ◽  
Parametric Amplification ◽  
Stability Conditions ◽  
Mass Sensor ◽  
Modal Interactions ◽  
Numerical Example ◽  
Mems Mass Sensor ◽  
Frequency Sweeping

In this paper we explore parametric amplification of multidegree of freedom mechanical systems. We consider frequency conditions for modal interactions and determine stability conditions for three important cases. We develop conditions under which it is possible to sweep with direct and parametric excitation to produce a sweep response with amplified effective quality factor of resonances encountered during the sweep. With this technique it is possible to improve the measurement of resonance locations in swept devices, such as those that operate on resonance shifting. A numerical example motivated by a MEMS mass sensor is given in support of the analysis.

scholarly journals Parametric Excitation Walking of a Biped Robot Using Counter Weight(Mechanical Systems)

2010 ◽  
Vol 76 (768) ◽  
pp. 2117-2126 ◽  
Author(s):  
Takeshi HAYASHI ◽  
Fumihiko ASANO ◽  
Kazuaki KANEKO ◽  
Zhi-Wei LUO ◽  
Atsuo KATO
Keyword(s):  
Parametric Excitation ◽  
Mechanical Systems ◽  
Biped Robot

Frequency Sweeping With Concurrent Parametric Amplification

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Nicholas J. Miller ◽  
Steven W. Shaw
Keyword(s):  
Parametric Excitation ◽  
Mechanical Systems ◽  
Parametric Amplification ◽  
Stability Conditions ◽  
Mass Sensor ◽  
Frequency Range ◽  
Quality Factors ◽  
Modal Interactions ◽  
Electromechanical Systems ◽  
Frequency Sweeping

In this paper, we explore parametric amplification of multiple resonances in multidegree-of-freedom mechanical systems, and the use of frequency sweeping with a parametric pump to amplify several adjacent resonance peaks. We develop conditions under which it is possible to sweep with direct and parametric excitation to produce a sweep response with amplified effective quality factors for all resonances over a given frequency range. We determine gain and stability conditions and include analysis for potential problematic modal interactions. This technique makes it possible to improve the measurements of resonance locations in devices, for example, sensors that rely on tracking shifts in resonance peaks. The results are demonstrated on a model for a multi-analyte micro-electromechanical systems mass sensor.

Experimental studies on damping by parametric excitation using electromagnets

2012 ◽  
Vol 226 (8) ◽  
pp. 2015-2027 ◽  
Author(s):  
F Dohnal
Keyword(s):  
Parametric Excitation ◽  
Vibration Suppression ◽  
Experimental Studies ◽  
Mechanical Systems ◽  
Variable Stiffness ◽  
Excitation Amplitude ◽  
Open Loop ◽  
Basic Step ◽  
Mass System ◽  
Loop Control

Transient vibrations in mechanical systems are a common problem in engineering. Several theoretical studies have shown analytically and numerically that a vibrating system can be stabilised or its vibrations can be reduced when excited close to a specific parametric combination resonance frequency. At this operation, the transient vibrations are effectively damped by parametric excitation. The basic step in exploiting this method is its experimental implementation in mechanical systems. In this review, recent experiments are discussed for a simple chain mass system, a continuous cantilever and a flexible rotor system. The parametric excitation is realised by electromagnetic variable-stiffness actuators driven by a periodic open-loop control. It is demonstrated experimentally that a parametrically excited structure can exhibit enhanced damping properties. A certain level of the excitation amplitude has to be exceeded to achieve the damping effect in which the existing damping in the system is artificially amplified. Upon exceeding this value, the additional artificial damping provided to the system is significant and most effective for vibration suppression of the lower vibration modes.

Applications of the Theory of Impulsive Parametric Excitation and New Treatments of General Parametric Excitation Problems

1973 ◽  
Vol 40 (1) ◽  
pp. 78-86 ◽  
Author(s):  
C. S. Hsu ◽  
W.-H. Cheng
Keyword(s):  
Parametric Excitation ◽  
Stability Theory ◽  
Mechanical Systems ◽  
General Nature ◽  
Periodic Systems ◽  
Stability Conditions ◽  
Approximate Methods ◽  
Step Functions ◽  
The Stability ◽  
New Treatments

In this paper the stability theory of impulsive parametric excitation developed in [1] is first applied to three mechanical systems. Explicit and exact stability conditions are easily found and some typical stability charts are presented. Also presented in the paper is the use of this theory and a parallel theory involving step functions as approximate methods for treating periodic parametric excitations of more general nature. Exploratory studies along this line have led us to believe that these approximate methods have promise to be very powerful and practical tools for dealing with the stability of general high-order periodic systems.

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