Limiting performance of active vibration compensation in free multi‐degree‐of‐freedom mechanical systems.

A method for identifying the physical parameters of joints in mechanical systems is presented. In the method, a multi-d.o.f. (degree-of-freedom) system is transformed into several single d.o.f. systems using selected eigenvectors. With the result from modal testing, each single d.o.f. system is used to solve for a pair of unknown physical parameters. For complicated cases where the exact eigenvector cannot be obtained, it will be proven that a particular physical parameter has a stationary value in the neighborhood of an eigenvector. Therefore, a good approximation for a joint physical parameter can be obtained by using an approximate eigenvector and the exact value for the joint parameters can be reached by carrying out this process in an iterative way.

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Active Vibration Control of a Three Degree of Freedom Oscillator Using Two Eccentrically Rotating Masses

Lecture Notes in Civil Engineering - Experimental Vibration Analysis for Civil Structures ◽

10.1007/978-3-319-67443-8_52 ◽

2017 ◽

pp. 597-608

Author(s):

R. Terrill ◽

R. Bäumer ◽

U. Starossek

Keyword(s):

Vibration Control ◽

Active Vibration Control ◽

Degree Of Freedom ◽

Active Vibration ◽

Three Degree Of Freedom

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Effects and Prospects of the Vibration Isolation Methods for an Atomic Interference Gravimeter

Sensors ◽

10.3390/s22020583 ◽

2022 ◽

Vol 22 (2) ◽

pp. 583

Author(s):

Wenbin Gong ◽

An Li ◽

Chunfu Huang ◽

Hao Che ◽

Chengxu Feng ◽

...

Keyword(s):

Vibration Isolation ◽

Prospective Development ◽

Passive Vibration Isolation ◽

Isolation Methods ◽

Challenging Environment ◽

Research Findings ◽

Active Vibration ◽

Vibration Compensation ◽

Atomic Interference ◽

Vibration Noise

An atomic interference gravimeter (AIG) is of great value in underwater aided navigation, but one of the constraints on its accuracy is vibration noise. For this reason, technology must be developed for its vibration isolation. Up to now, three methods have mainly been employed to suppress the vibration noise of an AIG, including passive vibration isolation, active vibration isolation and vibration compensation. This paper presents a study on how vibration noise affects the measurement of an AIG, a review of the research findings regarding the reduction of its vibration, and the prospective development of vibration isolation technology for an AIG. Along with the development of small and movable AIGs, vibration isolation technology will be better adapted to the challenging environment and be strongly resistant to disturbance in the future.

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Application of Robust Two Degree-of-Freedom Control Using μ-Synthesis to the Vibrations in Vehicle Engine-Body System

Volume 7B: 17th Biennial Conference on Mechanical Vibration and Noise ◽

10.1115/detc99/vib-8021 ◽

1999 ◽

Author(s):

J. Yang ◽

Y. Suematsu ◽

S. Shimizu ◽

Y. Okumura

Keyword(s):

Degree Of Freedom ◽

Lms Algorithm ◽

Body System ◽

Engine Vibration ◽

Vehicle Engine ◽

Control Scheme ◽

Parameter Variations ◽

Active Vibration ◽

Feedforward Controller ◽

Two Degree Of Freedom

Abstract This paper presents a robust active control for the vehicle engine-body system. The robust two degree-of-freedom (2DOF) controller is formed by combining a feedback (FB) controller with a feedforward (FF) controller. The feedback controller is designed by μ-synthesis to attenuate the effect of engine vibration disturbance by modeling the vehicle engine-body system as a nominal four degree-of-freedom vibration system with the parameter variations and the unmodeled dynamics. Based on filtered-X LMS algorithm, an active vibration controller is used as a feedforward controller to improve control performance further. To demonstrate the effectiveness of the control scheme, we have made some experiments in an experimental device, which is designed to imitate real vehicle engine-body system.

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