Active Vibration Isolation Platform Research Articles

Design of active vibration isolation system for satellite optical load based on Stewart platform

According to the requirements of hyperstatic environment of a satellite optical load during in orbit operation, the Stewart active vibration isolation platform was designed, and its dynamic equation was established by Newton Euler method. The virtual prototype model was established in ADAMS, and the accuracy of the model was verified by comparing the numerical solution and simulation solution of the modal frequency of the platform; On this basis, the dynamic model is decoupled into six SISO systems, and the optimal controller is designed for each subsystem. Finally, the whole system is simulated by ADAMS/MATLAB, and the displacement response curves of the load before and after control are obtained. The simulation results show that the Stewart active vibration isolation platform can effectively suppress the vibration.

Design and Mechanical Performance Analysis of Vibration Reduction and Isolation Platform

Vibration reduction and isolation platform is a device that can effectively reduce or isolate vibration in space environment. It is widely used in precision equipment fields such as mechanical structure, precision machining, optical instruments. A three-stage mechanical active vibration reduction and isolation platform is designed. The static analysis is carried out using professional software. The research results show that when 3000N concentrated load is applied on the working platform, the maximum deformation is 0.0073mm, the maximum stress is 2.82MPa. And when 4000N asymmetric load is applied, the maximum deformation is 0.048mm, the maximum stress is 200MPa. The modal analysis results show that the first frequency is 40Hz and the sixth frequency is 180Hz. The product has certain engineering application value.

Fuzzy Control of Floating Raft Active Vibration Isolation System under Narrowband Interference

The harmonic signal generated by power equipment on naval vessels is a typical narrowband interference, which seriously affects the stealth performance of naval vessels. The float raft active vibration isolation system is characterized by strong adaptability and good controllability, which can effectively isolate low-frequency interference. For the active vibration isolation system, the control strategy is one of the core, and the precise mathematical model is difficult to be established. The fuzzy control does not rely on the precise mathematical model of the controlled system, which cannot only provide an intelligent path for the active control of the complex floating raft system, but also effectively suppresses the narrowband interference caused by naval vessels' power equipment. Therefore, depending on the existing float raft active vibration isolation platform, this paper outlines a design for a two-input/single-output optimized fuzzy control system based on vibration acceleration, variation of vibration acceleration and control voltage. In an optimized fuzzy control system, an algorithm of quantum behavior particle swarm optimization algorithm (QPSO) is proposed to optimize quantization factor and scale factor because quantization factor and scale factor are set subjectively with strong subjectivity and blindness, and the stability of the control system is roughly verified. Therefore, simulations and experiments are carried out to test and verify the performance of control system designs outlined in this paper. Through comparative analysis, it shows that the floating raft active vibration isolation system with a fuzzy control system based on the QPSO algorithm has a favorable effect on low-frequency narrowband interference.

A review of spectral analysis for low-frequency transient vibrations

The precision tools equipped with active vibration isolation platform in high-tech facilities are sensitive to low-frequency vibration. Currently, there are neither standards nor rules to select the time period of vibration data for conducting the spectral analysis of low-frequency vibration, and none of the analyses can be used to compare and discuss the differences of spectral amplitude generated by the selection of different time periods. Therefore, to estimate the amplitude of low-frequency vibration, the spectral analysis at low-frequency range is crucial. This paper is to elaborate the spectral analysis procedures on various band widths by using zero-padding on the vibration signal in low-frequency band. The mechanism not only facilitates to obtain more reliable result but also to lay a common base for comparison from different user. Finally, the in situ measurement data, including high-speed train-induced low-frequency vibration, are used to exemplify the length of time period affects the results of spectral analysis, either on narrowband or one-third octave band analysis.

Active vibration isolation platform on base of magnetorheological elastomers

The article describes the active vibration isolation platform on base of magnetorheological (MR) elastomers. An active damper based on the MR elastomers can be used as an actuator of micro- or nanopositioning for a vibroinsulated object. The MR elastomers give such advantages for active control of vibration as large range of displacements (up to 1mm), more efficient absorption of the vibration energy, possibility of active control of amplitude-frequency characteristics and positioning with millisecond response speed and nanometer running accuracy. The article presents the results of experimental studies of the most important active damper parameters. Those are starting current, transient time for stepping, transmission coefficient of the vibration displacement amplitude.

Parametric Design and Multiobjective Optimization of Maglev Actuators for Active Vibration Isolation System

The microvibration has a serious impact on science experiments on the space station and on image quality of high resolution satellites. As an important component of the active vibration isolation platform, the maglev actuator has a large stroke and exhibits excellent isolating performance benefiting from its noncontact characteristic. A maglev actuator with good linearity was designed in this paper. Fundamental features of the maglev actuator were obtained by finite element simulation. In order to minimize the coil weight and the heat dissipation of the maglev actuator, parametric design was carried out and multiobjective optimization based on the genetic algorithm was adopted. The optimized actuator has better mechanical properties than the initial one. Active vibration isolation platforms for different-scale payload were designed by changing the arrangement of the maglev actuators. The prototype to isolate vibration for small-scale payload was manufactured and the experiments for verifying the characteristics of the actuators were set up. The linearity of the actuator and the mechanical dynamic response of the vibration isolation platform were obtained. The experimental results highlight the effectiveness of the proposed design.

Dynamic Characteristics of Integrated Active and Passive Whole-Spacecraft Vibration Isolation Platform Based on Non-Probabilistic Reliability

Dynamic Characteristics of Integrated Active and Passive Whole-Spacecraft Vibration Isolation Platform Based on Non-Probabilistic Reliability

Optimal Design and Simulation of Active Vibration Isolation Platform Based on Fuzzy Control

In order to improve the isolation effect of ultra-precision vibration isolation platform, an approach of advancing structural parameters optimization for the system based on fuzzy control is presented. This paper created a platform parametric model In ADAMS / view; completed the structural optimization under circumstances of taking the acceleration of vibration isolation platform, the system dynamic deflection and the dynamic displacement of the base as performance objective function; and applied the method of co-simulation using ADAMS and MATLAB under fuzzy control. The simulation results show that the active vibration isolation system optimized by ADAMS could effectively enhance the effect of active vibration isolation platform; the method of co-simulation provided a new way for dynamics studies of vibration isolation system.

Control Relevant Blind Identification of Disturbances With Application to a Multivariable Active Vibration Isolation Platform

This paper deals with the identification of root causes of disturbances in multivariable systems. It is shown that this boils down to a blind identification problem that can be solved, under additional assumptions, within certain indeterminacies. Using the results from identification, it is illustrated how sources can be physically interpreted and the location of the sources can be recovered. Also, a design tool is developed to select multivariable feedback controller candidates. The practical feasibility is demonstrated on an industrial multivariable controlled active vibration isolation platform.

A Nd:YAG Laser with short-term frequency stability at the Hertz-level

We report on the frequency stabilisation of a Nd:YAG laser at 946 nm to the Hertz-level. The laser will be used for ultra-high resolution spectroscopy of the 5 s 2 1 S 0−5 s5p 3 P 0 transition in In + and will ultimately serve as a local oscillator of an optical frequency standard based on a single trapped indium ion. To resolve the extremely narrow 1 S 0− 3 P 0 resonance (natural linewidth 0.82 Hz) at 237 nm, the frequency-quadrupled Nd:YAG laser radiation has to be frequency stable at the Hertz-scale for measurement times up to several tens of seconds. We obtain the frequency stability of the laser by locking it onto an external reference cavity of high finesse, placed on an active vibration isolation platform.