Vibration Isolation of a System with One or More Degrees of Freedom

2016 ◽  
pp. 3-36 ◽  
Author(s):  
Igor A. Karnovsky ◽  
Evgeniy Lebed
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation

Theory and Method of Dynamic Modeling for Multilayer Vibration Isolation System

2000 ◽  
Author(s):  
Liao Dao-Xun ◽  
Lu Yong-Zhong ◽  
Huang Xiao-Cheng
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Rigid Bodies ◽  
Design Calculation ◽  
Isolation System ◽  
Dry Land ◽  
Vibration Isolation System ◽  
Six Degrees Of Freedom ◽  
Floating Raft

Abstract The multilayer vibration isolation system has been widely applied to isolate vibration in dynamic devices of ships, high-speed vehicles forging hammer and precise instruments. The paper is based on the coordinate transformation of space general motion for mass blocks (rigid bodies) and Lagrangian equation of multilayer vibration isolation system. It gives a strict mathematical derivation on the differential equation of the motion for the system with six degrees of freedom of relative motion between mass blocks (including base). The equations are different from the same kind of equations in the reference literatures. It can be used in the floating raft of ships in order to isolates vibration and decrease noise, also used in design calculation of the multilayer vibration isolation for dynamic machines and precise instruments on the dry land.

Maglev 6-DOF Stage for Nanopositioning

2003 ◽  
Author(s):  
Wong-Jong Kim ◽  
Shobhit Verma ◽  
Jie Gu
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Mechanical Design ◽  
Wear Particle ◽  
Test Results ◽  
Mechanical Contact ◽  
Position Resolution ◽  
Nanoscale Structures ◽  
Particle Generation ◽  
Six Degrees Of Freedom

This paper presents a novel magnetically levitated (maglev) stage with nanoscale positioning capability in all six degrees of freedom (DOFs). The key aspect of this device is that its single moving part has no mechanical contact with its stationary base, which leads to no mechanical friction and stiction, and no wear particle generation. We present herein the mechanical design, instrumentation, and test results of this maglev stage. Currently it shows position resolution of 4 nm, position noise of 2 nm rms, hundreds-of-micrometer translational travel range, a-few-milliradian rotational travel range, and power consumption less than a fraction of a Watt per axis. This maglev stage can be used in numerous applications such as manufacture of nanoscale structures, assembly and packaging on micro-size parts, vibration isolation for delicate instrumentation, and telepresence microsurgery.

Modeling Research for Active Control of Coupled Vibration between Multiple CNC Milling Machines and Flexible Foundation

2011 ◽  
Vol 105-107 ◽  
pp. 675-679 ◽  
Author(s):  
Fu Dong Ma ◽  
Yao Gang Li ◽  
Qian Lin Peng
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Lagrange Equation ◽  
Real Life ◽  
Traditional Theory ◽  
Cnc Milling ◽  
Isolation System ◽  
Milling Machines ◽  
Flexible Foundation ◽  
Multiple Machines

In real life many agencies are using the flexible foundation as a base of support, such as ship hull or deck, the chassis of car, and machine tools work on stairs. With the traditional theory, the mathematical model between machine and based simplified as single-degree-of-freedom, assuming foundation is a rigid, and many investigate for a single machine, ignoring the dynamic coupling of base and the coupling characteristics between vibrators. This paper build a dynamics model with flexible basis and multiple machines, it’s multi-degrees-of-freedom model. The foundation is flexibled. On this basis builiding a model about multiple machines, flexible foundation and vibration isolation system. This paper resolve to the problem of the machine work on stair, research the system include vibrator, actuators, and flexible foundation. Using Lagrange equation deduce dynamics equation. Express every factor in eqution,deduced the state and space expression.Take prepare for optimal and system simulation.

Gain-Scheduled ℋ∞-Control for Active Vibration Isolation of a Gyroscopic Rotor

2015 ◽  
Author(s):  
Fabian B. Becker ◽  
Martin A. Sehr ◽  
Stephan Rinderknecht
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Linear Time ◽  
Displacement Sensors ◽  
Active Vibration ◽  
And Performance ◽  
Gyroscopic Effects ◽  
Gain Scheduled ◽  
Active Vibration Isolation

This paper deals with active vibration isolation of unbalance-induced oscillations in rotors using gain-scheduled H∞-controller via active bearings. Rotating machines are often exposed to gyroscopic effects, which occur due to bending deformations of rotors and the consequent tilting of rotor disks. The underlying gyroscopic moments are proportional to the rotational speed and couple the rotor’s radial degrees of freedom. Accordingly, linear time-varying models are well suited to describe the system dynamics in dependence on changing rotational speeds. In this paper, we design gain-scheduled H∞-controllers guaranteeing both robust stability and performance within a predefined range of operating speeds. The paper is based on a rotor test rig with two unbalance-induced resonances in its operating range. The rotor has two discs and is supported by one active and one passive bearing. The active support consists of two piezoelectric stack actuators and two collocated piezoelectric load washers. In addition, the rig is equipped with four inductive displacement sensors located at the discs. Closed-loop performance is assessed via isolation of unbalance-induced vibrations using both simulation and experimental data. This contribution is the next step on our path to achieving the long-term objective of combined vibration attenuation and isolation.

scholarly journals Modeling and Control of a Six Degrees of Freedom Maglev Vibration Isolation System

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3608 ◽  
Author(s):  
Qianqian Wu ◽  
Ning Cui ◽  
Sifang Zhao ◽  
Hongbo Zhang ◽  
Bilong Liu
Keyword(s):  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Nonlinear Dynamic Model ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Modeling And Control ◽  
And Control ◽  
Isolation Performance

The environment in space provides favorable conditions for space missions. However, low frequency vibration poses a great challenge to high sensitivity equipment, resulting in performance degradation of sensitive systems. Due to the ever-increasing requirements to protect sensitive payloads, there is a pressing need for micro-vibration suppression. This paper deals with the modeling and control of a maglev vibration isolation system. A high-precision nonlinear dynamic model with six degrees of freedom was derived, which contains the mathematical model of Lorentz actuators and umbilical cables. Regarding the system performance, a double closed-loop control strategy was proposed, and a sliding mode control algorithm was adopted to improve the vibration isolation performance. A simulation program of the system was developed in a MATLAB environment. A vibration isolation performance in the frequency range of 0.01–100 Hz and a tracking performance below 0.01 Hz were obtained. In order to verify the nonlinear dynamic model and the isolation performance, a principle prototype of the maglev isolation system equipped with accelerometers and position sensors was developed for the experiments. By comparing the simulation results and the experiment results, the nonlinear dynamic model of the maglev vibration isolation system was verified and the control strategy of the system was proved to be highly effective.

scholarly journals Realization of a Continuously Phase-Locked Few-Cycle Deep-UV/XUV Pump-Probe Beamline with Attosecond Precision for Ultrafast Spectroscopy

2021 ◽  
Vol 11 (15) ◽  
pp. 6840
Author(s):  
Tsendsuren Khurelbaatar ◽  
Alexander Gliserin ◽  
Je-Hoi Mun ◽  
Jaeuk Heo ◽  
Yunman Lee ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Extreme Ultraviolet ◽  
High Temporal Resolution ◽  
Electron Dynamics ◽  
Nuclear Dynamics ◽  
Pump And Probe ◽  
Active Stabilization ◽  
Continuous Time Delay ◽  
Deep Uv

Chemical and physical processes in molecules can be controlled through the manipulation of quantum interferences between rotational, vibrational, and electronic degrees of freedom. Most of the past efforts have been focused on the control of nuclear dynamics. Even though electronic coherence and its coupling to nuclear degrees of freedom may profoundly affect the outcome of these processes, electron dynamics have received less attention. Proper investigation of electron dynamics in materials demands ultrafast sources in the visible, ultraviolet (UV), and extreme ultraviolet (XUV) spectral region. For this purpose, a few-cycle deep-UV and XUV beamlines have been constructed for studying ultrafast electron dynamics in molecules. To ensure the required high temporal resolution on the attosecond time scale, vibration isolation from environmental mechanical noise and active stabilization have been implemented to achieve attosecond timing control between pump and probe pulses with excellent stability. This is achieved with an actively phase-stabilized double-layer Mach-Zehnder interferometer system capable of continuous time-delay scans over a range of 200 fs with a root-mean-square timing jitter of only 13 as over a few seconds and ~80 as of peak-to-peak drift over several hours.

Study on a 4-DOF multi-dimensional vibration isolation platform based on 4-UPU parallel mechanism

2021 ◽  
Author(s):  
Ying Zhang ◽  
Xiaodong Guo ◽  
Shijia Yu
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Kinematic Model ◽  
Experimental Studies ◽  
Optimization Method ◽  
Response Analysis ◽  
Vibration Model ◽  
Fixed Base ◽  
Physical Prototype

A novel 4-DOF (degrees of freedom) multi-dimensional vibration isolation platform (MDVIP) based on 4-UPU (U denotes universal joint, P denotes prismatic joint) parallel mechanism is put forward for vibration isolation of the sensitive devices. It consists of 4 limbs and each limb has two universal joints and a module of spring damper. The kinematic model and vibration model of the proposed MDVIP are established and analyzed. The main dimensions of the MDVIP and the parameters of the spring damper module are designed by optimization method to meet various design requirements and constraints. Both the virtual prototype and physical prototype of the MDVIP are built to testify the vibration isolation performance. The results of numerical calculation, simulation and experimental studies based on vibration response analysis show that the proposed MDVIP can isolate at least 78% vibration from the fixed base in three axial directions and 64% vibration in the direction around the Z-axis, and thus may attenuate the disturbances to the items on the moving platform to a large extent.

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