Cost Effective Skyhook Control for Vibration Isolation Systems

2005 ◽  
Author(s):  
Xubin Song
Keyword(s):  
Vibration Isolation ◽  
Control Policy ◽  
Cost Effective ◽  
Relative Displacement ◽  
Semiactive Control ◽  
Mass System ◽  
Control Approach ◽  
Car Suspension ◽  
Ride Control ◽  
Isolation Systems

Traditionally a skyhook control, widely applied to vibration control, requires two sensors to measure sprung mass acceleration and relative displacement, respectively. For the implementation, these two measurement signals are converted into velocities and then the damping control signal is decided and sent to controllable HH/SS dampers. In this paper, a one sensor based skyhook control policy is developed. The proposed control policy just needs one measurement signal, sprung mass acceleration, to estimate these two velocities for semiactive control. The new strategy is explained through a typical spring-mass system of a quarter-car model. But the effectiveness of the new control approach for vibration isolation is validated with ride control through simulation study of a 7-DOF full car suspension system with application of magneto-rheological (MR) dampers.

Probability Analysis of Precision Equipment Vibration Isolation System

2013 ◽  
Vol 467 ◽  
pp. 410-415 ◽  
Author(s):  
Vladimir Smirnov ◽  
Vladimir Mondrus
Keyword(s):  
Vibration Isolation ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Relative Displacement ◽  
Probability Analysis ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Isolation Systems ◽  
Gauss Distribution ◽  
Three Dimensional Space

The article deals with probability analysis for a vibration isolation system of sensitive equipment. Vibration isolation system is subjected to external base vibrations due to ambient oscillations (background noise). Considering Gauss distribution for ambient vibrations, we estimate the probability when the relative displacement of isolated mass will still be lower than the vibration criteria. The problem is solved in three-dimensional space, evolved by the system parameters damping and natural frequency. According to this probability distribution, the chance of exceeding vibration criteria for a vibration isolation system is evaluated and different vibration isolation systems are compared.

On Some Problems Associated With Vibration Isolation of Ship Machinery

1977 ◽  
Vol 99 (1) ◽  
pp. 24-30
Author(s):  
J. A. Golinski
Keyword(s):  
Vibration Isolation ◽  
Rotation Speed ◽  
Relative Displacement ◽  
Dynamic Force ◽  
Mass System ◽  
Vibration Isolators ◽  
A Value ◽  
Dynamic Forces ◽  
Single Mass ◽  
Inertia Forces

Vibration isolators of machines installed on ships are subject to both dynamic forces involved with the working of these machines and inertia forces resulting from the rolling of the ship. In order to illustrate this better, a solution of the vibration equation of a single mass system has been analyzed, the system being excited simultaneously by a dynamic force and a motion of foundation. It has been found that the larger the ratio of rotation speed is to natural frequency of vibration, the larger is the relative displacement of a machine mounted on vibration isolators. To obtain as small as possible a value of this ratio it might be necessary to use “hard” isolators, but such a solution is not one of the best, because forces transmitted to the foundation would then be larger than the dynamic forces causing the vibration of this machine. Thus the author recommends employing “soft” isolators, on condition, however, that the frequency ratio mentioned previously be chosen such that the elastic deformation of the isolators be within allowable limits.

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.

Structural analysis of the trajectories of random processes formed in non-linear vibration isolation systems

2021 ◽  
Author(s):  
A.S. Gusev ◽  
L.V. Zinchenko ◽  
S.A. Starodubtseva
Keyword(s):  
Structural Analysis ◽  
Vibration Isolation ◽  
Fundamental Principle ◽  
Statistical Dependence ◽  
Absolute Maximum ◽  
Time Interval ◽  
Apparent Lack ◽  
The Road ◽  
Isolation Systems ◽  
Non Gaussian

When designing technical structures, the safety of their elements is a fundamental principle. This highlights the significance of the proposed solution to the structural analysis of the trajectories of non-Gaussian stationary processes. The solution aims to acquire source data for calculating the stress-strength reliability of structural elements operating under random loads. We analyze an approach that makes it possible to account for the statistical dependence between processes and their derivatives, despite the apparent lack of correlation between them. The considered approach can be utilized in the design of vibration protection of transport vehicles to calculate the probability of a shock absorber breakdown, the probability of loss of the road-wheel contact, etc. The operation reliability of such systems is defined as the probability that the absolute maximum of the process does not exceed the specified standard level during a certain time interval. The article presents the reliability calculation using structural analysis on the example of a one-dimensional stochastic system.

A Pneumatic On-Off Vehicle Suspension System

1977 ◽  
Vol 99 (2) ◽  
pp. 130-136 ◽  
Author(s):  
D. L. Klinger ◽  
A. J. Calzado
Keyword(s):  
Vibration Isolation ◽  
Relative Displacement ◽  
Disturbance Attenuation ◽  
Vehicle Suspension ◽  
System Complexity ◽  
Pressure Transducers ◽  
Control Signals ◽  
Pneumatic Suspension ◽  
Simulation Results ◽  
Vehicle Suspension System

An active, nonlinear, pneumatic suspension applicable to passenger railcars is described. Standard on-off valves modulate pressure differences between dual opposing airbags to attenuate vibration and create guidance forces. Improved vibration isolation over that of conventional passive suspensions is achieved at low power levels. Guidance forces are provided with small suspension travel using short bursts of compressed air taken from vehicle supply reservoirs. Acceleration, relative displacement, and pressure transducers provide the control signals required for stabilization, feedforward guidance commands, and disturbance attenuation. Simulation results indicate that performance comparable to hydraulic servosystems can be attained with substantially reduced system complexity and power requirements.

Design of a Miniaturized Pneumatic Vibration Isolator With High-Static-Low-Dynamic Stiffness

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Yuhu Shan ◽  
Wenjiang Wu ◽  
Xuedong Chen
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Structure Design ◽  
Negative Stiffness ◽  
Vibration Isolator ◽  
Load Bearing Capacity ◽  
Compact Structure ◽  
Chamber Volume ◽  
Isolation Systems ◽  
Magnetic Rings

In the ultraprecision vibration isolation systems, it is desirable for the isolator to have a larger load bearing capacity and a broader isolation bandwidth simultaneously. Generally, pneumatic spring can bear large load and achieve relatively low natural frequency by enlarging its chamber volume. However, the oversized isolator is inconvenient to use and might cause instability. To reduce the size, a miniaturized pneumatic vibration isolator (MPVI) with high-static-low-dynamic stiffness (HSLDS) is developed in this paper. The volume of proposed isolator is minimized by a compact structure design that combines two magnetic rings in parallel with the pneumatic spring. The two magnetic rings are arranged in the repulsive configuration and can be mounted into the chamber to provide the negative stiffness. Then dynamic model of the developed MPVI is built and the isolation performances are analyzed. Finally, experiments on the isolator with and without the magnetic rings are conducted. The final experimental results are consistent with the dynamical model and verify the effectiveness of the developed vibration isolator.

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