keskiviikko 28. syyskuuta 2011

Viscous Damper Regulation



The advancement of the so called intelligent fluids and viscous dampers based upon them has enabled much more effective and versatile shake damping potentialities than previously. Such semi-active attenuators are already utilized in many businesses: cars and trucks, washing machines, bridges, building structures to name a few. This is resulting from the small size and especially to the speedy control capability they present: they might be mastered according to the exact requires of your vibrating system.

This short article provides the primary theoretical strategy behind my viscous damper and a few points concerning the examination of vibration. There are various other possibilities to regulate the actuator, but I have found this particular one easy and practical enough. The method is not my design and it is valid for any kind of viscous damper. I give credit to Jeong-Hoi Koo, whose “Groundhook” algorithm or “velocity-based on-off groundhook control” (On-Off VBG) introduced in his dissertation I applied.

Groundhook Law on Two-Degree-of-Freedom System

The framework where the control law is offered is a two-degree-of-freedom mass-spring-damper system.
The concept of a groundhook rule is that the weight whose shake is attenuated, is connected to the ground with a damping element. The semi-active component is the adjustable, viscous damper that is placed in between the shaking masses.
The control law is straightforward: when higher shaking weight is shifting up and the lower mass down, stress is applied to the viscous damper. This brings about a drawing force to the structure weight in direction of the balance situation of the system.

Groundhook Law Made easy on Single-Degree-of-Freedom System

But, as a result of a presumption or an approximation, this rule might be made easy. In case the speed of the lower weight is believed to be really small and at the same cycle with the shaking weight continuously, the process might be modelled by using a single-degree-of-freedom vibration system. If the higher shaking weight is going upwards and the lower mass stays still, tension is employed to the viscous damper. That causes once more a pulling force to the structure mass towards the stability situation of the system.

Significance of Recognizing Your Vibration

To be able to grab essentially the most out of the attenuation potential of a viscous damper, you have to thoroughly comprehend your moving system. To put it differently, you need to find out the vibrations of the object accurately to find out the unsettling wavelengths, their magnitudes and the time prompt when the frequencies take place (for instance three seconds from startup).

Solely once measuring these, you'll be able to start designing how a semi-active viscous damper would clear up the challenge. Or perhaps you will uncover that a conventional passive damper is a more feasible solution. Nevertheless, when integrating clever control algorithms on your solution, you have to definitely analyze the vibration system to the bottom.

If you would wish to discover more about viscous dampers, have a look at www.magnetorheologicaldamper.com. Magnetorheological Damper Laboratory is specialized in explain the aspects of controlling a viscous damper.