The improvement of the so called smart fluids and viscous dampers founded upon them has enabled significantly more effective and convenient shake damping alternatives than ever before. This type of semi-active actuators are already employed in numerous businesses: cars and trucks, automatic washers, bridges, constructing structures to name a few. This is due to the small size and principally to the swift control potential they supply: they can be operated in line with the precise requirements of your shaking system.
This article offers the central theoretical resolution associated with my viscous damper and certain considerations with regard to the assessment of shake. There are other possibilities to regulate the actuator, but I have discovered this particular one simple and beneficial enough. The strategy is not my invention and it applies to any viscous damper. I bow to Jeong-Hoi Koo, whose “Groundhook” algorithm or “velocity-based on-off groundhook control” (On-Off VBG) shown in his dissertation I applied.
Groundhook Rule on Two-Degree-of-Freedom System
The framework in which the control rule is offered is a two-degree-of-freedom mass-spring-damper system. The concept of a groundhook rule is that the mass whose shake is damped, is connected to the ground through a damping element. The semi-active component is the adjustable, viscous damper which is located between the vibrating weights. The control rule is simple: when the upper shaking mass is shifting upwards and the lower weight down, stress is employed to the viscous damper. This induces a pulling force to the structure weight to the stability position of the system.
Groundhook Rule Made Simple on Single-Degree-of-Freedom System
But, as a result of a presupposition or an approximation, this law is usually simplified. In case the speed of the lower weight is believed to be really small and at the same cycle with the shaking weight all the time, the system may be modelled with a single-degree-of-freedom vibration system. If your higher shaking mass is going right up and the lower mass remains put, stress is applied to the viscous damper. That brings about once again a drawing force to the structure weight toward the stability position of the system.
Significance of Comprehending Your Vibration
For you to acquire the most out of the damping potential of a viscous damper, you will need to extensively understand your vibrating system. This means that, you will need to measure the shake of the target correctly to find out the distressing frequencies, their amplitudes and the time instant when the frequencies occur (for instance three seconds from startup).
Only after measuring these, you can come up with how a semi-active viscous damper would solve the situation. Or perhaps you will determine that a classic passive damper is a more feasible solution. Even so, when integrating smart control algorithms on your solution, you should always review the shake system thoroughly.