Claudio Pedrazzi

thanks for your suggestion... But, I found actuators on the web which offer large stroke and require a small power...

Please explain more about your question.

There are some methods:

1- Mechanical mechanisms

2- Hydrulic and penumatic systems

3- Hybrid solutions

.....

Sina,

to me it sounds like you want to make use of some solid state actuator (piezoceramic or magnetostrictive, probably) for some active vibration control system. While the solid state actuators deliver high force, they have a very high mechanical impedance (i.e. are very stiff), so as soon as your mechanical structure has a lower impedance (is less stiff), this will result in a classical impedance mismatch.

What can you do about it? Levers and hydraulics are the classical mechanical solutions, as are any other kind of transmissions. These might somehow be "integrated" / added to your actuators.

Alternatively you might look for different actuators with mechanically matching properties, specific actuator designs (e.g. buckling piezos, effectively embedding the levers within their design) or different mounting points for your actuators with higher mechanical impedance (depends on your problem, for sure).

Another approach for dynamic applications could be some inertial mass design: As force is always applied in between 2 points, you could design a high dynamic impedance just by mounting a mass onto the other end of your actuator - in dynamic operation, such a design will give you a force output.

However, please beware of the necessary masses (depending on frequency), packaging restrictions and also the other mechanical properties of your actuators (e.g. allowable bending forces / shear forces). Such designs are not really straight forward, but do work.