Page 318 - Mechanics of Microelectromechanical Systems

5. Static response of MEMS 305

Figure 5.40 Reduced quarter-model of sagittal microdevice with straight flexure hinge
under actuation and load

The procedure of finding the output displacement is similar to the ones
applied to find the output stiffness and the displacement amplification for this
microdevice. In essence, and without repeating the calculus that has been
already detailed previously, the output displacement that is produced under
the combined action of the input force F and the resistive force is:

It is important to determine the maximum value of the resistive force
which will bloc the motion at the output port of a sagittal microdevice and
which is known as the bloc force. By taking in Eq. (5.114), produces
the following equation of the bloc force:

The displacement amplification microdevices can be combined in
various ways in order to tune certain stiffness properties or to augment the
absolute output levels that cannot be reached by using a single unit.

Figure 5.41 Arrangement for displacement amplification enhancement