The Art and Signs of a Few Good Mechanical Designs in MEMS
39
Fig. 10 A two-segment version of the design in Fig. 9 to make a longer beam stay flat. Undeformed
and deformed configurations are shown
Fig. 11 A diffracting cell
using an array of beams used
in a polychromator
should contemplate a similar design in Sect. 7 wherein it is wrapped around a circle
for even more amazing functionality.
6 Optimality of a Displacement-Amplifying Compliant
Mechanism
The design discussed in the preceding section was most likely intuitively conceived.
It was a remarkable example of human ingenuity. Those who use optimization techniques or those who develop them tend to think that algorithms too can give rise to
clever designs. Designs generated by optimization algorithms can be counterintuitive. They are often beyond the grasp of human creativity. Thus, designs obtained
using optimization algorithms are sometimes superior. Additionally, they are also
optimal for the conditions set in formulating the optimization problem unlike intuitive designs that could be further tweaked and optimized. We illustrate this using an
amplifying mechanism.
A lever, immortalized by Aristotle, comes to mind when we think of a mechanical
amplifier. When a pin joint (i.e., a revolute joint) is not practically viable (as is the
case with microfabrication), a simple lever is not a preferred choice. A flexure that
replaces a pin joint is also not a good choice because of high stress and limited
range of rotation. Furthermore, for large amplification ratio of output and input
39
Fig. 10 A two-segment version of the design in Fig. 9 to make a longer beam stay flat. Undeformed
and deformed configurations are shown
Fig. 11 A diffracting cell
using an array of beams used
in a polychromator
should contemplate a similar design in Sect. 7 wherein it is wrapped around a circle
for even more amazing functionality.
6 Optimality of a Displacement-Amplifying Compliant
Mechanism
The design discussed in the preceding section was most likely intuitively conceived.
It was a remarkable example of human ingenuity. Those who use optimization techniques or those who develop them tend to think that algorithms too can give rise to
clever designs. Designs generated by optimization algorithms can be counterintuitive. They are often beyond the grasp of human creativity. Thus, designs obtained
using optimization algorithms are sometimes superior. Additionally, they are also
optimal for the conditions set in formulating the optimization problem unlike intuitive designs that could be further tweaked and optimized. We illustrate this using an
amplifying mechanism.
A lever, immortalized by Aristotle, comes to mind when we think of a mechanical
amplifier. When a pin joint (i.e., a revolute joint) is not practically viable (as is the
case with microfabrication), a simple lever is not a preferred choice. A flexure that
replaces a pin joint is also not a good choice because of high stress and limited
range of rotation. Furthermore, for large amplification ratio of output and input