Summary: Shorya Awtar MIT Confidential 1
Title: Planer flexure mechanisms with two, three or five degrees of freedom
Inventors: Shorya Awtar and Alexander H. Slocum
Introduction and Background
There exist many two-axes planer flexural mechanisms that allow for small translations
within the plane of the flexure. Most of these designs incorporate a stacked assembly
where one linear stage in mounted perpendicular on a second linear stage resulting in a
relatively bulky design. Nevertheless, in this arrangement the two axes are entirely
decoupled and the actuation of one axis has no effect on the other. Such an assembly is
commonly referred to as a `serial design' in robotics terminology. In some clever serial
designs, the above-mentioned stacking is achieved within a plane.
The disadvantage of serial designs is that the actuator for the second stage has to be
mounted on the moving member of the first stage. This not only makes the design
unnecessarily complex but also limits the system dynamic performance, for example,
speed of response. Ideally, it is desirable to mount the actuators for both the axes on
ground, i.e., the fixed base.
Furthermore, if one tries to increase the degrees of freedom of a flexural mechanism
using the serial approach, the design becomes increasingly cumbersome and bulky.
Therefore, instead of taking this path designers usually develop assemblies that are based
on closed-chain parallel designs (as opposed to serial designs). In this kind of designs