Compliant Microgripper with Parallel Straight-line Jaw Trajectory for Nanostructure Manipulation

INTRODUCTION Compliant gripping mechanisms are particularly suited for precision manipulation of microand nanoscale objects by virtue of having zero backlash, no parasitic columbic friction effects, and often only requiring one actuator to close two gripping faces symmetrically about a centerline of action. Many previous compliant gripping mechanisms use a parallelogram structure (Fig. 1a) to close parallel jaws [1,2,3]. These designs are effective in gripping micronsized objects, but the gripping faces inherently move along an arc-shaped trajectory (Fig.1b). Straight-line jaw motion may be desired for micromechanical tension/compression tests, and for gripping soft objects such as cells, gels, and assemblies of nanostructures such as carbon nanotubes. These and other applications are sensitive to normal and shear loading. In general, the transverse component of the jaw motion constitutes a coupling of two sources of transverse error (δ) in the mechanism: kinematic error, defined as the motion path of an equivalent rigid link model, and elastic error stemming from finite material elasticity.