Achieving three-dimensional automated micromanipulation at the scale of several micrometers with a nanotip gripper

Three-dimensional (3-D) automated micromanipulation at scale of several micrometers using a nanotip gripper is presented. The gripper is constructed from protrudent tips of two independently actuated atomic force microscope (AFM) cantilevers and each cantilever. A protocol allows these two cantilevers to form a gripper for grasping and releasing the microspheres to target positions without obstacle of adhesive forces in air. For grasping, amplitude feedback from the dithering cantilevers is employed to locate the grasping points by laterally scanning the side of the microspheres. Real time force sensing is used to monitor the whole process of the pick-and-place with steps of pickup, transport and release. For trajectory planning, an algorithm based on the shortest path solution is used to obtained 3-D micropatterns with high efficiencies. In experiments, microspheres with diameters from 3 ¿m to 4 ¿m were manipulated and 3-D micropyramids with two layers were achieved. 3-D micromanipulation and 3-D microassembly at the scale of several microns to submicron could become feasible through the newly developed nanotip gripper.