On-line sensing and display in Atomic Force Microscope based nanorobotic manipulation

Atomic Force Microscope (AFM) has been used to manipulate nano-objects and modify sample surface in nano-scale for many years. But positioning error and losing objects in the manipulation are still hindering the efficiency of AFM based nanomanipulation. Positioning error, which is caused by random drift such as thermal drift and nonlinearity of piezo-actuator, leads AFM tip to a wrong position and missing the object during manipulation. Losing objects, which is due to the small touching area between AFM tip and the object, means that the AFM tip slips over or slips aside the nano-object during manipulation. There is no existing method available to solve these two problems simultaneously, which results in a low efficiency of nanomanipulation. In this paper, an On-line Sensing and Display (OSD) method is proposed to eliminate the positioning error caused by random drift and find the actual position of object. Since the process of OSD can be finished in a very short time, it is almost transparent to the operator. Experiments of manipulating some nanomaterials such as nano-particles and nano-rods shows that not only can random drift be effectively detected and compensated, but also the actual position of losing object can be found and updated to the visual feedback display. The paper presents the theoretical development as well as implementation study for the OSD method. The experimental results presented in the paper have shown that the OSD method has significantly improved the efficiency of the nanomanipulation.