Dexterous nanomanipulation of 2D hydrogel microstructure for 3D assembly by multi-robot cooperation

Robotic nanomanipulation has achieved a wide range of applications on biomedicine and facilitated a revolutionary breakthrough for it. This paper presents a dexterous nanomanipulation system with three robots coordination for the reconstruction of three-dimensional (3D) artificial microstructure. It is set up with two main components. One is the nanomanipulator with 4 degrees of freedom (DOFs) and 30nm operation precision. The other is a vision sub-system developed to provide feedback for coordination control among the three robots. Based on the cooperation, we propose a pick-up method of 2D hydrogel microunits and integrate an assembly strategy to fabricate a 3D substitute for tissue engineering. Pickup of 2D microstructures largely determines the success of 3D assembly. Therefore, effectiveness of pick-up is investigated by kinetic analysis, Matlab simulation and pick-up experiments. These results demonstrate that the proposed method is feasible for circular 2D structure assembly. However, it is not universal for any shapes of 2D units. Thus, three new pick-up methods are discussed to seek for higher flexibility of our system.