Operating in the microworld and nanoworld
Precise manipulation primarily calls for a clear understanding of the physical specificities of submillimetre-sized objects, on the knowledge of which adapted manipulation tools and grippers can be designed. For this purpose, a dedicated model for adhesion forces between gripper and object was devised within the MICRON project, taking into account realistic working set-ups in terms of geometry, contact area and environmental conditions. In order to extract guidelines for the design of micro-manipulation end-effectors, extensive experiments with different gripping tools were performed at the Scuola Superiore Sant'Anna in Italy. The results were compared with the theoretical analysis. The gripping functionality of the micro-gripper was ensured with the integration of voltage-driven piezo-electric actuators. For manufacturing three-dimensional (3D) shaped grippers arms of stainless steel, wire electrical discharge machining (EDM) processing was utilised. The total gripper length is approximately 12 mm and the minimum tip thickness approximately 70 μm, essential for the assembly of meso-scale components, both rigid and flexible. For the micromanipulation of living cells, such as injection of synthetic molecules, peptides and proteins, a new process for the micro-fabrication of a needle-like structure was developed. The realised micro-needle has an outer tip of 2 μm, thin enough not to damage the cell. The next step was to establish manipulation strategies and corresponding control schemes of the micro-robots rotational actuator, on which the grippers and supporting needle were fixed. Microsystems will have an increasingly important role to play in minimally invasive medical procedures, both diagnostic and therapeutic. The work carried out by the project partners made the automated manipulation of micrometer-scaled objects possible, with nanometre precision.
