Compact Digital Microrobot Based on Multistable Modules

Current digital microrobots are mainly composed of bistable modules and flexible structures. Unlike conventional microrobots, they are based on mechanical stability instead of complex control strategies in order to reach precise and repeatable discrete positioning. By design, their number of stable positions depends on the number of bistable modules. As a consequence, increasing the robot workspace requires using several modules. In this case, the robot size increases and its miniaturization becomes complex and non-intuitive. To address this issue, a multistable module has been developed to reach several stable positions. In this letter, a new generation of digital microrobots is proposed. Based on two multistable modules and flexible structures, the new microrobot can reach a large workspace while having a small footprint. Concretely, the robot size decreases by 26% while the number of stable positions increases by 950% in comparison with the first generation of the digital microrobot. A prototype is designed, fabricated and characterized experimentally. Preliminary results show a good agreement between the expected and the achieved workspace. The robot achieves 169 stable positions with a discrete step of 4.125 \mum and a resolution of 150 nm. With these capabilities, the robot paves the way for promising perspectives and applications, in particular precise micro-manipulation in confined environment such as a Scanning Electron Microscope.