Automated microassembly using precision based hybrid control

Microassembly is an enabling technology for micro manufacturing that offers well-known pathways to building heterogeneous microsystems with a higher degree of robustness and more complex designs than monolithic fabrication. The success of assembly in micro domain, however, is directly related to the level of precision automation employed. Control and planning are two defining factors for the microassembly yield and its cycle time. Assembly at the microscale harbors many difficult challenges due to scaling of physics, stringent tolerance budget, high precision requirements, limited work volumes, and so on. These difficulties warrant new control and planning algorithms, different than their macro-scale counterparts. In this paper, we use precision metrics to formalize a hybrid controller for automated MEMS assembly. In the past, we formulated the “high yield assembly condition (HYAC)”, which gives a quantitative condition for the success and failure of compliant microassembly. Using this quatitative tool, we formalize a precision-adjusted hybrid controller switching between open, closed, and calibrated operation in the microassembly cell. Simulation and experimental results for the assembly of a microspectrometer are presented to indicate that the proposed hybrid controller lead to high yields at faster cycle times than traditional precision control methods.