flexure stage

FLEXURE-BASED complaint mechanism is a kind of mechanism that works by its elastic deformation. As compared with conventional rigidbody mechanisms, it offers the advantages of fast response, no backlash, and no friction. Hence, it has been widely used in the field of micro/nanopositioning, micro/nanomanipulation, and atomic force microscopy (AFM). From the perspective of function, the complaint mechanisms are mostly used for guiding, decoupling, and amplifying purposes. To match the feature of complaint mechanisms, a piezoelectric actuator (PEA), which operates based on the inverse piezoelectric effect of piezoelectric ceramics, has been employed extensively. PEA offers some similar advantages as the complaint mechanisms, e.g., fast response and unlimited resolution.

MSc student Zeyi Wu and Prof. Qingsong Xu designed, modeled, optimized, fabricated, and tested a compact 1-DOF vertical micro/nanopositioning stage for the above purpose. The optimized
design variables result in a stage size of 58
× 20 × 15.5 mm3 (length × width × height), which is more compact than the existing flexure-based vertical positioning stage. Finite-element analysis (FEA) simulation results reveal that the stage exhibits the resonant frequency of 372.77 Hz, maximum free output displacement of 181.18 μm, and maximum output displacement of 117.55 μm along with a maximum bearable loading over 8 kg. Experimental results demonstrate that the stage owns the resonant frequency of 199.22 Hz and maximum output displacement of 97.32 μm. The discrepancies between the experimental and simulation results are mainly attributed to the fabrication error, assembly error, and simulation error. Closed-loop tests with PID feedback control show that the stage provides a positioning resolution better than 10 nm along with satisfactory response speed and accuracy for motion tracking tasks. In the future work, the vertical stage will be mounted onto an XY stage to perform micro/nanopositioning applications in 3-D space.

The research is published in IEEE Transactions on Automation Science and Engineering. Full paper can be obtain from here.