Design, manufacture, and two-step calibration of a piezoelectric parallel microrobot at the millimeter scale for micromanipulation

The design, manufacture, and calibration of a miniaturized piezoelectric parallel microrobot at the millimeter scale are performed. A composite origami manufacturing process is developed to realize a complex three-dimensional structure from multilayer composite materials through laser cutting, lamination, release, folding, curing, and assembly. The size of the microrobot is 28 × 29 × 29 mm, with a weight of 2.94 g. A two-step calibration strategy is proposed to eliminate the error identification failure caused by the discontinuity of error transmission and coupling errors. The coupling errors of the amplification mechanism are identified using particle swarm optimization, and the errors of the parallel mechanism are identified by the least squares method. Calibration experiments of six trajectories show maximum and RMS positioning error drops of 15.1 and 6.9 µm, from 48.9 to 23.3 µm, respectively. Additionally, a potential application experiment is conducted. The microrobot scans a 4 × 4 microwell array in 2.4 s with a positioning velocity and average error of 125 ms/well and 8 µm, respectively. The potential of the microrobot for rapid positioning and high-throughput screening is demonstrated.