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Development of Control Circuit for Inductive Levitation Micro-Actuators
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1  Karlsruhe Institute of Technology - Institute of Microstructure Technology
2  Innopolis University - Institute of Robotics and Computer Vision (registering DOI)

The control circuit for inductive levitation micro-actuators is developed in this research. The circuit performance and its electrical parameters are discussed. The developed control circuit was fabricated on a 4-layer PCB board having a size of 60 mm by 60 mm. It consists of a generator based on high-speed Flip-Flop components and a current amplifier build on a bridge configuration. The circuit is able to generate ac current with squared shape in a range of frequency from 8 to 43 MHz and with peak-to-peak amplitude up to 420 mA. To demonstrate the efficiency of the developed circuit and its compatibility with the micro-actuation system, an inductive levitation micro-actuator was fabricated by using 3D micro-coil technology. The device was composed of two solenoidal coil design, which consists of levitation and stabilization coil, having 2 mm and 3.8 mm in diameters, respectively. The levitation coil has 20 turns of a gold wire of a 25 µm diameter, while the stabilization one has 12 turns similar to the micro-structure presented previously by our group. Using the developed control circuit, the micro-actuator was successfully excited and it demonstrated the actuation of aluminum disc-shaped micro-objects having a diameter of 2.7 and 3.2 mm and, for the first time, an aluminum square shaped micro-object having a side-length of 3.4 mm at a frequency of 10 MHz. To characterize the actuation, the levitation height and the rms amplitude of current were measured. In particular, we showed that the square shaped micro-object can lift up on a height of 100 µm with rms current of 160 mA. The characterization is supported by the simulation using a 3D model based on the quasi-FEM approach.

Keywords: micro-actuators; micro-systems; levitation;