Analysis and Motion Control of a Centrifugal-Force Microrobotic Platform

This paper presents the analysis, design, and closed-loop motion control of a mobile microrobotic platform capable of micrometer positioning on a plane. The mobile microrobot, including chassis, actuators, drives, microprocessor, and electronics, is of low cost (less than $20), can be fabricated rapidly and is made of commercially available components. Its motion is induced by centrifugal forces generated by two vibration motors installed inside the platform body. The asynchronous operation of the vibration motors is shown by simulation to result in planar motions of two degrees-of-freedom locally, with micrometer resolution. A motion controller has been designed to generate controlled motions using sets of motor angular velocities. A prototype has been developed and used to validate the motion principle and the controller efficacy. Open loop experiments show that the platform motion resolution is approximately 20 μm, while its speed is greater than 2 mm/s. Closed-loop experiments demonstrate a 5 μm resolution, i.e., a fourfold improvement compared to the open loop experiments. The low cost, the rapid fabrication, and the micrometer motion resolution suggest that this microrobotic platform is a promising solution for low-cost microfactories, where a group of such robots performs high throughput, advanced microassembly of microsystems.