Toward Electrostatic Levitation of Macroscale Machines

Contact-less suspension of macroscale objects has traditionally been reserved almost exclusively for magnetic systems containing copper, steel laminations, and permanent magnets. Electrostatic systems, on the other hand, have been left out primarily due to their much lower force density in atmosphere. However, the ability to levitate nonferromagnetic materials, and recent developments in high-torque density electrostatic motors may allow for practical electrostatic suspensions at meaningful scales. To transport electrostatic forces out of the micro-electro-mechanical systems scale and potentially into the power domain, this article proposes a unique electrostatic bearing for vacuum condition. Basic operating principles, force analysis, linear system model, and control strategy are presented, then experimentally validated using a prototype bearing. Stable levitation of a 62 g, 130 mm diameter aluminum disk is achieved at an air-gap length of 0.5 mm, requiring approximately 27.6\,\mathit{\mathrm{\mu }}\mathrm{W} for suspension.