Flexible Actuators for Small, Mobile, Special-Purpose Robots

A report discusses flexible microactuators for a proposed generation of small, mobile, special-purpose robots. Aspects of this topic were discussed in two previous articles in NASA Tech Briefs: "Thin-Film, Light-Energized Bimorph Micromechanical Actuators" (NPO-19607), Vol. 20, No. 8 (August 1996), page 11a and "Tetherless, Optically Controlled Nanorovers" (NPO-19606), Vol. 21, No. 3 (March 1997), page 92. To recapitulate: insectlike robots equipped with microsensors and/or micromanipulators are proposed for use in applications as diverse as remote exploration, surgery, and surveillance. These robots would move by the electronically and/or photonically controlled bending of flexible cantilever-beam bimorph microactuators (composites of thin piezoceramic films on strong polymeric substrates) that would be analogous to animal limbs except that they would not be jointed. The report emphasizes that in comparison with other actuators with equal areas, the proposed microactuators would offer high ratios of generated force to input power, and that unlike actuators micromachined from silicon, the proposed microactuators would not be restricted by the clamping effects of substrates. The report reviews the state of the art, discusses the principles of operation and the rationale for using the microactuators, describes potential applications, and proposes research to develop advanced piezoceramic materials for microactuation.