This paper presents a novel swimming method mediated by traveling waves in elastic tails. The propulsion method is potentially appropriate for maneuvering microrobots inside the human body. The swimming action relies on the creation of a traveling wave along a piezoelectric layered beam divided into several segments. This requires that a voltage with the same frequency, but different phases and amplitudes, be applied to each segment. The swimming pattern was analyzed theoretically by solving the coupled electric-elastic-fluidic problem, and was optimized to attain reasonable thrust. It was found that despite extreme size limitations, a tail manufactured by current microelectromechanical-devices technology, using piezoelectric material, is able to swim in water at a speed of several centimeters per second. The swimming theory was verified experimentally using an upscaled model that produced propulsion of 0.04 mN, which matches closely the theoretically predicted propulsion.

Medical doctors use radiology, endoscopy and smart pills to inspect the human body's inner content. Nowadays, self-propelled micro robots are developed to fulfill these tasks which use types of crawling techniques to advance. This paper suggests a novel swimming method, which creates a traveling wave in an elastic tail made of piezo-electric actuators, for propulsion of a micro-robot in the body. The novel swimming method was analyzed and optimized analytically by solving the coupled elastic/fluidic problem. It was found that under the extreme size limitations a tail manufactured by current MEMS technology is able to swim at the order of several mm/sec in water.