Velocity Control with Gravity Compensation for Magnetic Helical Microswimmers

Magnetic helical microswimmers, which swim using a method inspired by the propulsion of bacterial flagella, are promising for use as untethered micromanipulators and as medical microrobots. Man-made devices are typically heavier than their fluid environment and consequently sink due to their own weight. To date, methods to compensate for gravitational effects have been ad hoc. In this paper, we present an open-loop algorithm for velocity control with gravity compensation for magnetic helical microswimmers that enables a human operator or automated controller to command desired velocity intuitively, rather than directly controlling the microswimmer's orientation and rotation speed. We provide experimental verification of the method. (C) Koninklijke Brill NV, Leiden and The Robotics Society of Japan, 2011