Steering a ferromagnetic particle by magnetic feedback control: Algorithm design and validation

We present results for planar manipulation of a single drop of magnetic nano-particles (a ferrofluid) in a liquid by feedback control of an array of electromagnets. Control design is based on a first-principles physical model of the magnetic fields, the resulting magnetic forces, and opposing viscous drag on the ferrofluidic drop, and it exploits the nonlinear (quadratic) nature of the dependence of the magnetic force on the electromagnet actuations. An ability to control the droplet along arbitrary trajectories is verified both in simulations and in an experiment.