Preliminary design of a model-based position controller for magnetic microfibers

Polymer fibers embedded with paramagnetic particles bend when placed in a magnetic field. The fiber can be manipulated by varying the coil current in an electromagnet. The operating range of the fiber is divided into one region with stable equilibria and one region with unstable equilibria. In this paper, fiber dynamics are modeled as a rigid bar. This model is used to develop a nonlinear controller for the position of the fiber over the whole operating range. An experimental platform for sensing and controlling fiber position was developed. The controller is tested experimentally and results are presented. The results show that the controller can control the position of the fiber in the unstable region despite model uncertainty.