Dynamic Modeling of Electromagnetic Control System for Robust Controller Design

In this work, the problem of controlling a fully untethered microrobot both in position and orientation in five degrees-of-freedom using electromagnetic control systems is considered. We focus on the OctoMag and MiniMag systems that were developed at the Institute of Robotics and Intelligent Systems of the ETH Zurich. Starting from magnetic formulas for these systems, a new dynamical model was developed that includes the dynamics of the agent to be controlled, as well as the dynamics of the electromagnetic control system. A linear uncertain version of this model was used in controller synthesis, while the amount of acceptable uncertainty was investigated by studying the singular values of a characteristic system matrix, the Force-Actuation Matrix. A simple PID and a robust H∞ controller using DK-iteration method were synthesized for a particular configuration of the system. Simulations and exper- imental results show the effectiveness of the used approach