Model-based real-time control of a magnetic manipulator system

Precise magnetic manipulation has numerous applications, ranging from manufacturing to the medical field. Owing to the nonlinear nature of the electromagnetic force, magnetic manipulation requires advanced nonlinear control. In this paper, we design and experimentally evaluate two nonlinear controllers for a magnetic manipulation (Magman) system, which consists of four electromagnetic coils arranged linearly. The current through the coils is controlled in order to accurately position a steel ball, rolling freely in a track above the coils. We benchmark two nonlinear control methods, namely feedback linearization and a constrained state-dependent Riccati equation (SDRE) control. These methods are chosen due to their widespread use in academia as well as industrial applications. On the actual setup, constrained SDRE has performed considerably better in terms of the settling time, overshoot, and the amount of control effort when compared to feedback linearization.