Magnetic-based minimum input motion control of paramagnetic microparticles in three-dimensional space

Magnetic drug carriers such as microrobots and paramagnetic microparticles have the potential to increase the therapeutic indices by selectively targeting the diseased tissue. These magnetic microobjects can be controlled using magnetic-based manipulation systems. In this study, we analyze a minimum input motion control to minimize the currents at each of the electromagnets of a magnetic system. This minimum input control allows us to achieve point-to-point closed-loop motion control of microparticles in the three-dimensional space, at an average speed of 198 μm/s, and maximum root mean square position tracking error of 104 μm. The minimum input control system is further evaluated by comparing norm-2 of its resulting current vector to the current vector of a proportional-integral (PI) control system. This comparison shows that the minimum input control achieves 11% decrease in the current input, as opposed to the PI control system. However, the PI control system achieves 43% and 285% higher average speed and positioning accuracy, respectively, as opposed to the minimum input controller. The magnetic-based minimum input control can be used to perform closed-loop control of magnetic microrobots while decreasing the current input.