High Gain Observer for backstepping control of a MRI-guided therapeutic microrobot in blood vessels

This paper reports precise modeling and controller/ observer design for a microsized polymer aggregate of magnetic particles inside an artery, using a Magnetic Resonance Imaging (MRI) device for supplying propulsion in order to achieve targeted chemotherapy. Non-Newtonian behaviour of blood is taken into account, as well as wall effects and interactions, resulting in a highly nonlinear model. A High Gain Observer is designed to reconstruct the unmeasured state, so that a backstepping controller can be synthesized. Efficiency and robustness to noise of this controller/observer pair is then illustrated through simulations results.