Nonlinear swimming magnetically driven microrobot influenced by a pulsatile blood flow through adaptive backstepping control having weight estimation

In order to improve the microrobot dynamics and control, characterizing the underlying factors contributes to a better understanding of this procedure for practical applications such as drug delivery and surgery. Therefore, MEMS technology is considered. Aggregating of the ferromagnetic particles having the polymer bonded can be considered as a swimming microrobot. It can be observed by magnetic resonance imaging (MRI) to achieve therapeutic purposes. This study aimed to represent a control system navigating the magnetic microrobot in a cylindrical blood vessel along a reference trajectory. Firstly, a backstepping controller is implemented to control the nonlinear model. The microrobot in the blood vessel encounters pulsatile blood flow that causes a nonlinear drag force on the microrobot. Moreover, considering the variability and uncertainty in the weight of the microrobot to achieve the control objective, an adaptive backstepping control approach is proposed to estimate the microrobot's weight. As a result, the proposed control system’s satisfactory performance and the microrobot weight estimation during the reference trajectory are illustrated through the MATLAB simulation.