Positioning of microrobot in a pulsating flow using EMA system

Abstract

The purpose of this paper is the positioning control of the microrobot in a pulsating flow using electromagnetic actuation (EMA) System. Several types of EMA systems which are 2-dimensional and 3-dimensional locomotion control of microrobot were proposed and studied. Generally, these conventional researches of EMA systems showed the results of locomotion of microrobot in a fluid without flow. However, in the case of test of microrobot in a blood vessel, it is required that the experiments of locomotion should be performed in a pulsating flow like bloodstream. For that reason, we carried out basic locomotion research of the microrobot in the pulsating flow. For this experiment, we used simple 1-dimensional EMA system which consists of a pair of Helmholtz and Maxwell coils, and we set up a vascular simulator which can generate pulsating flow in the vessel phantom. The magnetized microrobot was inserted in the vascular simulator. The electromagnetic force which affects the motion of the microrobot was controlled by regulating input current to EMA system. The input current regulation was performed by considering the magnitude of flow rate and drag force of fluid to the microrobot. To measure the pressure variance of a pulsating flow in the vascular phantom, the pressure transducer was placed in front of the region of interest (ROI) and the control input which compensates the drag force to microrobot was generated by using the transducer signal. In addition, the position of microrobot was acquired through the CMOS camera and the feedback control loop was also implemented for accurate positioning control. The performance of the positioning control was evaluated by in-vitro experiments using vascular simulator. In addition, the feasibility of the position control of the microrobot was also evaluated by in-vivo animal experiments.