Image-Based Visual Servoing of Helical Microswimmers for Planar Path Following

Magnetically actuated microswimmers have attracted researchers to investigate their swimming characteristics and controlled actuation. Although plenty of studies on actuating helical microswimmers have been carried out, robust closed-loop controls should be still explored for practical applications. In this paper, we proposed a data-driven model-free method using Image-Based Visual Servoing (IBVS), which uses features directly extracted in the image space as feedbacks. The IBVS method can eliminate camera calibration errors. We have demonstrated with experiments that the proposed IBVS method can enable velocity-independent path following of an arbitrarily given path on the plane, which permits a better experience of user interaction. The proposed control method is successfully applied to obstacle avoidance tasks and has the potential for the application in complex circumstances. This approach is promising for biomedical applications. Note to Practitioners-This paper is motivated by the problem of driving a small-scale swimming robot with a helical body by magnetic fields along a predefined path. The proposed new closed-loop control uses features directly extracted in the image space as feedbacks. We demonstrated with experiments that the helical swimming robot can follow an arbitrarily given path on the plane using the proposed control method. The proposed control method is also successfully applied to obstacle avoidance tasks.