Precise control of magnetic soft microrobot in flowing environment

Abstract

Microrobots have demonstrated attractive advantages for biomedical use, ranging from cargo delivery to invasive therapies. However, it remains a challenge to develop a universal control method for various microrobots to guarantee the precision of microrobot-based executions and further spread their applications. Herein, we propose an iterative learning control (ILC) method that can achieve precise position control for microrobots in a bionic flowing environment. Although the kinematics system of the microrobots and flowing environment has severe nonlinearities and uncertainties, the model- free control method, ILC, can optimize the input gradually to accurately accomplish microrobots’ arrangements, including position control and drug release. Oil-droplet-based magnetic soft microrobots are utilized as control objects to prove the advantages of the proposed control method. Two electro- magnets are set up as actuation devices, and a microchannel with a flowing medium mimics the vessel environment. By rigorous mathematical analysis and numerous experiments, the proposed method is verified to be effective, and the results show that the microrobots can be precisely controlled to the desired position in the flowing environment. These results pave a novel and accessible path to achieve precise position control for various microrobots.