Impedance Regulation-Based 3-D Selective Manipulation of Collective Microrobots

Magnetic actuation is a promising approach in the robotic manipulation field, enabling wireless manipulation for small-scale operations. However, selective three-dimensional (3D) manipulation of multiple magnetic microrobots under global magnetic fields remains a challenge. This paper presents a dynamic magnetic modeling and vision-guided control strategy to realize 3D manipulation of magnetic microrobots, including patch-robot-assisted collective delivery and microrobot screening. An impedance regulation-based position control method is proposed, leveraging theoretical analysis of electromagnetic forces and fluid drag to accommodate microrobots with diverse morphologies. Through trajectory motion experiments, our control strategy ensures that the mean absolute errors (MAE) of the microrobots are consistently below 200 μm. By utilizing patch robot adhesion and differential magnetic responses among the microrobots, this strategy enables selective manipulation and collective sorting in a 3D space. Applications in patch-robot-assisted delivery, collective sorting and screening are validated. The proposed approach advances magnetic microrobot control by enabling spatially selective operations critical for biomedical tasks.