“…For magnetic capsule robots or magnet-tipped tethered devices for medical applications, whose size can range from a few millimeters to centimeters in terms of the device diameter, localization and tracking of the device have been obtained from internal or external sensing (e.g., embedded Hall-effect sensors and inertial measurement units ,, or externally arranged Hall-effect sensor arrays ,,− ) or real-time imaging (e.g., internal imaging using endoscopy cameras, , external imaging through optical or stereocameras, ,,, X-ray fluoroscopy, , magnetic resonance imaging, or ultrasound). The state observation from device tracking and localization through real-time sensing or visual feedback through imaging allows for the implementation of closed-loop feedback control or learning-based, data-driven control for intelligent magnetic manipulation. For small-scale magnetic soft robots, however, device tracking and localization for closed-loop control and advanced manipulation through internal or external sensing can be challenging due to their constrained size, and the state observation would rely mostly on the visual feedback from real-time external imaging.…”