This paper proposes a method of simultaneously calibrating magnetic localization and actuation systems for magnetically actuated robots. In this method, uncalibrated magnetic localization and actuation systems are calibrated simultaneously with minimal human intervention, which enables self-calibration, flexible reconfiguration, and long-term correctness of the system parameters. This method employs a bundle adjustment framework using a quadratic measurement model for sensors and the magnetic dipole model for actuators. The proposed method has been verified in comparison with finite element simulations and existing calibration methods for magnetic actuators and sensor arrays. In the experiments, the determinant of coefficient (R2value) was 99.84% for the sensor system and 99.45% for the actuator system after the calibration, comparable with individual state-of-art calibration methods of calibrating magnetic actuators and sensor arrays. This method has potential to improve the reconfigurability and long-term accuracy of magnetic robot localization and actuation systems, such as magnetically actuated capsule endoscopes.

This paper presents a magnetically actuated soft capsule endoscope for fine-needle aspiration biopsy (B-MASCE) in the upper gastrointestinal tract. A thin and hollow needle is attached to the capsule, which can penetrate deeply into tissues to obtain subsurface biopsy sample. The design utilizes a soft elastomer body as a compliant mechanism to guide the needle. An internal permanent magnet provides a means for both actuation and tracking. The capsule is designed to roll towards its target and then deploy the biopsy needle in a precise location selected as the target area. B-MASCE is controlled by multiple custom-designed electromagnets while its position and orientation are tracked by a magnetic sensor array. In in vitro trials, B-MASCE demonstrated rolling locomotion and biopsy of a swine tissue model positioned inside an anatomical human stomach model. It was confirmed after the experiment that a tissue sample was retained inside the needle.