Closed Loop Control of a Tethered Magnetic Capsule Endoscope

Area of Science:

• Robotics
• Biomedical Engineering
• Magnetic Actuation

Background:

• Magnetic field gradients are the most feasible mechanism for gastrointestinal capsule endoscope actuation.
• The inverse quartic magnetic force variation necessitates precise robotic control of driving magnets.
• Typical systems use serial robots to actuate capsules with embedded magnets.

Purpose of the Study:

• To present a tethered capsule endoscope system with closed-loop control.
• To achieve 2-DOF position and 2-DOF orientation control for the capsule.
• To enable 6-DOF capsule localization using external magnetic fields for feedback control.

Main Methods:

• Developed a closed-loop control scheme for capsule position and orientation.
• Established a relationship between serial robot joint parameters and magnetic force/torque.
• Validated the methodology through dynamic simulation and an experimental platform.

Main Results:

• The tethered capsule system demonstrated accurate trajectory following in both position and orientation.
• 6-DOF localization of the capsule was achieved using the external magnetic field.
• Control accuracy was found to be acceptable for colonoscopy procedures.

Conclusions:

• The presented tethered capsule system offers a viable solution for controlled gastrointestinal endoscopy.
• Precise magnetic actuation and feedback control are key to achieving diagnostic accuracy.
• This technology has the potential to improve colonoscopy procedures.