Model-free and Uncalibrated Visual-feedback Control of Magnetically-Actuated Flexible Endoscopes

Magnetically-actuated flexible endoscopes (MAFE) have been well used in minimally-invasive surgery because they can be steered by a magnetic field thus more flexible than traditional endoscopes. Model-free and uncalibrated visual-feedback control makes it possible to manipulate MAFE with a magnetic field without external tracking systems. Because no extra sensor is required to obtain position and posture information, the size of MAFE can be made smaller. However, the traditional control method focuses on 2DoF control, which lacks control over the posture of the end of MAFE. This may result in unnecessary contact between MAFE and tissue and cause injury during the advancement of the endoscope. In this letter, we propose algorithms to enhance the pose control of MAFE to 4DoF and 5DoF based on model-free and uncalibrated visual-feedback control. Experiments in structured environments verify that the control algorithms are able to realize 4DoF manual navigation and 5DoF automatic navigation.