**3. Deformable robot actuation by magnetic particle**

The endoscope, which is a flexible tube, is used to examine the interior of the human gastrointestinal tract. The standard endoscope is inserted via the mouth or the anus and manually pushed and pulled into the organ to be examined. In contrast, a capsule endoscope is swallowed by a patient and naturally exits the body within eight hours. [10] Another capsule endoscope mounts a permanent magnet inside the body, rotates and moves actively by applying a rotational magnetic field. [11][12] M. Shikanai et al. developed a robotic endoscope that consists of front and rear bodies with bidirectional rotational helical fins. [13] The front and rear bodies are connected by a DC motor. The robot advances through the

#### 12 Will-be-set-by-IN-TECH 436 Smart Actuation and Sensing Systems – Recent Advances and Future Challenges

intestines by clockwise rotation of the front body and anticlockwise rotation of the rear body. These capsule-type robots require power supply wires and a permanent magnet. A potential problem with this design is that the rotational drive could cause engulfment. P. Glass et al. developed new controllable capsule endoscopes, the prototypes have used shape memory alloy or micro motors to press elastomer micropillar legs into the gastrointestinal lining to anchor the capsule in place.[14][15] Bio-inspired adhesives by the elastomer micropillar legs to stick the capsule to the intestinal lining allow the clinician to control the progress of the capsule along the patient's gastrointestinal tract. Another type of capsule robot mounts a ferromagnetic material inside the body and is moved by applying a gradient magnetic field. [16] The limitation of this design is that slipping locomotion is affected by the surface friction of organs. A magnetic particle has been reportedly developed that is lighter than liquid, and on mixing with liquid creates a new impetus. [17]

This section presents an advanced locomotion method that produces non-slipping motion in digestive organs and the abdominal cavity by developing an endoscopic robot. The developed endoscopic robot is soft, deformable, and can move through a confined environment of internal organs.
