**4. Conclusions**

18 Will-be-set-by-IN-TECH

**Figure 24.** Movement of the model filmed by a high-speed camera, and the image was captured at

intervals of 50 ms. The total moving distance was 6.2 cm.

This chapter presents a new type of magnetic fluid, a rotational drive and an advanced locomotion method with simple magnetic field.

First, a new type of magnetic fluid and a rotational drive using a simple magnetic field by use of magnetic fluid were presented. It is clear that our proposed driving motions are created by collision of the magnetic particles with the outer cover and the flow resistance between the particles and the cover. The drive for the rolling model was achieved from a small-scale external magnetic field generator and a simple magnetic field control. The device in this study could be applied to new mechanical elements and micro internal rolling objects as a useful medical tool.

Second, an advanced locomotion method that produced non-slipping motion in soft and closed environment by use of magnetic fluid were presented. New movement principle of the robot, which had a soft and deformable body that could move through a confined space was proposed. The mechanism of a toy water snake was applied to this principle. Magnetic particles inside the water balloon were affected by the external magnetic field and push the inner side of a balloon to the direction of a magnetic field. Experimental prototype to verify the proposed principle were conducted, the sliding movement was measured using the model. Confirmatory experiments of movement were conducted in the two sheets that imitated internal organs, the total moving distance was 6.2 cm. Drive a rolling model by simple magnetic field control were succeeded.
