**3.4. Results and discussions**

16 Will-be-set-by-IN-TECH

**Figure 22.** Measuring setup of movement condition. The model is pulled with a wire, and it passed between two sheets that simulated internal organs. The gap between the two sheets is gradually

> interval[mm] friction(a+b)[N] deformation(c)[N] 2.31 0.378 2.15 0.346 1.99 0.328 1.81 0.304 1.73 0.284 1.69 0.263

Fig.23 shows a graph of the measured magnetic force exerted by magnetic particles inside the water ballon. The magnetic force of 0 - 1.5 N can be applied to the model by the magnetic field

Eq.(3) shows theoretical formulas of the magnetic force *F*, measured values are consistent with

*dH*

*dx* (3)

*m* = *χeff HV* (4)

*F* = *m*

increased.

generator.

theoretical ones.

**Table 1.** Measured value of movement condition

The movement of the model is shown in Fig.24. The movement was filmed by a high-speed camera, and the image was captured at intervals of 50 ms. The value written on each figure is the movement distance. The head point on which the triangle is marked moved, while the position of the black band did not move between the two sheets, confirming movement without slippage. The seam part of the cylindrical balloon skin stopped moving, and the total moving distance was 6.2 cm. The moving distance increases by reducing the width of the seam; the method of manufacturing the cylindrical balloon will be improved in the future. Periodic expansion and contraction were observed in the entire film. To improve the efficiency of movement, appropriate material of the cylindrical balloon and sufficient amount of water inside the balloon should be used.

The method of applying the magnetic field to the tube and the patient's body is described. A method using a midair solenoid, as shown in Fig.25, is examined here. The tube or the specimen material is placed in the solenoid, and the part to which the magnetic field is applied is set on the edge of the coil. The magnetic gradient on the edge of the coil generates the magnetic field necessary for movement.

**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.

**Figure 25.** Method of applying the magnetic field to the tube and the patient's body using a midair solenoid.
