Theoretical Investigation by Quantum Mechanics on the Tunnel Diode Effect of Electric Conductive Characteristics and Haptic Sensing in MCF Rubber

Abstract

By applying our developed intelligent fluid, magnetic compound fluid (MCF), to silicon oil rubber, we have made the MCF rubber highly sensitive to temperature and electric conduction. MCF is useful as the element material in haptic robot sensors and other related devices. In the present paper, we clarified the relationship between the electric current and the voltage under a tensile strain by utilizing the quantum mechanics theory on the multibarrier potential problem. The experimental results could be qualitatively explained by our proposed theory. The electrons can be moved between the solid materials by the tunnel effect. The relation between voltage and electric current is affected by the formation of the clusters, and it is changed by the application of heat. We also clarified experimentally the present MCF rubber useful in haptic sensors. Because the motions of humans and robots are different, the sensing of the rubber is different, depending on the placement. However, as for both motions of human and robot, there is no quantitative difference in the electric resistance among kinetic energy, momentum, and force. The sensing is also different based on the stiffness of the surface to which the sensor is adhered.

Quantum Mechanical Investigation of the Electric and Thermal Characteristics of Magnetic Compound Fluid as a Semiconductor on Metal Combined with Rubber

“…The change in the translated ratio of current T can be calculated by (C.7) in Appendix C, as shown in a previous report [33]. The obtained theoretical results are summarized as follows.…”

“…We used the same experimental apparatus as was used in a previous study [33], as shown in Figure 1. A load cell (LSM-50K-B, Minebea Co., Ltd., Japan) for measuring the compression force was enclosed by an inner metallic zipper sitting on the slider.…”

“…We used the same MCF rubber samples as were used in a previous study [33], which were hardened by being placed between nonmagnetic plates with a thickness of 1 mm and under the application of permanent neodymium magnets with a surface magnetic flux density of 0.56 T. The sample composites were Ni : Cu : MF (HS-50, kerosene base with 50 wt%, Taiho Industrial Co., Ltd., Japan): Dotite A : Dotite B : silicon oil rubber (SH9550, Toray-dow-corning Co., Ltd., Japan) = 1 g : 1 g : 1 g : 1 g : 1 g : 10 g to make improved MCF rubber samples, 11.5 mm × 16.2 mm × 0.855 mm, and HQ (carbonyl Fe particles, BASF Co., Ltd., Germany) : MF : SH9550 = 6 g : 4 g : 10 g samples, 13.1 mm × 18.4 mm × 0.5 mm. The dotites A and B are electric conductive glues with carbon powder.…”

“…A model has been proposed to explain the electric characteristics of ordinary electric conductive rubber, but the theoretical explanation with calculation using quantum theory has not yet been constructed, as discussed by Sherman et al [30] and by Sheng [31], although the tunnel effect due to the electric conductivity was identified, as well as the potential for the use of this rubber as semiconductor, as discussed by Meijer and Roggen [32]. Shimada [33] clarified theoretically the mechanism of electric conductivity in the rubber with metal particles by using quantum theory, as shown in Appendix C. Conductivity is possible because the electric current flows between the metal particles through the nonmagnetic rubber by the application of voltage because of the tunnel effect.…”

“…However, the role of MCF rubber as a semiconductor has not yet been shown. The previous report by Shimada [33] details about the thermal effect on the electric characteristics of MCF rubber and about the investigation of that effect using quantum theory. Therefore, in the present paper, we demonstrate and discuss the use of MCF rubber as a semiconductor.…”