A passive walker can walk down shallow slope with no energy source other than gravity. This motion is very attractive because its gait is really natural and ideal. Moreover, the walker can exhibit a stable limit cycle. Dynamics of passive walking is very interesting target and important for understanding human locomotion and developing the biped robots. In this paper, we introduce principles and applications of passive walking.

　Real haptics has been a unsolved problem since its starting in 1940's. After many R&Ds including the early works in US and other countries, the bilateral control designed in acceleration space solves this issue. The quality of the touching and tactile sensation is heavily depends on transperancy between master side and slave side. The robust motion control which is equal to the acceleration control gives high transperancy. The real haptics is now key concept in 21st century where QOL should be the basis of the society. The various examples are also shown.

　KEIROKAR assistive system is assistive technology which can reduce fatigue and load of human workers and also can keep their physical performance to perform their work. This tutorial paper describes the concept of KEIROKA assistive system and Smart Suit ® as a practical example of KEIROKA system. The application of information and robot technology to control and design Smart Suit and its future prospects will be remarked.

　In this article, the author introduces two aquatic robots being developed in the author's laboratory: a miniature aquatic robot propelled by resonance of elastic plate and MINAMO (Multidirectional INtuitive Aquatic MObility). The former is a robot including a vibrating motor in the body shell and having an elastic plate fixed on the outer as a fin. The latter is a personal vehicle on water that realizes the straight and whirl movement by the control of the rider weight shifting.

　Ordinary electrolytic polymerization has involved plastic-type polymer solutions. Rubber, especially natural rubber, has not been focused on until recently owing to the fact that electrolytic polymerization has only a very small effect on rubber. However, when the C=C bonds of natural rubber is focused on, the same electrolytic polymerization is applicable to be enlarged on the natural rubber if a magnetic field and a filler are aided. With the application of a magnetic field and a magnetic responsive fluid such as magnetic compound fluid (MCF) as a filler, the effect of electrolytic polymerization on NR-latex such as plastic-type polymer solutions is enhanced. The present new method of vulcanization of MCF rubber is effective enough that it is widely used in haptic sensors in robotics as well as in engineering applications. In the present report, we introduce its mechanism and the electric and dynamic characteristics as well as Piezo effect.

　Hardness and magnetic hysteresis loop measurements were performed in a partially die-quenched (DQ) steel plate, and the small steel pieces of spesimen with different cooling rate. The change in microstructre of the specimens were quantitatively characterised by electron backscattering diffraction (EBSD) measurement. A good correlation between hardness and coercivity was confirmed in both series of specimens, which is related to to the formation of martensite. This study demonstrates the plausibility of magnetic nondestructive evaluation of the hardness in DQ products, which improves the quality assurance of automobile components.

　To quench the forced vibration of the motor stator caused by the rotating distributed electromagnetic force, single mass is set on the stator which is supported by the two springs. Moreover, two Houde dampers are installed on the outside of the circular stator. The solutions of forced vibration are obtained by using the ring theory and the finite element method. The following were made clear; By setting an mass at the position of hoop of cos mode and setting spring supports at the positions of hoops of sin mode, those resonance frequencies are separated enough each other. As a result, the vibration amplitude of the stator becomes lower. Moreover, by setting two Houde dampers with the interval of hoop and node of the considered mode, the vibration of the stator is quenched over wide frequency region around the resonances. The characteristics of the results obtained by the ring theory coincide with those of the results obtained by the finite element method.

　Investigating the human body communication between a wearable device mounted on the human arm and a stationary equipment on or without the earth ground, we have reported the transmission characteristics and the electric field distributions around the human body and the stationary equipment on or without the earth ground. We have also shown that those characteristics and field distributions were different between the case with or without the earth ground. In this paper, the surface current distribution on the human body and the stationary equipment on or without the earth ground were numerically analyzed, and the relationship between the surface current distribution and the transmission characteristics were investigated and clarified.