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Recently, robot research that coexists with people and is helpful for them has been done. To coexist with people, it is necessary for robots to realize the same flexible motion as people. To grasp, a robot hand is required to control position accurately and treat the object flexibly. Additionally, when taking care of the elderly and patients, who are a typical example of personal service, safety and pliability are required because of much contact with people. Therefore, it is important to choose the proper materials, mechanics, drive systems, and control systems. Then, we propose pneumatic actuators as source of power of robot hand. But, to generate power, a past actuator needs a high compressed air. Then, in this research, a pneumatic actuator driven by low-pressure and low-volume is presented that is originally developed for driving a robot hand that works flexibly and is safer on the assumption of people contact. And this actuator is designed to get enough force to drive the hand in low-pressure. Because of the linear characteristics, this actuator can be easily controlled. And, the force control system that uses this actuator is constructed and the control performance to apply to the robot hand is examined. At the same time, five fingered robot hand using the pneumatic actuators is shown, and we show that the robot hand can do the same operation as man.

This paper presents a non-metallic and light robot hand that uses balloon-type pneumatic actuators that we developed. Recently, there has been a lot of research into robot coexisting with people and helping them. Such robots must be proven safe for contact with people. The drive system of our proposed robot hand uses balloon-type pneumatic actuators that we originally developed in consideration of the safety measures required for human contact. The results of test on the characteristics of the pneumatic actuator proved that it is possible to drive a robot hand and create enough generated force to grasp objects using lower inner pressure and lower air volume. Moreover, a model the same size as a human hand can be made without a big air compressor, we also consider the applications of such prosthetic hands.

A methylamine dehydrogenase was purified to homogeneity from Pseudomonas AM1 and obtained in crystalline form. It was found to be a subunit enzyme composed of two kinds of subunit, light and heavy. These two subunits were isolated by Sephadex G-100 gel chromatography after incubation of the enzyme with guanidine hydrochloride. Molecular weights of 13,000 daltons for the light subunit and 40,000 daltons for the heavy subunit were estimated by SDS-polyacrylamide gel electrophoresis, and the molecular weight of the native enzyme was found to be 105,000 daltons by Sephadex G-200 gel chromatography. The enzyme and its subunits were also analyzed for amino acid composition, isoelectric point, and absorption fluorescence, and CD spectra, as well as for the effects of pH, thermal treatment, and guanidine hydrochloride treatment. Both the subunits were absolutely required for enzymatic activity, either subunit alone being inactive. It could be deduced from the absorption and fluorescence spectra of the subunits that the prosthetic group of the enzyme was bound solely to the light subunit. These results suggest that the enzyme is a subunit enzyme similar to that of Pseudomonas sp. J, of the alpha2beta2 type.

Hybridization reactions were carried out in vitro between the light and heavy subunits of two methylamine dehydrogenases obtained from Methylomonas J (formerly Pseudomonas sp. J) and Pseudomonas AM1. Enzymatic activity was restored with a combination of L3(MW: 13,000) and HA(MW: 40,000) but not with LA(MW: 13,000) and HJ(NW: 40,000). This active hybrid enzyme was isolated with a Sephadex G-150 column after incubation of LJ and HA. Its molecular weight was nearly identical to that of the two native enzymes (MW: 105,000). The electrophoretic pattern of proteins cross-linked by dimethyl suberimidate showed the formation of a tetrameric structure. Its absorption spectrum was similar to that of the native enzymes. The specific activity was 4.3 and the substrate specificity resembled that of the Methylomonas J enzyme rather than that of the Pseudomonas AM1 enzyme. Michaelis constants were 290 microM for methylamine and 14 microM for phenazine methosulfate. The circular dichroism spectrum and thermal stability resembled those of the Pseudomonas AM1 enzyme. No appreciable amount of an inactive hybrid enzyme was formed in the reaction between LA and HJ, there being neither restoration of the enzymatic activity nor formation of cross-linked tetrameric proteins with dimethyl suberimidate. Hybridization of LJ and HA was further confirmed by the appearance of three enzymatic active bands on a gel after electrophoresis of an incubation mixture of LJ, HJ, and HA. The results are consistent with a previous observation; the two methylamine dehydrogenases from either obligate of facultative metaylotrophs are the alpha 2 beta 2-type and homologous enzymes. It is also suggested that substrate specificity and catalytic activity are directed by the light subunit, and binding affinity of the substrate to the active site, electrophoretic mobility, and thermal stability of the enzyme are endowed by the heavy subunit.