We clarified by numerical analysis with the effect of mass concentration and electrode gap on the steady torque characteristics and the velocity distribution of a rotating disk in ERF under D.C. electric field. The analysis is based on mechanical dynamic model. By comparison with experimental results of torque characteristics, the efficacy of prediction by this numerical analysis was also investigated.

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This paper concerns the friction force of a pneumatic cylinder with a metal seal of labyrinth structure as the piston seal. One major problem in the most widely rubber-sealed pneumatic cylinder used is that friction force greatly affects its performance because the driving force is relatively low, specifically when performing tracking control of the piston to an arbitrary position. On the other hand, a labyrinth-sealed pneumatic cylinder, which was developed for the purpose of reducing friction force, is capable of realizing quick and precise operation. In addition, it excels in terms of resistance to heat and wear, although a labyrinth seal causes deterioration of the damping capacity of a system due to low friction and air leakage from clearance at the seal. The labyrinth-sealed pneumatic cylinder has received little attention because of its disadvantages and so its dynamic properties are not elucidated enough for many practical applications.
This paper, in the first place, conducts measurements in order to investigate the behavior of the dynamic and static friction forces acting on the sliding parts in a labyrinth-sealed pneumatic cylinder, as well as its performance at low speed, from the viewpoint of stick-slip occurrence. Comparing with a rubber-sealed pneumatic cylinder, its fundamental disposition is examined and grasped empirically. Furthermore, applying hydrodynamic lubrication theory to the labyrinth seal, the pressure of the lubricant film formed on the seal surface is numerically calculated. The dynamic friction force generated by the lubricant film is estimated from the pressure distribution obtained. The numerical results are verified by referring to the measurement results, showing that the dynamic friction force can be approximately computed by this numerical approach.

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The characteristics of pneumatic actuators vary according to the position of pistons due to the compressibility of air. We adopted a scheduled controller to eliminate the effect of variation of cylinder parameters. We designed the controller by making use of LMI (Linear Matrix Inequality). Experimental results demonstrate the effectiveness of this control systems.

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In this study, we deal with a bilateral master-slave system composed of a pneumatic force-display, as the master, and a hydraulic servo system, as the slave. In such systems, the master, that is the force display, has to play two roles : first as a reference input device to the slave and secondly as a force display device. The first purpose of this study is to develop a pneumatic force-display which consists of a pneumatic servo system. For this purpose, it was necessary to solve a problem called back-drivability which attributes to pneumatic servo systems. The second purpose of this study is to investigate the compatibility of thus developed force display when applied to some representative methods of bilateral master-slave control systems in conventional use. In experiments for confirming compatibility of the force display, the sensibility of load forces is estimated based on the master-slave system in which a spring is equipped as a load. Consequently, it was confirmed that the developed force display would be applicable to conventional methods of bilateral master-slave systems.

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