In this paper, a combined control method using a two-degree-of-freedom controller and a neural network compensator is applied for trajectory control of a pneumatic cylinder. The two-degree-of-freedom controller consists of the I-PD controller,Smith's time delay compensator and disturbance compensator. The design procedure is essentially based on partial model matching which offers a reasonable way to simplify the design and controller configuration under disturbance rejection. In addition, a neural network compensator is used to compensate for modeling errors due to the non-linearity of the plant, and friction between cylinder and piston. Computer simulations and experiments of the trajectory control were carried out under various conditions. From the results summarized below, the effectiveness of the proposed control scheme could be confirmed :
(1) Excellent reference tracking performance was obtained by adding the neural network compensator.
(2) Excellent control performance for step disturbance was obtained.

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Wearable robots actuated by air pressure require small air pressure generation system. Miniaturization of air pressure generation system using a pump is limited by size of the pump when the system requires compressing or exhausting air quickly. If the system requires controlling the air pressure quickly but not frequently, it is possible to reduce the weight of the system by controlling air pressure using a tank that is pressurized or compressed by a small pump. However the capacity of the tank must be enough large for the control object especially in case of vacuuming. This paper shows that the system can be miniaturized by pressurizing or decompressing an object in stages using two or more tanks. The theoretical analysis of the relation between the number of tanks and the generative air pressure shows that the number of tanks is optimized to the size and weight of the system. The time to generate an air pressure in stages is estimated by the number of tanks. These analyses were confirmed by experiments using vacuuming systems with different number of tanks. This paper also shows that reuse of the air pressure in tanks is performed effectively in this method. The relation between the number of tanks and the effectiveness of the reuse of the air pressure is described.

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The cataract is a disease of that crystalline lenses get opacified because of aging or other causes. In case of serious cataract, opacified lenses must be replaced with artificial lenses. The PEA (PhacoEmulsification Aspiration) is, in recent years, a major technique for removing opacified lenses. There is, however, a problem called as surge phenomenon still to be solved in the PEA. The surge phenomenon is that an intracameral pressure accidentally falls down to an extreme and this would invite a possibility of blindness in the worst case. Though there exist some passive countermeasures against it, but not enough to secure the safety of surgical operation. This paper describes how to control an intracameral pressure by down-seized gear pump and a modern control theory. We could simulate a surge phenomenon in our modeled eye. Having designed a SAC (Simple Adaptive Control) servo system, we succeeded to minimize the surge pressure to an allowable level.

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