A unique flowmeter has been newly developed based on the principle that the distribution of the pressure difference acted on a stationary tapered body, which is eccentrically installed parallel to a fluid line. This resulted in generation of torque around the center of the tapped bodies, and a voltage output as proportional to the flow rate. The proposed flowmeter features a simple structure, low pressure-loss and no moving parts. In this paper, analytical theory on the two-dimensional viscous flow is conducted in respect to two kinds of the flowmeter having rectangular and circular configurations, respectively. Consequently, the rectangular type of the flowmeter is employed due to high flow rate versus torque gain. The design specification and parameters are determined by analytical solutions. Finally, the theoretical static characteristics of the flow rate versus torque and pressure loss are experimentally verified by changing the fluid viscosity and design parameters.

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A novel actuator with built-in compound control function of displacement and thrust is proposed, to realize simplicity and miniaturization of a complicated hydraulic system that requires displacement and thrust control. This actuator is a kind of compact hydraulic cylinder system, which consists of a stepping motor, a control valve with a spool and a slide sleeve, a hydraulic cylinder and a mechanical feedback mechanism. In the proposed actuator, with a mechanical displacement feedback and a mechanical pressure feedback, displacement and thrust control can be realized. The basic characteristics of this actuator in the compound control of displacement and thrust are investigated by mathematical model analysis. Through the preliminary experiments,it is confirmed that the actuator is very effective in the compound control of displacement and thrust. Finally, it is shown that the precision of this actuator can be improved by introducing a dither signal.

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