By means of the phase-plane analysis, the author has performed a theoretical study of the discontinuous damping servomechanism devised by him in case where the torque saturation is taken into account. In this servomechanism the system damping ratio is changedfrom a small value to a large one by switching the relay discontinuously according to the switching function that depends upon the error, the error rate and the large damping ratio, so as to make the response time minimal and the overshoot zero for the step input. The conclusions obtained from the results of study may be summarized as follows. 1) It is possible to obtain the favourable transient response by determining the system parameter suitably. 2) It is possible to design a system whose transient response is approximate to the optimum relay servomechanism. It is a profit of this system not generate the “Chattering”. 3) In this system the “reticence” phenomenon occurs as in the linear switching relay servomechanism. However, this can be avoided by designing the system parameter suitably.

View full abstract

In contrast with the electrical servomechanisms, every element within the hydraulic servomechanism operates interfering with each other, so this makes impossible the precise treatment and design of the hydraulic servomechanisms only by the block diagram methods.
Therefore, the representation of the relations among the elements, say, servovlaves, piping, hydraulic motors, various loads, by the matrix and signal-flow diagrams makes it easy to calculate the transfer functions, the output and input impedance.
This paper presents the detailed dynamic relations existing in a force feedback type servovalve by the above methods, and its design criteria and the design procedure.
This paper constitutes a part of the study of high speed electro-hydraulic servomechanisms scheduled to follow hereafter.

View full abstract

A remote control system which controls automatically the angular motion of a heavy load in reply to the electrical signal from a director has studied theoretically and experimentally.
This servomechanism consists of a double-speed synchro circuit, a hydraulic stroke control mechanism and a hydraulic transmission. The transfer functions of each component are calculated, and the system characteristics are certified by experiments.
The features of this system are as follows:
(1) The electric circuits are simplified by using the differential synchro torque motor, because the synchro signals are directly transduced to the mechanical displacement of a pilot piston in the stroke control mechanism.
(2) The error corrector eliminates the velocity error between the director and the load for a ramp input. This device has a positive feedback loop and by this action the type of servomechanism changes from type 1 to type 2.

View full abstract