BISRA GAGE METER plate thickness control method is currently main stream in rolling mill hydraulic screw down apparatus. By this method, precise plate thickness control was established.
But, this method is known to worsen plate thickness accuracy by amplification of roll eccentricity effect which is an inner disturbance in hydraulic servo loop of screw down control.
For this situation, at present, the method of fourier analysis of roll separating force to detect roll eccentricity vector is attempted.
Despite this, the control equipment is said to be apt to become complicated regarding at gain and phase adjustment for analog outputting.
We devised a new correlation method for roll eccentricity detection, consideringthat roll eccentricity has periodic signal synchronization with roll revolution, in contrast with input plate thickness variation that is random in nature.
Further, both digital and analog methods of correlation analysis are compared. Latter method which uses SIN and COS two reference signals is proven to be superior to the former.
As roll eccentricity control method (elimination method) two types are studied.
The first is command method, and the second is feedback method which lessens rolling mill stiffness by a control scheme, for roll eccentricity frequency only.
The latter feedback method is proven to have sufficient control ability.
By these studies, an economical analog correlation type roll eccentricity eliminator with high performance was developed.

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In the previous report, the mill modulus soft control for the roll eccentricity frequency was shown to be effective for roll eccentricity control.
This time, so as to study the control effect of the Bisra Gage Meter which is composed of a hydraulic servo loop for complicated roll eccentricity waveform, the author carried out small mechanical roll eccentricity model test.
With this model, the roll eccentricity effect was reduced to 1/5 to allow for a simple sinusoidal eccentricity waveform.
However, due to the complicated real roll eccentricity waveform which shows a beat resulting from the difference between upper and lower backup roll diameter, 6 correlation filters were required corresponding to each 3rd harmonic and roll eccentricity effect were reduced to 1/3.

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In this study, the parallel link consists of three electrohydraulic servo cylinders which can realize arbitrary motion in a plane having a large output force and torque by a simple structure. Applying the compliance control method to this mechanism, it is possible to control the three-dimensional position of the end effector under a free motion condition and the output force and torque under a blocked motion condition, which are proportional to the position error signals in each direction. Applying the state feedback control method to this system, it is possible to realize desired dynamic characteristics of the displacement control subsystem and the compliance control subsystem independently without their interaction. The static and dynamic characteristics of the system are shown experimentally.

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With all the advantages over other actuators, such as high power/weight ratio and intrinsic compliance, the use of a pneumatic cylinder is limited to simple tasks at present. This is because the pneumatic cylinder has stick-slip motions at low velocities caused by a nonlinear friction force due to the mechanical sealing parts.
However, electro-rheological fluid (ERF) has lately been attracting a great deal of attention as a new functional material. The ERF can increase the shearing stress when subjected to an electric field. Therefore, by making use of this characteristic, a functional damping device capable of controlling the damping force by controlling electric signal can be developed.
This paper centers on a compensatory method capable of achieving a constant, slow motion pneumatic cylinder by using an ERF damper. This method aims to overcome any decrease in the nonlinear friction force, i. e., the friction force against the increase in piston velocity, which may cause stick-slip motion. As a result of this study, this compensatory method was proven to be applicable to the pneumatic cylinders in a wide range of velocity controls.

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This paper deals with noise reduction of a balanced vane pump which is used in power steering system based on a simulation technique.
To ensure passenger car riding comfort, it is important to reduce the noise and vibration levels of the hydraulic pumps used in them. From the viewpoint of car energy consumption, a weight reduction of automobile parts and components is becoming an important issue. The weight reduction, however, leads to an insufficiency in stiffness of the parts and components and may cause a lessening of the dynamic characteristics of those parts and components.
To develop a quiet hydraulic pump as an automobile part, the internal pressure fluctuation must be reduced. To solve this problem, simulation techniques are usually needed. Conventional simulation techniques, however, do not take into account the effect of the stiffness of the parts and components, and accordingly, the simulation results are not accurate enough.
In this study, the effect of the cam deformation on the internal pressure of a vane pump has been investigated both theoretically and experimentally.
The advanced simulation technique to predict internal pressure was developed, taking in consideration cam deformation, and noise reduction of 2-4dB could be achieved through the design application of this technique.

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