Subject: RE: TAKENAKA
Date: Thu, 20 Jan 2000 22:42:49 -0600
From: "Rood, Omar" <Omar.Rood@mts.com>
To: "Imafuku, Nobuhiro" <Nobuhiro.Imafuku@mts.com>, "Larson, Rod"
     <Rod.Larson@mts.com>, "Smith, Jim" <Jim.Smith@mts.com>
CC: "Katabami, Yoshihiro" <Yoshihiro.Katabami@mts.com>, "Otsuka, Yutaka"
     <Yutaka.Otsuka@mts.com>

Hello Fuku & Jim,
Rod is in Hong Kong and I am in Dalian.  Jim, please get and ship the 2
accumulators needed (see below)

Fuku, did this problem just start now, you were running last week no
problem, correct?

Omar

> -----Original Message-----
> From: Imafuku, Nobuhiro
> Sent: Thursday, January 20, 2000 6:53 PM
> To:   Rood, Omar; Larson, Rod
> Cc:   Katabami, Yoshihiro; Otsuka, Yutaka
> Subject:      TAKENAKA
>
> Hello, OMAR & ROD san.
>
> 1.    We have a big trouble. When we apply "LOW" pressure, actuator
> suddenly goes unstable (oscillation problem) but this happens only
> couple seconds (see enclosed Oscillation Data file) and goes stable.
> We check follows (we always enable limit, so that table and actuator
> have no damage). Once we apply "LOW" pressure and then "HIGH"
> pressure, we do NOT have any oscillation problem until hydraulic off.
> We assume this is caused by air like NIED prototype table but we are
> NOT sure. Please advise how check this trouble more and please send
> two slow turn on accumulators for HSM urgently.
> 1)    At first, we check HSM and we found two slow turn on
> accumulators for 100 ton actuator are broken (we can NOT charge N2
> gas).
> 2)    We check servo valve with pilot pressure only and maximum spool
> position is set about +/- 2V. Normally, we set this value about +/- 6
> - +/- 8 V. We think this value is quite low. Is this normal value if
> we use TestStar IIs ?
> 3)    We apply 210 kg/cm^2 pressure and push "LOW" using two HSM.
> Actuator suddenly goes unstable and stops because exceeding limit (we
> have no damage on table and actuator due to enable limit). At this
> time, displacement gain is 1 and control mode is displacement.
> 4)    We use two HSM and apply 50 kg/cm^2 pressure. When we check at
> displacement gain 1 on displacement control mode, actuator goes
> unstable. Then we decrease gain step by step, actuator oscillation
> stops at displacement gain 0.07 but actuator slightly moves.
> 5)    We use two HSM and apply 210 kg/cm^2 pressure. Actuator does NOT
> suddenly unstable but actuator slowly moves and stops about middle
> position.
> 6)    Then, we change acceleration control mode and tune system (we
> still have same problem when we apply "LOW" pressure).
> 2. We are possible to connect all hoses now for 100 ton actuator (two
> HSM sit actuator right side and other two HSM sit actuator left side).
> When we apply pressure, we have too much flow and high pressure
> sometimes does not reach 210 kg/cm^2. If we ignore low pressure
> adjustment, this flow stops. Do you have any idea to adjust four HSM
> working correctly ? 50 ton actuator looks OK.
>
> I tried to send this mail yesterday but our server was down and I
> could NOT send. Please reply by return.
>
>  << File: Oscillation Data.xls >>
>
> REGARDS     FUKU
>
