Subject: RE: TAKENAKA
Date: Sun, 23 Jan 2000 06:42:45 -0600
From: "Rood, Omar" <Omar.Rood@mts.com>
To: "Imafuku, Nobuhiro" <Nobuhiro.Imafuku@mts.com>, "Larson, Rod"
     <Rod.Larson@mts.com>
CC: "Otsuka, Yutaka" <Yutaka.Otsuka@mts.com>

Fuku,
What you describe can only happen if you don't get pilot pressure to the
servovalves before main pressure, if pilot pressure and main pressure
come on at the same time, then the servovalve may be hard over so this
only can be done at very low pressure.

Please check the timing of your pilot pressure.
Omar

> -----Original Message-----
> From: Imafuku, Nobuhiro
> Sent: Sunday, January 23, 2000 2:47 AM
> To:   Rood, Omar; Larson, Rod
> Cc:   Otsuka, Yutaka
> Subject:      RE: TAKENAKA
>
> Hello, OMAR & ROD san.
>
> 1.    We have no trouble to connect hoses, so we connect all hoses and
> apply high pressure without table at displacement control mode
> (displacement gain is 1). Also, we have a trouble to connect hoses, so
> we connect half hoses and apply high pressure without table at
> displacement control mode (displacement gain is 1). At this time, both
> actuators work OK.
> 2.    We connect both actuators to table and apply high pressure
> finally. At first, we apply high pressure to 50 ton actuator and we
> have no trouble. Then, we apply high pressure to 100 ton actuator and
> we have a little trouble. We think this trouble is caused by valve
> driver, so that we replace valve driver (we swap valve driver A and
> B). TAKENAKA prepare slide bearing for swivel head and mounting
> fixture for actuator, so actuator never swings when we operate single
> axis. Note that we never operate both axes simultaneously.
> 3.    When we proceed 50 ton actuator tests, when we run KOBE
> earthquake with AIC control, actuator suddenly extend and retract,
> then table base slide bearing is broken.
> 4.    We try to connect all hoses on 100 ton actuator and we can
> connect all hoses temporarily. When we apply pressure to 100 ton
> actuator, we have an oscillation problem. Also, we apply pressure 50
> ton actuator, we have same problem.
> If we apply pressure at very low pressure (30 - 50 kg/cm^2) and very
> low displacement gain (about 0.1), actuator still moves slowly, but
> this movement does NOT damage specimen. So, I explain TAKENAKA and
> TAKENAKA will start test next week with YUTAKA.
>
> REGARDS     FUKU
>
>
>       -----Original Message-----
>       From:   Rood, Omar
>       Sent:   Friday, January 21, 2000 1:43 PM
>       To:     Imafuku, Nobuhiro; Larson, Rod; Smith, Jim
>       Cc:     Katabami, Yoshihiro; Otsuka, Yutaka
>       Subject:        RE: TAKENAKA
>
>       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
>
