Subject: RE: TAKENAKA
Date: Sun, 23 Jan 2000 02:47:05 -0600
From: "Imafuku, Nobuhiro" <Nobuhiro.Imafuku@mts.com>
To: "Rood, Omar" <Omar.Rood@mts.com>, "Larson, Rod" <Rod.Larson@mts.com>
CC: "Otsuka, Yutaka" <Yutaka.Otsuka@mts.com>

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 gLOWh 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 gLOWh pressure and then
> gHIGHh 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 gLOWh 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 gLOWh 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
>
