Mesured Acceleration as Input to ADAMS

[pefl99]

Dear Forum,

I have 5 sets of Data representing x,y,z acceleration at
Point _A and y,Z accelerations at Point_B.

Is there a way to use this data to simulate the reaction of a Mechanism to those Accelerations?

Thx
Martin

 

[GregLocock]

Yes. You can either build a spline with them, and use that as an excitation, or you can read in the file. The latter sounds more straightforward, but it is not immediately obvious how to do it.

You may have to double integrate them first, to give displacements.

Here's the relevant part of the adm file where I applied a time history of force to a model

! adams_view_name='SFORCE_1'
Sforce/1
, Translational
, I = 67
, J = 68
, Actiononly
, Function = INTERP(time,1,1)
!
!------------------------------ DATA STRUCTURES --------------------------------
!
! adams_view_name='SPLINE_1'
! adams_view_units='no_units'
Spline/1
, File = /simple/shudderwft.rsp
, Channel = 6
!
! adams_view_name='SFORCE_1_MEA_1'
Variable/1
, Function = SFORCE(1,0,1,0)
!
! adams_view_name='SFORCE_1_MEA_2'
Variable/2
, Function = SFORCE(1,0,2,0)


you'll be able to do the same with a MOTION statement.




Cheers

Greg Locock

 

[pefl99]

Hi Greg,

thx for your reply!

But I'm still a little *g* bit lost.

Duoble integrating the data is VERRY errorenous.
and as I'm quite new to this game what is an adm file what do I do with it where does it integrate into the simulation ...

I started out with Dynamic Designer but was able to persuade the company to go for the full range. Now I got the toy, but I'm overhelmed by it's possibilties.

Sorry to bother you or anybody else who is willing to support a bloody rooky.

cheers

Martin


and by the way forgive me my english.

 

[GregLocock]

Which package are you using?

Double integrating is not erroneous, you are going to trust ADAMS to do it anyway! However according to this velocity is better.

http://support.adams.com/kb/faq.asp?ID=kb9752.html

Note that you can only apply a MOTION to a joint.

Have you done all the ADAMS/View tutorials? You need to.

The adm file is a list of all the model statements that gets sent to the Solver. As such it is very good debugging tool, for the more integrated products, which do not explicitly create an adm file.


As a first step do the following tutorial

http://support.adams.com/kb/faq.asp?ID=kb8708.html

then convert it so that the slider motion is defined by one of your drive files.


Cheers

Greg Locock

 

[GregLocock]

This example does what you are trying to do

http://support.adams.com/kb/faq.asp?ID=kb10513.html

for a simple case

Cheers

Greg Locock

 

[pefl99]

Hi Greg,

thx for your advise!

I'm almost there

Martin

 

[ubrben]

Greg I'm sure you can add an acceleration directly to a joint. In the general motion dialog box you can select the function to be an acceleration as a function of time and you can do it directly in command language using something like this:

var set var=.EH101_MMI_AC.MOTION_deck.t1_type int=3

Ben