Has anyone tried logging shock velocities? Sample rate ok?

Moderators: jlucas, RTUSA, kieran

blentz2
Posts: 34
Joined: Tue Aug 04, 2009 1:25 pm

shock sensors

Postby blentz2 » Thu Nov 24, 2011 2:52 am

What I have read is that for normal roll and pitch shocks move up to 4"/sec and for major bumps maybe 10"/sec. If so, at 100hz we're getting a sample every .040" of travel for roll and pitch and every .100 for bumps. Seems adequate enough to me.

Support

Postby Support » Thu Nov 24, 2011 10:29 am

Well... it's an interesting question!!

The main reason we are upgrading the DL1 to higher sample rates is to support users wanting to do shock/dampler analysis, and up until very recently I really thought that >100Hz was needed.

However I recently had an interesting meeting with one of our professional customers and long time fan of the DL1 - he told me they use the standard DL1 for lots of there suspension development. He was a very qualified/knowledgeable and senior chassis engineer at a very large OEM, heading up a group in their performance divison.... given he was far more qualified in the subject than myself, I've now changed my opinion to 100Hz is actaully enough for this work, although, faster is still preferable.

Kind regards,

Support

Bikey
Posts: 95
Joined: Fri Apr 29, 2011 6:05 am

Postby Bikey » Thu Nov 24, 2011 5:36 pm

This thread asserts that 500Mz is needed to avoid false interpretation:

http://forums.bimmerforums.com/forum/sh ... ?t=1532197

Support

Postby Support » Thu Nov 24, 2011 5:52 pm

I think typically think 200Hz+ is normally desireable, hence the upgrade to the DL1mk3 - however as I say we've got a large customer using 100Hz of the Dl1 and then playing it back into a full 7 post lift setup and optimising contact patch areas very sucessfully.

cguenther
Posts: 36
Joined: Sun Jan 25, 2009 11:12 pm

Postby cguenther » Sun Nov 27, 2011 6:26 pm

hi,

here is an example abozut logging shocks with 100Hz.

http://future-electronic.eu/images/stories/Projekte/Automotiv_Fahrwerkssimulation/FahrwerksanalyseLandy.pdf

best regards
carsten

Rob Stevens
Posts: 36
Joined: Sun Oct 31, 2010 9:36 am

Postby Rob Stevens » Sun Nov 27, 2011 6:48 pm

Great - May as well be in German ! :)

blentz2
Posts: 34
Joined: Tue Aug 04, 2009 1:25 pm

Postby blentz2 » Sun Dec 11, 2011 3:55 am

Here is a link with some data logged at different rates. Looks like 100hz should be fine based on this.

Image

automotion.co.nz
Posts: 6
Joined: Sat Nov 01, 2008 7:17 pm
Location: New Zealand
Contact:

Postby automotion.co.nz » Wed Feb 22, 2012 7:47 am

Can you post a screen shot without the graph points joined?

What sensors are you using?
Shake and Bake baby

audipower
Posts: 2
Joined: Fri May 01, 2015 8:08 pm

Postby audipower » Thu Jul 30, 2015 3:03 pm

Hello @all,

could anyone give me a hint how to get shock velocity calculated from damper travel?

I get readings from the linear sensor in mm, but my knowledge is not enough to do the right Settings for calculating the velocity.

I would be thankful for every help

osborni
Posts: 502
Joined: Fri Dec 07, 2007 9:08 pm
Location: USA, Michigan

Postby osborni » Tue Aug 04, 2015 1:53 am

Speed is the 1st derivative of displacement. Acceleration is the 2nd derivative.

http://www.dummies.com/how-to/content/h ... tion-.html

Differentiate displacement and you get speed.
Differentiate speed and you get acceleration.
BMW 2000 M Coupe


Return to “Sensor-related questions”

Who is online

Users browsing this forum: No registered users and 2 guests