Free SLA Suspension Kinematics Program |
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swolfe
Bolt Sorter One and done Joined: Mar/26/2011 Status: Offline Points: 1 |
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Posted: Mar/26/2011 at 9:27pm |
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MOD NOTE: See this post for a zip file of the completed MATLAB file with GUI.
I don't do Baja (I'm involved with a different project), but last year I wrote an SLA suspension kinematics program that I thought might be helpful for some SAE Baja (or FSAE) teams. It's free, under the GNU Public License. Unfortunately, I do not have a place to host the file. Zipped, with the user's guide, it's only 185 kb. If anyone wants a copy, send me an email. If anyone is willing to host it, that would be even better. Now, if you already use Lotus or ADAMS or something, this program is not for you. It's not nearly that powerful. It's pretty simplistic, it only calculates parameters for a quarter of the car, and only for SLA suspensions. This program is designed for someone who knows the very basics of MATLAB and nothing else. Of course, you need some vehicle dynamics knowledge to make use of the results. It might be helpful, it might be a pain in your ass, I just thought I would offer it up in case anyone is interested. Program inputs (all at ride height): - Upper A-arm ball joint locations - Lower A-arm ball joint locations - Wheel center & middle of tire @ ground plane locations - Tie rod inner & outer ball joint locations - Suspension travel - Brake bias - Brake type (inboard or outboard) - Suspension type (front or rear) - Wheelbase length - CG height (The last 5 are only used for calculating anti- features, assuming rear drive) Program outputs: Scalars - Caster angle - (Mechanical) Trail - Kingpin angle - Scrub - Spindle length Plots - Suspension position throughout travel (front view) - Suspension positions in jounce (3D view) - Camber curve - Bump steer curve - Roll center height (assumes symmetric jounce/rebound) - Roll center location during cornering (assumes opposite motion on opposite side of car) - Front anti-dive (if applicable) - Rear anti-squat (if applicable) - Rear anti-lift (if applicable) The kinematics are calculated numerically. I believe the errors in calculated positions to be on the order of a few thousandths, but the precision can be adjusted by the user. Edited by Mod Squad - Dec/31/2012 at 2:19pm |
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RonGeorge
Welding Master Joined: Apr/17/2010 Location: Indiana Status: Offline Points: 286 |
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Nice work! Bump steer, scrub, travel etc are very applicable to off-road. The source code might be doing a lot of vector transformations to cycle the input model. Now where are your kinematic equations sourced from, a dynamics text?
While Baja SAE is about designing an ATV, I have debated with myself about the true value of knowing anti-features in off-road scenario, given that our low pressure tires as well as terrain are not rigid, but has give - elasticity, plasticity - provided with the fact that we have 9-9.5 HP. So I don't know if straight line acceleration potential will even pass +/- 0.5g for most teams. But it might come in handy if the car is sitting really low and you want to figure out the worst case clearance between bottom of the car and the ground. |
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-Ron George
Systems Engineer (Cummins Turbo) |
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shahpratik
Bolt Sorter Joined: Jul/06/2011 Status: Offline Points: 1 |
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Can you send your software program for suspension to my email id: shahpratik3@yahoo.com
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chicostate
Bolt Sorter Joined: Jul/27/2011 Location: United States Status: Offline Points: 1 |
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Hey would you mind sending your program my way?
michaelman5119@gmail.com
Thanks Mike |
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p.lewis
Welding Master Joined: Oct/05/2009 Location: Greater Detroit Status: Offline Points: 296 |
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I know I'm replying to an old post, but I just read this and had to comment.
Anti-feature calculations are valuable for every longitudinal thrust on the wheel, not just braking and accelerating. Think about that for a while and you'll begin to imagine why knowing your anti's is important in different ways for off-road than for on-road design.
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University of Rochester Alum
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klusaebaja
Bolt Sorter Joined: Jul/09/2011 Status: Offline Points: 11 |
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please send it to bharathallu@gmail.com cheers!
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UBCBaja2011
Bolt Sorter Joined: Aug/10/2011 Location: Vancouver Status: Offline Points: 1 |
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Hi could you also send it to jay.haer@gmail.com
Thanks
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Yony
Bolt Sorter Joined: Aug/14/2011 Status: Offline Points: 1 |
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hi dear....your program is a very useful tool to get an idea how to do similar modelling for other types of suspension kinematics....it will be a great help, if you tell me, where i can download the program...
Thanx a lot!! |
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Bettner12
Welding Master Joined: Jan/24/2011 Location: Hanover, Pa Status: Offline Points: 239 |
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bettner12@gmail.com
thanks!
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Penn College of Technology Alumni
Maryland 2018 Organizer |
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sandres913
Welding Master Joined: Aug/17/2011 Status: Offline Points: 216 |
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ska913@gmail.com
Thank you in advance!! |
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Trial&Error
Bolt Sorter Joined: Aug/18/2011 Status: Offline Points: 1 |
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A copy to:
MechaniX_034@hotmail.com please! Thanks for that Edited by Trial&Error - Aug/18/2011 at 8:45am |
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"When we said plumbing, we did NOT mean to put a cistern in the car!"
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abenn
Milling Master Joined: Mar/15/2010 Location: Boston, MA Status: Offline Points: 70 |
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could you please send a copy to andrewsbenn@gmail.com
thanks!
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Andy Benn
Northeastern University Baja SAE http://www.facebook.com/nubaja http://www.numotorsports.com |
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teamsamra
Bolt Sorter Joined: Aug/13/2011 Location: India Status: Offline Points: 3 |
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Could you please send a copy to k.vignesh.krish@gmail.com
Thanks!!
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OctoberSky
Welding Master Joined: May/20/2009 Location: Los Angeles Status: Offline Points: 123 |
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Can you send a copy to anthonygambardella@gmail.com? Thanks!
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UCLA Racing
2010-2012 Captain "we'll never win mini baja" -Cheddar |
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p.lewis
Welding Master Joined: Oct/05/2009 Location: Greater Detroit Status: Offline Points: 296 |
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Could somebody please upload a copy of this on the forum. I'm just saying... then anybody could download it.
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University of Rochester Alum
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Laxtondt
Bolt Sorter Joined: Jun/30/2011 Status: Offline Points: 26 |
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Now that would just make too much sense.
or even a link to it stored somewhere else would work
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Tyrell Laxton
TTU Baja (guy with the hair) www.ttubaja.com |
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collinskl1
Baja Godfather Joined: Jan/21/2009 Location: Saginaw, MI Status: Offline Points: 1056 |
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I'm all for sharing knowledge... so I don't want this to come out the wrong way.
Developing your own simple program (excel, matlab, etc.) to do this stuff is not hard at all. If I could do it, anyone can haha! I know TTU has one, I had one, and I can promise you that by spending the time to study your vehicle dynamics books and generate the formulas you'll increase your knowledge of the system wayyy more than just downloading a freebie. I mean that's why you're doing baja right? To learn? Yes, values and numbers and DATA are really cool and fun to spout off, but if you went to the work to completely understand them and become intimately involved with the calculations and your design... that's what a design judge likes to see.
So again, not knocking this program or any of the people asking to see it, but I think it should be used in conjunction with some actual thought of your own.
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Kyle Collins
Lipscomb University Alumni 2x Project Manager Nexteer Automotive Product Engineer, Electronic Power Steering ... and the 8th simple machine: a bigger hammer. |
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OctoberSky
Welding Master Joined: May/20/2009 Location: Los Angeles Status: Offline Points: 123 |
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I fully agree that the numbers are useless unless you know what they mean...but honestly, writing a matlab/other code to solve a huge number of vector calculations that boil down to simple mechanics seems like a waste of time unless you are doing it for a CS class or money (or you like coding). The readily available programs work very well, are user friendly, solve quickly, and still provide numbers that are completely useless unless you know what they mean.
For me, it's more important to know how to properly use tools rather than make my own. I'd rather spend time programming calculators that I can't get for free/cheap such as braking force, drivetrain reduction sizing and torque, gear stress calculation, compressive/buckling strength in suspension members and tie rods, etc. Then again, if you are designing an innovative suspension that isn't one of the presets in these programs, then I think it would be appropriate to analyze it on your own. In the words of one of my favorite professors, a lazy engineer is an efficient engineer.
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UCLA Racing
2010-2012 Captain "we'll never win mini baja" -Cheddar |
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CLReedy21
Baja Godfather Joined: Nov/30/2008 Location: Marysville, OH Status: Offline Points: 736 |
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The program I created is a simple one that takes spring rates, motion ratios, track widths, etc and calculates wheel rates and roll stiffness values.
I made it in excel in an afternoon. In this particular situation it helped a bunch because it revealed some of the hidden interactions between the different parameters that affect the final values. BTW this is a dead thread. I don't think this guy ever came back to the forums. |
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-Chris Reedy
TTU Alumni Fourwheeler Drawer "Quick with the hammer, slow with the brain." |
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collinskl1
Baja Godfather Joined: Jan/21/2009 Location: Saginaw, MI Status: Offline Points: 1056 |
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Excel was my weapon of choice too... I'm pretty sure you can run the world with an excel sheet or two. F it ever becomes self aware we're all screwed. Next gen MS Office = skynet im pretty sure.
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Kyle Collins
Lipscomb University Alumni 2x Project Manager Nexteer Automotive Product Engineer, Electronic Power Steering ... and the 8th simple machine: a bigger hammer. |
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DazedandConfuzed
Bolt Sorter Joined: Sep/09/2011 Location: Birmingham Al Status: Offline Points: 1 |
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If possible, can you send me this program?
I would appreciate it
illpin37@uab.edu
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enuf27
Bolt Sorter Joined: Sep/14/2011 Status: Offline Points: 1 |
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Edited by enuf27 - Sep/15/2011 at 10:56pm |
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Brent
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Bettner12
Welding Master Joined: Jan/24/2011 Location: Hanover, Pa Status: Offline Points: 239 |
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Okay, so has anyone actually gotten the program? or did we get trolled by someone phishing for email addresses?
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Penn College of Technology Alumni
Maryland 2018 Organizer |
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Nick914
Organizer Joined: Jun/16/2010 Location: U Laval Status: Offline Points: 256 |
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The guy actually visited the forum for the last time when he posted.
Maybe you could check his profile and send him an email (he's got an adress you can see)
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Nicholas Lefebvre
Universite Laval |
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CLReedy21
Baja Godfather Joined: Nov/30/2008 Location: Marysville, OH Status: Offline Points: 736 |
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I sent him a PM after his initial post but never received any kind of response. Like Nick said maybe a direct email will work. Clinton, I nominate you. Go. |
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-Chris Reedy
TTU Alumni Fourwheeler Drawer "Quick with the hammer, slow with the brain." |
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borssate
Bolt Sorter Cain't read good! Joined: Sep/26/2011 Location: Brazil Status: Offline Points: 1 |
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dcarrero
Bolt Sorter Cain't read good! Joined: Aug/23/2011 Status: Offline Points: 1 |
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Hi can you send me a copy to davidyo87@hotmail.com Thanks
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collinskl1
Baja Godfather Joined: Jan/21/2009 Location: Saginaw, MI Status: Offline Points: 1056 |
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Reading is so hard sometimes...
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Kyle Collins
Lipscomb University Alumni 2x Project Manager Nexteer Automotive Product Engineer, Electronic Power Steering ... and the 8th simple machine: a bigger hammer. |
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Rob71zilla
Welding Master Joined: Feb/09/2009 Location: Utica, NY Status: Offline Points: 324 |
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/thread.
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Robbie
Former Team Captain SUNY Institute of Technology Current Engineer for Remington Arms A Redline a day keeps the carbon away. |
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Pride of the Dakotas
Bolt Sorter Cain't read good! Joined: Oct/19/2011 Status: Offline Points: 1 |
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Can you send a copy to daniel.towle@my.ndsu.edu?
Trying to find a good suspension analysis software One that's preferably user friendly
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tp
Welding Master Joined: Mar/31/2009 Location: Corvallis, OR Status: Offline Points: 348 |
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Not to derail this one, but I am absolutely in love with OptimumK. They have a pretty hefty student discount, it's extremely user friendly, it can analyze more parameters than you ever realized existed and either import or export points to and from your CAD model. Just something to think about....
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-Tom
Oregon State BajaSAE Team Captain |
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jeiB
Baja Godfather Joined: Jul/17/2009 Location: Montreal Status: Offline Points: 604 |
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May help some people here
http://tinyurl.com/3exdvmc |
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Jeremie B.
McGill Baja Racing 2009-2011 Captain minibaja.mcgill.ca |
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OMARZIANE
Bolt Sorter Cain't read good! Joined: Nov/30/2011 Status: Offline Points: 1 |
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Hi,
Thanks for the great work and for offering it to everyone. I'll really would apreciate if you send me a copy to "omar.ziane@formulauem.es" Thanks Omar ZIANE Formulauem team (European University of Madrid) Suspension team Manager
Edited by OMARZIANE - Nov/30/2011 at 10:07am |
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CLReedy21
Baja Godfather Joined: Nov/30/2008 Location: Marysville, OH Status: Offline Points: 736 |
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THIS THREAD IS DEAD. THERE IS NO SOFTWARE. THIS GUY POSTED THIS THEN NEVER CAME BACK. LET IT DIE ALREADY.
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-Chris Reedy
TTU Alumni Fourwheeler Drawer "Quick with the hammer, slow with the brain." |
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collinskl1
Baja Godfather Joined: Jan/21/2009 Location: Saginaw, MI Status: Offline Points: 1056 |
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Lock? |
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Kyle Collins
Lipscomb University Alumni 2x Project Manager Nexteer Automotive Product Engineer, Electronic Power Steering ... and the 8th simple machine: a bigger hammer. |
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Mod Squad
Welding Master Mutant Enforcer Joined: Oct/19/2010 Status: Offline Points: 200 |
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Quite an interesting thread.
Guy creates FREE suspension kinematics program.
Guy posts about said program in Baja SAE forum.
Guy claims he doesn't have anywhere to host the 185kB file. (Users get 20MB of storage space here...)
One hour. fifty three minutes later, guy posts same thing on FSAE.com.
Guy never signs into either forum again, even though his profile is set up to send him emails of replies to his thread.
The odd thing is guy exists, so it isn't a prank.
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Upon further internet sleuthing. I have found the program. It is called SLASIM. It is Mr. Wolfe's thesis. https://kb.osu.edu/dspace/handle/1811/45363?mode=full
The program runs in Matlab. The basic source code is in Appendix A. Looks like the GUI portion is missing, but you may be able to run the program directly.
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mgoodman
Bolt Sorter Illiterate Joined: Mar/14/2012 Location: United States Status: Offline Points: 1 |
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Can you please send a copy to michelle_in_rio@hotmail.com!
Thank you! |
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sandres913
Welding Master Joined: Aug/17/2011 Status: Offline Points: 216 |
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This guy probably just submitted all our email addresses to various "funny" sites...which would explain why my Gmail spam folder is constantly over 9000
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Ankit8500
Bolt Sorter Illiterate Joined: Apr/24/2012 Location: Asansol Status: Offline Points: 1 |
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can you please send me a copy at ankit8500@gmail.com
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Mod Squad
Welding Master Mutant Enforcer Joined: Oct/19/2010 Status: Offline Points: 200 |
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What can I say? Locked.
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stooge
Bolt Sorter Joined: Dec/13/2012 Status: Offline Points: 2 |
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SLASIM.zip
While looking for a suspension kinematic program, I ran across the following thread in this forum: http://forums.bajasae.net/forum/free-sla-suspension-kinematics-program_topic688.html I created the missing MATLAB GUI file and thought it might be of use to someone. |
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Mod Squad
Welding Master Mutant Enforcer Joined: Oct/19/2010 Status: Offline Points: 200 |
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So it seems as if this has come full circle. A GUI has been created and you can run the program. I'm going to unlock this thread for the time being.
Warning: If you join this forum and immediately ask where to get the software, as countless other have done before - You'll be banned and your post deleted. Edited by Mod Squad - Feb/13/2013 at 10:44am |
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vovesoinmori1
Double Secret Probation Joined: Oct/11/2017 Location: Mexico Status: Offline Points: 2 |
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it would be amazing if you could share the software: vovesoinmori1@hotmail.com
thank you!! |
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RLM
Baja Godfather Joined: Nov/15/2012 Location: Hamilton, ON Status: Offline Points: 1258 |
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Please read literally the 2 posts before you. the one directly before you says don't join the forum and immediately ask where to get the software or you will be banned... You did exactly what it said not to. the post literally before that has the link as the first thing typed.
in the future, before posting, read through THE ENTIRE THREAD and see if the information you are after is already there. If you are too lazy to read even the last 2 posts in a thread, maybe you should consider a different career path as there is zero tolerance for shortcuts in engineering.
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McMaster Baja Racing (09-Dec 2015)
Team Captain 2012-2015 Suspension Lead 2015-2016 All spoonfeed PM requests will be billed at $10 USD per reply, payable via paypal. |
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