transmission simulation

[Apache64]

I need recommendations for a way to simulate an operating transmission preferably with actual, dimensionally correct (scaled) gears shown, instead of stick figures. Being new to the simulation thing, I'm just looking for a starting point, thanks.

 

[GregLocock]

If you are very serious about it then ADAMS will allow you to model the mechanical behaviour, and can superimpose 3d models of the gears onto the underlying model.

If you just want an animated picture of the gearbox as it shifts gears and so on then you are probably better off with a 3d animation package. As a halfway house something like Solidworks may be wrth investigating.

It all dpeends on what you are trying to do in your 'simulation'.



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[MikeyP]

Before I start I will declare an interest: I am commercially involved with the following software, but I am not trying to sell it to you!

RomaxDesigner is a transmission design and analysis package. It will easily cope with the 3D animations of the transmission in operation. It also goes much further than that, doing full static analysis for gear, bearing and shaft durability as well as dynamic analysis for NVH. It is also extremely expensive, so if this is a one-off for you then forget about it.

If you are interested, have a look at

http://www.romaxtech.com

M


--
Dr Michael F Platten

 

[geesamand]

What kind of simulation are you looking for? Visual or performance? The two are sort of exclusive, since the visualization of turning gears is of little consequence during the technical design phase.

Dave

 

[Apache64]

This would be a current production gearbox, no design, so I guess it should be characterized as demonstration software. What I'd like to come up with is SOME kind of visual model that I could pull up whenever I field questions about its operation (frequently). It would be beneficial if it could be shown at normal operating speeds where I could drag over a specific component and a get specific gear data (material, type, teeth, speed, etc.). I may have to back off of the 'scaled' model due to cost after looking at some of the options above and just go with a stick model. I appreciate the feedback.

 

[crysta1c1ear]

I have raytraced gearbox pictures with a free copy of POVRAY, used the 'clock' variable to create pictures at one frame time intervals, combined the images into a video, MPEG encoded it and put it onto CD in Chinese Super Video CD format to play on a DVD player.

It is easy to make web pages with still images and hot-spots, so one could click on parts to see pre-produced videos of their operation or details of them.

You don't want to show gearboxes running at real speeds, as you would just see a blur, or pieces spinning the wrong way. Make sure no tooth moves more than half way to the position of the next tooth between frames. If a tooth A moves 90% of the way forwards to the position of the next tooth B, the mind will see tooth B moving 10% of the way backwards towards tooth A. It is a beginners mistake for video, but being transmission specialist rather than video specialists, I have seen it done on a Torotrak video and on the Getrag screensaver.

I didn't mention Raytracing before, as you'd have to program the maths of the mechanical behaviour, learning raytracing, program in the anatomy of the transmission - which I wondered if you had in some CAD program somewhere, etc.

With scalar vector graphics (SVG) you could draw animated 2D stuff, which could then be viewed in a web browser and zoomed, with clicks to restart animation, etc. SVG will run on mobile phones soon too.

There are several reasons for me NOT to post this.
One is that it would take forever and a day to come up with something worthwhile. Another is that the you cannot rotate or zoom the animations in real time.

I have a dot EXE file from a Paris motorshow where a transmission designer had a 3D animation of their 6-speed automatic. The program runs on any PC and you can rotate the transmission in real time, or click on numbers to see how the different ratios work. It was schematic. But I assumed that you wanted that sort of playstation manoverability.

Last week I created an web page with two FRAMES, a FORM in one frame where I can enter sizes of certain gears, and another frame to display a SVG which shows the relative sizes of gears (ie to scale) and graphs the ratios that the transmission produces.

There seems to be lots that one can do, all with its own advantages and disadvantages: portability, bandwidth, interactivity, etc. However, if you are doing everything yourself with cheap tools, then time will probably be the big constraint.