Hello,
I would appreciate some help to get this simulation going, when I press start, nothing really happen, it goes too slow. Pics below if anyone can help. The slider/pin is supposed to move in the groove, riding on the gears.
Dynamic simulation, need help
Is this a school assignment?
This should be 3 bodies (not 1 disjointed body) or 2 (or 3) Components.
Use Rolling Cylinder on Cylinder for the gears.
Use 2D Contacts for the Pin rather than 3D Contacts.
Thank you for your reply!
No this is a small hobby project of mine. I'm trying to insert 2D contact joints but there's always a problem with them, trying to read about them but the information is sparse, the video on Autodesk's homepage is using obsolete Flash player.
In the pic, what am I missing? The normal orientation is wrong accordingly to a dialog box that says the system is impossible to solve, or the curves intersect at multiple locations.
Note that I have updated my design a bit and changed joints as you suggested.
Accepted solution
Based on your [@autoinv78's) mech-1.zip I got the attached result.
Unfortunately I don't have Inventor version 2019 (only 2020 an newer). If the shown result meets your goal I can try to describe in words what I did.
But for now I can tell you.: the transfer of the pin from gear1 to gear2 does not work stably. In some cases it works well as shown, in some cases it fails - the pin doesn't leave the gear1. Maybe some modifications on the design will be necessary.
Jürgen Palme
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In my attempt above (post #7) I could not create a 2D contact joint between the pin and the top plate. Do I decided to use a 3D contact joint and got the shown result.
But a 2D contact joint should be possible, I suspect a small incorrectness in your model (the upper plane of the pin and the upper plane of the top plate seem to be not exact parallel). Therefore I created the parts new from scratch.
Now (you can see it >>here<<) I get a result which works as expected. For me it look nice ;-).
For all who are perhaps interested I attach the 2020 files.
If you (@autoinv78) need more details feel free to ask.
Jürgen Palme
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Thanks! I could not open the newer 2020 files on my Inventor. I did some improvements on my design yesterday and added 3D joints between the pin and all components it can come in contact with. With cylinder on cylinder joints between the gears. I did manage to simulate it, the question is if the simulation is working as it should, like is it reasonable that for the pin to move maybe 30 degrees on one gear, the simulation time is about 30min? I have done simulations in the past but always managed to use the other, faster, type of joints.
My computer is a core i9-9900K with 32GB Ram and RTX2060S.
In attached pic, I made some changes to the pin, making bottom part oval and added a round sweep around the upper part, my idea is that it should reduce contact surface between parts and thus speed up the simulation, but I don't know if this is case; guidance appreciated.
... and added 3D joints between the pin and all components it can come in contact with
3D joints need generally much more computing resources than 2D contact.
... to move maybe 30 degrees on one gear, the simulation time is about 30min
That seems so be too much. But without knowing your files (.ipt, .iam) I only can guess. A first idea: A simulation needs much time if you have overlapping parts (collisions) in the assembly already before starting the simulation. To check (and avoid) this do a collision analysis before starting the simulation. (My video in post #8 shows the creating a simulation in real time - in less than 40 sec the pin moved several times around. And my laptop has much less power than yours)
... added a round sweep around the upper part
I doubt that this measure will reduce the computing time, probably even the opposite will be the case. I think Jeffrey ( @JDMather ) can answer this question more competently.
Jürgen Palme
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The main problem are (again) the 3D contact joints, as you can see in >>this video<<. Whenever possible you should avoid using this joints.
Even if I would define some joints other than you did (e.g. I would give all three gears a Revolution joint, but this has nothing to do with your current problem), in the video I show how you can use 2D contact joints instead of the 3D contacts.
As in your previous assembly again here a 2D contact between the pin and the top plate is not possible. But theoretical it must be possible. For now I do not want to analyze why this happens. Above I have shown that (after a new creating all the parts) also between the pin and the top plate a 2D contact IS possible.
(If I find the time I will try to solve this last problem too. Maybe you yourself will find it sooner)
Jürgen Palme
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@j.palmeL29YX wrote:
(If I find the time I will try to solve this last problem too. Maybe you yourself will find it sooner)
Something seems to be unprecise in your assembly. After deleting all your Relationships and creating new (and as you can see others) and also creating new joints in the DS (no one 3D contact is necessarily) the simulation >>runs perfect<<.
HTH
If my reply solves your problem, click the "accept as solution" button. This can help others find solutions faster
Jürgen Palme
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@autoinv78 wrote:
Wouldn't 3D joints give the most realistic simulation?
...
Shouldn't 3D joints always work?
You're right, they SHOULD. But unfortunately, sometimes they DON'T. Yes, there is some "black magic" involved and the software has its problems and limitations.
>>example<< without any comment 😉
But we must not forget: in a lot of cases it works well and lets us achieve the expected results.
The better we understand the functionality of this tool, the more we're exploring its capabilities and limitations, the better we can use this tool with success. What you're doing ("play" with this tool as a hobbyist) is a good way to get more experience. And gain the better results you will get.
And yes, dealing with this tool (DS) can also be a lot of fun.
Don't worry, be happy 😉
Jürgen Palme
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