Hi all, quick question. For a school project, part of what I am doing is having a vehicle run on a track. However, when I add the vehicle assembly to the track assembly, the wheels and gears will not turn; however, they do turn in the vehicle assembly. I have ensured that the sub-assembly is set to flexible, but this still does not fix the problem. Is there something else I can try? Youtube, Google, and my textbook have not been much help. Just to clarify, I'm not asking for someone to do my project for me; rather, I just need some help solving an issue I am having with the software. Thank you.

 

Edit: Some more information, if it is helpful. In the vehicle sub-assembly, when the chassis is fixed, the axles, wheels, and gears all move. However, when the chassis floats, nothing moves.

 

Message was edited by: Thomas S


Categories: Modeling and Assemblies, Assemblies

Comments
Last comment By: Thomas S   Thu, 06 Dec 2018 22:58:46 GMT
Re: Flexible Sub-Assemblies Not Moving

How many levels of sub-assembly structure do you have?

By: Nadia Shea  Thu, 06 Dec 2018 21:21:33 GMT
Re: Flexible Sub-Assemblies Not Moving

Just the one level (main assembly and one sub-assembly level).

By: Thomas S  Thu, 06 Dec 2018 21:24:42 GMT
Re: Flexible Sub-Assemblies Not Moving

Can you share a copy of the file?

By: Nadia Shea  Thu, 06 Dec 2018 21:45:49 GMT
Re: Flexible Sub-Assemblies Not Moving

Hey Thomas,

 

I'm not sure how you could make a tire roll on the ground from just using a flexible assembly. You could have it ''translate'' on the ground, but having the rotation implies that SolidWorks would have to calculate the circumference of the tire to know how long it takes for a full rotation of the tire to happen.

 

Perhaps it is doable tough.

By: Alex Lachance  Thu, 06 Dec 2018 21:48:59 GMT
Re: Flexible Sub-Assemblies Not Moving
By: Nadia Shea  Thu, 06 Dec 2018 21:57:32 GMT
Re: Flexible Sub-Assemblies Not Moving

I attached the vehicle assembly, and the assembly containing the track and vehicle. I apologize for the simplicity of the design; I'm a freshman and new to this.

 

Thank you!

By: Thomas S  Thu, 06 Dec 2018 22:01:31 GMT
Re: Flexible Sub-Assemblies Not Moving

We are supposed to use a motion analysis and contact mates to make it roll.

By: Thomas S  Thu, 06 Dec 2018 21:54:38 GMT
Re: Flexible Sub-Assemblies Not Moving

Thomas S wrote:

 

Hi all, quick question. For a school project, part of what I am doing is having a vehicle run on a track. However, when I add the vehicle assembly to the track assembly, the wheels and gears will not turn; however, they do turn in the vehicle assembly. I have ensured that the sub-assembly is set to flexible, but this still does not fix the problem. Is there something else I can try? Youtube, Google, and my textbook have not been much help. Just to clarify, I'm not asking for someone to do my project for me; rather, I just need some help solving an issue I am having with the software. Thank you.

If the wheels turn in the vehicle subassy, but not in the top-level assy with the car on the track then there is a constraint happening at the top-level.  You should have only a couple of constraints attaching the vehicle to the track, such as a couple of tangent mates with the wheels to the track surface.  Try suppressing all mates of the vehicle to the track except for the most basic ones and see if that frees up the wheels to move.

 

Keep in mind that freedom to move does not mean they will move as the vehicle is moved along the track.  For that you would need a rack and pinion mate between a wheel and the track.

By: Dennis Dohogne  Thu, 06 Dec 2018 22:04:23 GMT
Re: Flexible Sub-Assemblies Not Moving

There are no parts so the assemblies open up empty. Use Pack and Go to get the entire top level.

 

2019 SOLIDWORKS Help - Pack and Go Overview

By: Nadia Shea  Thu, 06 Dec 2018 22:10:14 GMT
Re: Flexible Sub-Assemblies Not Moving

I can't believe I did that. Thank you.

By: Thomas S  Thu, 06 Dec 2018 22:18:43 GMT
Re: Flexible Sub-Assemblies Not Moving

The wheels and gears do not move when the vehicle is added to an assembly, even when not constrained to a track. They move fine if the vehicle is not a sub-assembly (e.g., when the vehicle file is open). I apologize if I didn't communicate clearly.

By: Thomas S  Thu, 06 Dec 2018 22:09:35 GMT
Re: Flexible Sub-Assemblies Not Moving

The issue you are seeing I think though is too MANY degrees of freedom. If the vehicle isn't somehow constrained a bit, as you tug on the wheels, it's easier to just move the whole vehicle than it is spin the wheels with all those gears. I constrained it with a parallel mate to the track and a width mate to the track and the wheels started spinning just fine.

By: Nadia Shea  Thu, 06 Dec 2018 22:35:11 GMT
Re: Flexible Sub-Assemblies Not Moving

I applied a parallel mate and a width mate to the chassis and the track, but the wheels and gears did not turn, and the vehicle could move up and down. Moving up and down is good, as I need it for my motion analysis. However, I'm not sure if I applied the parallel mate and width mate incorrectly somehow. Thank you for your help.

By: Thomas S  Thu, 06 Dec 2018 22:58:46 GMT
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