pic: Chassis Idea

[Rion Atkinson]

Originally Posted by AdamHeard

Okay, that is definitely not 43 lbs.

What you need to do is make sure every component is set correctly. If it's a machined part or metal piece that is a uniform material set it's material in SW, that will make apply the proper density and weight. For everything else go to tools > mass properties > check the box for assigned mass properties, and manually assign a mass. CIMs are 2.75 lbs, compressor ~5, etc... Someone posted a spreadsheet a while back that had most of the electronic's weights. You can do assigned mass properties for an assembly, and ignore the properties of it's components; for example, set the shifters to 3.4 lbs + 2.75 lbs (the weight of a CIM plus the gearbox).

As for trusting parts that have been imported or given to you from others; just don't. If a goal of yours is to use your CAD model to provide accurate weight estimates, get in the habit of making sure all parts are set correctly as they are made and/or inserted into the assembly. It is a horrible experience trying to figure out later on why the robot is 20 lbs lighter/heavier than you think it should be and you have 1000+ parts in the assembly.

Thank you for this! I probably would have been killing myself come build season while working on CAD... Thank you very much. I'm going to get started on changing all the masses.

Originally Posted by ,4lex S.

A Box Drivetrain like this generally looks quite good on its own, but when you consider a real FIRST robot, some flaws pop up. From a structural standpoint, you need to ensure that you will be able to adapt this design to manipulators.

About 50% of the time my team had to take a chunk out of the front of the chassis to facilitate claws or collectors. Just keep this possibility in mind and adapt your design for potential geometry changes.

If you can't get it welded, this design should work quite well with rivets. Triangular corner gussets might be a good idea for some of the pieces, rather than just right angle aluminium.

This is really just my first step in designing a working FRC chassis. I would except part to get chopped up. If they didn't, then the GDC decided not to be evil... (Wouldn't that be the day. )

I have seen pictures of riveted Aluminum chassis so I figured I would be pretty safe in doing so. When I get far enough into the design process I will probably create a CAD with those in it. (Yes rivets and all. I may add wires... )

-Rion