Strike Zone, Team 5460 is proud to post its 2019 Robot CAD, Voyager. Software used was SolidWorks, and three students and one mentor was involved in the process. This is our most complete and well organized model in our team history. We had most of the CAD done by the end of the second week in build season. If you have any questions, feel free to ask. Enjoy!
How do you organize multiple people working together on the same CAD project? Our team has one person per subsystem more or less and then we have one person integrate all the models, do you have something similar?
Yes, we do something similar. For the most part, each person works on a subsystem. We use GrabCAD Workbench to share files between different people. Each sub-system gets a folder (chassis, elevator, carriage/arm, ball intake, and climber) which is all located in the project folder. Outside of the project folder in our GrabCAD folder, we have a common parts folder where we keep everything from Vexpro components, to bolts and nuts, etc. Communication is key between different people working on different subsystems so you don’t over write someone’s changes. As far as the main assembly, we take turns editing it. When someone wants to view the main assembly, but doesn’t want to edit it, you can reload it as read-only so you don’t overwrite someone’s changes.
So do you have one person integrating each subassembly into the main one? Also how does that communication work, like do you use large robot layout sketches to figure out the interface between systems?
For the most part, one person is in charge for the integration of sub assemblies. As far as communication, we have CAD meetings to help with this (We will be improving this next year by using Slack more often). We use layout sketches for sub systems, but not for interface with other sub systems. Most things on a FRC robot depend on the chassis, so make sure to have the chassis done as quick as possible so it can be used as reference for other sub systems. This year, after we decided on our elevator offset, we used planes in the arm sub-assembly to design the arm. Next year, I would like to use sketches to link the different sub-systems.
would you be able to share a STEP file? i’m having issues with the SolidWorks files.
I have uploaded a step file in the gradcad.
Why did you decide to use a CIM to drive your cargo intake roller?
We used a 775 pro motor for our external intake rollers. You might be looking at our drivetrain gearboxes which have 3 minicims each side.
Excuse the crude drawing, but isn’t this the drive system for your intake roller?
The motor that drives the arm cargo wheels that you have shown there is a Bag Motor (217-3351). We chose to use a bag motor due to the low stall current when compared to a 775, as the wheels hold the cargo ball in.
That’s a BAG motor. They look similar to CIM motors, but are much smaller, have higher RPM, and lower torque. It’s a great motor for intakes.
Wow, I haven’t seen a bag motor on a robot in a long time. It hadn’t even crossed my mind. Sorry about that lol
From my experience these are still pretty common. My team still uses them as well as a lot of other teams that I know.
How did you manufacture the bearing blocks used on the elevator carriage? I love how compact they are. Did you 3d print them or were they done on a mill?
We use bag motors for just about any rotation outside of the drivetrain. Intake rollers especially. We even used a bag motor to power our arm this year, thanks to the help of some surgical tubing.
Yes the bearing blocks on the carriage are 3D printed out of PLA. They are inspired by 1678’s bearing blocks from 2018.
Why did you switch to using McMaster Carr oilite bearings on the arm instead of the regular Vexpro ones? Also, why use them on the intake?
Did you have any issues with having plain PLA bearing blocks? Most 3d printed parts I have seen in higher load scenarios have all been fiber reinforced or nylon.