This is our fifth year of FTC competition. In past years, we have used Tetrix, Actobotics, and REV build systems. This year, we decided to switch to GoBilda. This was a somewhat more expensive strategy because we couldn’t use very many parts from the past four years.
The GoBilda system is metric, with most hole patterns based on an 8mm grid. The screws used to fasten parts together are M4-0.7, unlike the ANSI 6-32 thread we had used previously. The GoBilda system has several advantages:
- The standard U-channel is large enough that a drive motor can fit inside it. This allows our 4-motor Mecanum drive to consume no extra space in the robot.
- Many parts have tapped holes in convenient places, so nuts are often not needed.
- Their compatible set of parts is very large and complete.
- They provide STEP 3D CAD models for every part in their catalog.
Because we were able to get generous grant funding this year, we added a new 3D printer, a Prusa Research MK3S+, which opened the door to incorporating a great many 3D printed parts.
Because of contact restrictions due to the COVID pandemic, we were not able to share in the robot design work as widely as we would have liked. As a team, we brainstormed ideas and came up with a general idea of what mechanisms and methods we would use, but the robot detailed design and construction was done mostly by the team mentor. We have no team members who are able to use 3D CAD software except for our mentor. We do have a very able software designer, and he wrote all the robot code by himself.
Because of the above factors, we decided for the first time this year to completely design the robot in 3D CAD. We created the initial design and built the robot to that plan. Unfortunately, when the digital plan encountered reality and the software began to be incorporated, some changes were made directly in hardware with the digital model being updated after the fact. Other changes were done in the CAD model, especially when a 3D printed part needed modification.