Team 94999E - Yokai Mid-Season Reveal
We are proud to present our mid-season robot for Change Up! This bot has been used at two tournaments so far, throwing one and winning the other. We have leared a lot when building and competing with this robot, as we hope to convey below.
About the Bot
The most notable subsystem on our robot is our intakes. When designing, we wanted something space efficient when folded up, as well as something that would provide even compression on the ball. In the end, we decided to attach the intake using a 4-bar linkage.
As the 4-bar allows for outward movement of the intake at any point, we have even compression on the ball, allowing us to more easily tune the intakes. In addition, we were able to use the movement of the 4-bar linkage for a compact deploy, as shown.
(Old picture from when we still had an ejector)
The main downside of these intakes is increased slop in the joints. Due to the compact nature of the 4-bar, we were unable to use proper screw joints for the 4-bar joints. Because there is nothing bracing the screws in one place, they have a tendency to loosen and become sloppy. While this does not impact the performance of the intakes, it is something we hope to fix in future iterations.
Most other parts of the robot are pretty standard. The backboard is not the cleanest, so we plan on replacing it in the near future. We added a wedge onto the back in hopes of performing better defense, and it does work, my driving just doesn’t utilize it to the fullest extent. We will be removing the wedge as Live Remote Tournaments become more prevalent.
As for why we removed the ejector on the back, we simply did not use it. We figured we would be better off attaching the motor to the indexer, allowing us to run the high speeds we show in the reveal. The rubber band ramp for the balls will likely be replaced by a more efficient surface, plastic, later in the season.
One issue we noticed in the design this afternoon is the indexer jamming. If the robot gets too close to the goal, the ball will sometimes not go into the indexer, but rather jam it against it and the plastic of the goal. It’s fairly hard to explain, but it is visible in our match videos. We believe this can be fixed by increasing the distance the hard stop is from the robot, so it should not take long to fix.
We have competed at a tournament today (2/27 as of posting), and here is some match footage from the event.
Qual 18: VEX Change Up 94999E - Unofficial Whitewater Tournament Qual 18 - YouTube
Quarterfinals: VEX Change Up 94999E - Unofficial Whitewater Tournament Quarterfinals - YouTube
Grand Finals: VEX Change Up 94999E - Unofficial Whitewater Tournament Grand Finals - YouTube
These were just updated as I’m typing this, so the resolution may not be up to 1080p just yet. I will remove this part when it is.
Thank you for watching our reveal, and good luck in the rest of the season! If you have any questions, feel free to ask.