Nice Video, i saw you added a few thing since supers. Good luck at worlds! Btw our team got invited a few days ago, but we decided not go since we had no preparation time. I look forward to seeing your team again next season. -Frogbots
how did you fit dual intake... and a cap ball lifter... Impressive!!! Also props on the mechanum code, ive seen too many ftc teams use mechanum wheels but a tank drive system, totally wastes the potential
We used a dual intake because the balls were scattered all over the field after scoring. We found it was super useful to not have to turn around for collecting a nearby ball. It was definitely a challenge in terms of space but it was achievable.
i had been working in using the mecanum wheels, but i don't really know how to attach them to the motors, they don't translate to the right of left with too much accuracy the any tips...
Honestly, we didn't do a lot to tune this, but here are some suggestions: 1. Make sure the wheels are arranged in an X pattern when looking from the top (see ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ekWbyrjyMUY.htmlm26s) or an 0 pattern from the bottom 2. For competition, we used the Nexus wheels (www.robotshop.com/en/100mm-mecanum-wheel-set.html) which have bearings on the rollers to reduce friction. We found that the vex wheels were hard to mount in a reliable fashion and introduced lots of variability 3. We mounted the wheels far apart at the four corners to maximize the size of the square, this makes it so that the small adjustments in the wheel movement by a single wheel have a smaller affect on the robot's heading 4. We tried to distribute weight properly so none of the wheels would bear more weight than others, although we didn't do any measurement of this 5. To make our robot drive faster we geared up the AndyMark Neverest 40 motors 2:1. If you are doing chain drive make sure the chains are all a good tension or that could lead to some drifting and inaccuracy 6. We also used the Adafruit BNO055 gyro sensor to ensure the robot is always facing the correct heading with a PID loop No matter what, we are still using relatively cheap robot parts so don't expect to have a perfectly straight translating wheelbase so you have to account for it in your programming elsewhere
The balls just sit inside the cavity of the robot. When we want to feed the balls up to the shooter, we rotate the white internal roller the opposite way. You can see the change in direction of the white roller at 0:38 in the video.
The rotating cylinder is just PVC wrapped with Brainstormers-color duct tape. For the tubing, McMaster 51075K is tygon rubber. 5108K is polyurethane. 5173K44 is nylon.
McMaster is great for tubing. We used 51075K24 for the collection tubing. For internal movement of particles, we also included 5108K46 and 5173K44. It's not expensive to get 10 feet of each to try. Main attributes we cared about were friction and stiffness. The tubing material affects friction and its durometer rating affects stiffness.
