I’ll share my team’s strategy and some of the technical problems. I would greatly appreciate any suggestions you may have. We don’t have the most experience, so an MCC-style robot is the best option for us.
We decided to build an AMP-only robot that can climb the chain with a teammate. We think this is the best strategy for us because we can make a major contribution towards the MELODY and ENSEMBLE RP during Qualification matches. In Playoffs, we will Amplify our alliance partners’ Speaker shots 3-4 times.
The intake has 3 rollers and can rotate to score in the AMP or pick up off the ground. Very similar to Penn State Ri3D. For Climbing, we will be using 2 AM Climber in a box kits, one on either side.
How should I mount the climbers and the rotating arm without them interfering?
How should I mount the motors powering the 3 rollers?
Looks like a cool design. Depending on how wide/long your robot is you can either mount the climbers on top of the drivetrain meaning you could be thinner which may help for climbing next to someone or you could mount them on the sides of the intake but inside the chassis. In terms of running the intake, you could probably run it off of one motor if you wanted to by belting the two rollers that go together, together and then by putting a gear on the back roller connected to another gear which is belted to the front independent roller. In terms of rotating your intake I would suggest a gearbox to use multiple motors to rotate it or to get planetary gearboxes to increase the torque of the motor/s to help it move more smoothly.
I would suggest this for your belt path and motor location because of the rigid arm. Ideally keep the motor in the frame perimeter when the arm is down, or at least in the bumper perimeter.
Use a figure 8 belt (timing or polycord) to reverse the direction on the intake rollers.
Maybe make a guard plate of thin polycarbonate to protect the pulleys.
Next thing would be the mounting plates and a cross shaft for (probably 2?) motors to lift up the arm.
You will likely want to make the pivot shaft a live axle so you can connect a encoder to it so that programming knows precisely the angle of the arm without having to go through a bunch of gearboxes. You will likely want to use some planetary gearboxes and a final chain reduction, think maybe a 18-24T sprocket on the gearboxes and a ~60tsproket on each of the arm sides.
You will also probably want to place a pair of gas springs on arm to help counter balance it.
Red is cross shaft, mounted to the uprights with something like an Andymark hex hub with 1.875inch bolt pattern.
You would have plates attached to the frame with half inch hex bearing for the pivot point and mounts for the motor and small sprockets (orange). You may also put a rev through bore encoder on here as well (purple).
Large sprockets (green) would be attached to the hex hub (which is also bolted to the arm, it all spins together)
Some gas springs (yellow ) could be attached to the arm to help push it up when it is low to the ground and gravity is acting on a long lever arm.
3739 used this last season and it worked out great. We 3d printed the hex nub pictured above, and glued it into the bore of the dead axle. The encoder body was bolted to the wrist itself, so the hex bore stayed still with the dead axle and the body rotated with the wrist. If you want to get fancy you could machine the nub out of aluminum or delrin but we never had any issues with just running PLA
