Pegasus was designed and built to play the 2024 FRC game Crescendo and will compete at the Berrien Springs District Event (March 2-3) and Troy 1 District Event (March 23-24)! We hope to see you there!
General Robot Specs:
Max dimensions: 29"x29"x47 3/4"
Overall weight: 123 lbs
Drivetrain:
Four wheel swerve drive utilizing MAXSwerve modules
Capable of a max speed of 16fps
Shoulder and Arm:
Powered by two NEO motors that drive the arm at 120 degrees per second
Arm supported by large diameter MAXSpline shaft
Gearbox mounts are slotted and chain tension is maintained via a cam system
End Effector:
Integrated double roller intake, feed roller, and double flywheel assembly
Capable of acquiring game pieces from the floor and human player load station
Scores in speaker (high goal), amp (low goal), and trap (climbing goal)
Each set of flywheels is powered by a NEO motor, the intake rollers are powered by a NEO 550 motor and the feed roller is powered by a NEO 550 motor
Comprised of elevator masts and powertrain, hook assembly, buddy bar, reaction bar, and lock mechanism
Powertrain is powered by a pair of mechanically connected NEO 550 motors, each with a 30:1 reduction - capable of climbing at 19 in/s and has a stall load of 640lbs
Buddy bar provides a friendly climbing surface at chain height for alliance partners to earn extra points
Reaction bar stabilizes robot against stage core
Robot maintains elevation by a pneumatically actuated ratchet and pawl lock to prevent backdriving
Limelight cameras track field mounted AprilTags for scoring alignment and floor pickup of game pieces
Robot utilizes a gyro and a suite of encoders to execute pre-planned paths during autonomous and odometry and pose throughout a match
Arm and flywheels are controlled by full PID loops
Drivers’ station contains a suite of prognostics and diagnostics to identify and address sensor failure, voltage regulation, and the like.
Lastly, we want to give a shoutout to FRC 3005 - The Robochargers for inspiring a significant amount of this robot’s design, from the swerve modules themselves to the bumper mounts!
Pegasus and our 2024 season would not be possible without the generosity and guidance of our sponsors! We thank them for the opportunities they are able to give us!
Not intending to turn this into an Open Alliance style thread, but I figure I might as well share some lessons learned and next steps following Berrien Springs. Considering the hurdles we faced, #6 alliance captain and a Creativity Award is a good outcome - not bad for a team with ~14 students that regularly show up, but we’re striving for better outcomes at Troy 1!
Lexan and cleaning solvents don’t mix. Our initial end effector side plates were cut out of reclaimed table dividers from COVID. Who knows how many times they were wiped down with disinfectant, but it only took one hard hit to propagate a series of cracks through both plates made out of the now brittle material, and after three matches, it was time to switch to the spare. Unfortunately the spare also cracked after the gyro reset and caused another hard impact. Luckily, the spare stayed together after some splints were added, but there was still enough play local to where the feed roller motor mounted, which caused belt slip and difficulty expelling notes.
7075 for hex shaft, almost always. Our shoulder gearbox output shafts were cut out of 6061 aluminum and developed significant bending halfway through the event. After swapping out for 7075 and tying together with a coupler, the shoulder seemed to run smoother throughout the rest of the event.
Climbing hooks need ample clearance. When we designed the climber, we knew that we were on the razor’s edge in terms of clearance and climber travel, and it resulted in our driver having more difficulty than expected trying to get the hooks over the chain. And because we did have so much difficulty climbing, we took off the buddy bar such that it wouldn’t get in the way elsewhere (we think it will make a return for Troy). When we did climb, it climbed nicely, and we’re already working to ensure we climb more frequently at Troy.
Trap is tough. Very few traps were scored at Berrien Springs so we don’t feel like we missed out, but that will possibly change as the season progresses. Pegasus can climb high enough - we just need a means of curving the note into the trap itself.
Properly timed amplifications are key to winning matches. It’s one thing to understand this strategic insight, it’s entirely another to properly time your amplifications, which is not an easy feat.
Floor loading at the source is also tough. The time spent gingerly approaching a note and trying to figure out from 50 feet away if the robot actually grabbed the game piece is hurting our cycle time. If we can’t figure out an efficient way to tackle this, HP loading may be the way for us to go.
It’s nice to roll up to the first event and be able to say that your team has a 4 note auto, but that center starting point is a popular one. We’ll need to diversify our autonomous offerings if we want to contribute.
End effector iteration. Through some recent testing, the team is adjusting the lexan floor to be better supported and better align with the flywheels, resulting in both improved intake and a more accurate shot. The feed roller was also removed and the flywheel motors were repackaged to the arm. The resultant open volume will soon be used for a more robust camera mount and a trap assist device.
Climber hooks were recut with new bearing block spacing and a slightly higher hook, which should allow more forgiveness for our driver during the endgame. The reaction bar was also adjusted to account for this change in height and also lengthened and hooked to ensure that they catch the bottom of the core.
More auto paths and fine tuning of everything else. We’re striving to have our mechanical adjustments wrapped up by Saturday such that programming can have a week to work their magic.
It’s a significant amount of work to get through in the two and a half weeks between events, but it doesn’t feel insurmountable…yet. Pegasus should be rockin’ and rollin’ for Troy!
