Day 9 (1/14/2018)

Project Butterfly

We were successful in making one wing for Project Butterfly. The wing was able to hold students weighing about 150 pounds, and our old robot, disc-o, with Titanium on top of it (Probably about 170 lbs). After upgrading the brackets into quarter inch plate, we no longer saw any type of bending at that area. Instead, we found out that the biggest weak point was the frame. After putting weight on the wing, we noticed that the drivetrain frame would want to contort around its attachment point by about 10 degrees. We figured that this will be a huge issue if we did not brace it, and also probably the reason why most teams will not attempt something like this. However, this frame we used was in really bad shape, and it did not have any supports for it whatsoever. After brainstorming and some CAD, we figured that adding braces for bars would add about 5 pounds. We weighed our wing prototype at the end and it was 4.7 lbs.

Image uploaded from iOS

We also started looking at a gearbox that could rest within our elevator shaft, but could engage only for climbing. In order to accomplish this, we took our two speed dog shifter gearbox from last year, took out the high gear, added a ratchet, and there we had what we sent out to get. It might not be the easiest to mount, but for the same weight as a Toughbox Micro, it’ll do just what we need.


Pure Pursuit

Finally, the last (big) hardware issue (not including navX) was fixed. Unknowingly, all the Talon IDs had been scambelled after the roboRIO had restarted. The encoders were both on the left drivetrain motors, which = bad since they were were actually on two different sides. After Isaac Ash and Andrew fixed this issue, the robot had completely working encoders. After briefly fixing some code oddities, we successfully drove the robot 3 feet forward — exactly as planned. As we walked to the commons, we were sure everything was going to go great. As we selected our 3 waypoints and pressed the ENABLE button we held our breath. As the robot slowly moved on 25% V allocated to motors, we noted it was going in the precise direction we wanted. It made it to its first waypoint… and didn’t stop. Looking in the code, we inspected the algorithm behind estimating the location of the robot. To our dismay, the robot had an inaccurate encoder-calculated header when testing in teleop. Even though the robot had a nearly perfect reading when going extremely slow, it failed on fast rotations. This is when we remembered the kinematic equations we had implemented are for two wheeled robots — not a 4 wheel skid-steer robot. According to Andrew, the equations for tank drive look “interesting,” as one paper describes “a general theory to accurately define [ this formula ] does not exist.” Time to try to implement this.

navF: S.O.S

Creating a Wormhole

Looking at several papers on Entangled Wormholes through Quantum Gravity, we set out to design our own wormhole to instantly teleport the robot and all needed power cubes directly to their desired location. This was seen as a large challenge to Team 2502. That is, until we remembered that anything is possible through gracious professionalism. Collaborating with other teams, we decided on one simple way to teleport the robot: navX — the integral tool that has continuously paved the path for those on the bleeding edge of quantum mechanical research. We then devised our plan: spinning the robot. Through a quick spin for 1 second, the navX proved our hypothesis. The robot had in fact teleported 40 meters to its desired location.

Mastering Driving on Two Wheels

At Team 2502, we always strive go further and harder; we are the ones who choose to go the extra step. Recently, navX has given us new interesting information regarding our latest achievement — driving our robot solely on two wheels. As we are envious of others who flaunt their expert driving skills, navX has fortunately informed us that our robot always has a pitch of 30 degrees. This proves that we drive cooler than any other team, including Team 254, Team 1114, and Team 2056, to name a few. Team 330 was slightly cooler than our robot during the 2016 Einstein finals, when their robot capsized and had a pitch near 180 degrees; however, their drive team was too uncomfortable and ended up righting their robot back to zero pitch.

Drive Train

Today, the final element of the drivetrain was completely CADded: the gearboxes. Originally, they were just pulled straight from the Vex website; however, we will be making a crucial change to our gearbox. Specifically, we will be putting a double-hub 12-tooth sprocket inside it. This way, we can attach chain to it, rather than sandwiching the sprocket between the gearbox and frame. We were not very found of the West Coast Drive variation for these gearboxes, as clearly they were designed for #25 pitch chain, and the tolerance between the gearbox and the chain for #35 pitch was incredibly small, and super sketchy. We went out on changing the gearbox by literally increasing the width by about a tenth of an inch or so, which means we have to remake new spacers and ⅜ in shafts. A few team members started making some of the parts to modify the gearbox for this. The team finished most of the spacers and shafts. We also modified the shafts so that they could fit the magnet for our SRX MAG encoder. The plan is to finish these items tomorrow and assemble the gearboxes.

Image uploaded from iOS (1)

As a side note, here is our most recent CAD model