BigWheel+

Tags: think, design, and innovate
Personhours: 4
BigWheel+ By Evan

Task: Continue work on BigWheel

Since the last time we have discussed Bigwheel, the robot has gone through a few major changes. First and foremost, it now has a flipper arm. Since the robot itself is the lift mechanism, we had to put a lot of work into the design of the flipper. Right now it is a 10 inch REV rail attached to two of the largest REV gears you can buy, with a custom 3D printed mount housing an omni wheel pair. Right now it’s turned by two pairs of the smallest REV gears you can buy creating a 3:25 gear ratio. It’s a bit odd, but it increases torque which is what we’re going for, the philosophy being that it’s better to be smooth than to be quick, as a quick robot is weaker and less controllable. On top of the flipper, we’ve added extra supports on the arm mounts, as when we went to the Hendricks scrimmage, we found that the two sides were out of alignment, and one was bending more forward than the other, making the arm bend unevenly to one side and throwing the whole robot out of alignment. The next step is to strengthen the arm itself, as the two sides have a tendency to want to do their own things, mainly the side with the intake motor mounted to it. Since the supports have been put in though, Bigwheel has been functioning much better, and the arm no longer flops to one side. General wire management has also taken place, as previously the wires went every which way and created an infuriating mess that had the potential to get caught in the gears. Personally I’ve noticed that we’re a tad out of touch with gears right now, none of our other robots have sported them to much degree. We’ve been really in touch with sprockets though, since they’ve featured heavily in our designs the past two years. That’s just an observation, and since my first awareness of this, I’ve seen our gear savvy grow.

Next Steps

Bigwheel was built on a bit of a shabby base, mostly being made of a piece of polycarb and some aluminum bars, and not giving much in terms of change. We’ve cut here and there, drilled a few holes, unattached and re-attached a couple of things, but in all it’s a very stiff robot, and doesn’t lend itself to fluidity of design. That’s why we plan on making a second version of this base, hopefully with thinner polycarb and more secure sides that have been welded together but can be removed more easily. The exact design is still being modeled, but we have a direction to jump off from, and I believe we can make that leap to a better robot.

Date | October 13, 2018