Team 2344 from Clear Springs High School in League City, Texas presents our first prototype for VEX Toss Up. A more refined version of this robot will be competing in Houston League Play and the Houston regional.
Goal Strategy: Fast (six, 393, high speed internal motor drivetrain), light (even though all steel), and agile offensive robot that can cross the bump easily, go under the barrier, score both small balls and large balls in/on the stashes and zones, and possibly hang (most likely low hang with a large ball). Primary focus in game is to fill up the stashes first and then engage in a back and forth fight for the big balls.
Current Robot Capabilities: Slow (six, 393, low speed internal motor drivetrain), light and agile robot that can score only small balls in the stashes and zones but can cross the bump and go under the barrier. We have a plan for big balls but have not yet implemented it. We have decided to wait on hanging until we have acquired a field.
Drivetrain: Six wheel base with omniwheels on the corners and high traction tread on large high strength sprockets in the centers. This allows us to turn quickly while still not being pushable from the side. Our wheels stick out from the base to allow us to go over the bump. Chain (removed in picture) running through all of the wheels insures that even when we are on only some of our wheels, we still have the power from every motor.
Lift: Chain bar powered by two 393 high torque motors geared at 5:1. We chose a chain bar to cut down on the weight that would have been required for something like a 6-bar. 11.5 inch tower allows robot to go under barrier and extends to 25 inches to score into stash.
Intake: Two medium sprockets with long flaps on every other link powered by one 393 torque motor each (may be switched to speed after testing). Rollers passively flip down from stow after start of match. Holds full three small ball capacity. Made to be as light as possible for speed in the lift and to leave room for development of a big ball manipulator.
Hanger: Nothing at the moment but we have some ideas…
This is the first year that we have done any work before summer so any feedback would be greatly appreciated. We would like to wish all teams good luck in their endeavours to be the apex.
Nice to see some fellow Texas teams getting prepped for Toss Up. If last year was any indication, this is gonna be a heck of a season. Hope to see you guys at the Houston league again. Good luck with your prototyping; you are off to a good start.
i really like how light your intake looks. Maybe i can use a 1 x 25 bar in the center like you guys. The slightly larger center wheel for traction and ease of turning is a good decision. Motoring each wheel then linking the powers was also a good call.
However, Your chain bar looks a lot longer than it needs to be. Maybe you can move your tower forward a bit more so you can add counterweight or maybe you can swap the 17.5 channels with 12.5 channels. You’ll get more torque, and thus you can attach more systems. Also, your arm doesn’t look fastened well. While raising, i think your tower will shake back and forth slightly. Also, though it’s an easy fix, your electronics look a bit messy. You probably want to provide a guide for your intake’s wires so it doesn’t get caught in your gear tower. I would also worry a bit about your center of gravity.
I’m curious about the chaining of your drive though. It looks like it’ll hit the bump. Not sure if i like that or not. Sure it puts stress on the chain, but it should be strong enough to handle that strain. On the other hand, it can operate like tank tread, pushing you over the bump. however, that means that your wheel in contact with the ground and the chain pushing on the bump would spin at different speeds. So it’s not really a benefit, just a way to reduce negative aspects. So as for that part, idk what to think yet.
Thank you for your constructive criticism. Unfortunately we cannot move the arm forwards more than maybe a quarter of an inch. As for adding a counterweight on the back, that will most likely be a later addition once we get some elastic. I’m glad that you noticed the “unique” wiring job. The day after these pictures were taken that was fixed. Your concerns about the center of gravity are well founded. The largest issue with this prototype is its center of gravity. With the arm at the top it tips backwards very easily. We are having trouble with this problem as we do not want to add weight and building something like a kickstand off of the back is proving difficult given that we have to be able to tilt to get over the bump. Yes our chain will hit the bump depending on how we route it. We have only tested going over the bump with shoes and random objects around the room. Once we get a higher fidelity bump we can decide whether or not we want to be riding on our chain.
Thank you! We spent quite a few hours looking at your chainbar tutorials for inspiration and we love what we have. As for the large balls we are planning on a simple forkliftesque mechanism with two sticks coming our of our intake that slide under the ball. Hanging is more of a secret although we have had some inspiration in this endeavour. Videos are a maybe considering that we have very limited access to our robot during the summer and currently have no game pieces (we have done some intake testing with a barrel from Gateway and a tube from Round Up).
The arm does not need to be at the full height to be able to score in the stashes. We’ve done some more work now that the school year has started and have found that we can score the buckys with the lift as much as 4 inches forward of its maximum height. This, combined with some programming that is coming soon, should fix the tipping problem. If all goes well, we might be able to get some video of the updated robot tomorrow.
As promised. Sorry it’s a bit late. Some major changes to the intake were made between the pictures and this video. Tipping is less of an issue now that we have a potetiometer and preset hieghts for the arm. The big ball manipulator is still a work in progress but you can see the start of some mounts on top of the rollers. Once those are working I can post some close ups because it is a really interesting mount.