The Robot
[LIST]
*]Chassis
The chassis is powered by 4 high speed 393 motors. The motors are geared together to power the main drive sprocket. The sprocket ratio for the drive train is 1:1. The chassis was designed to have a channel that goes all the way through the chassis, allowing game pieces to pass and making autonomous much easier.
*]Arm
We used a 6-bar linkage to get a max height of 35 in. The arms are powered by 4, 269 motors, geared 1:7 for torque. The arms themselves are made of aluminum metal, which put less stress on the motors.
*]Manipulator
The manipulator is like a cage made completely out of aluminum with intake rollers on the bottom on all 4 sides. All 4 sides are connected using bevel gears, and powered by 2, 269 motors. It can pick up both barrels and balls, and it can pick up the barrel in any orientation. It can hold up to 5 games pieces, but in normal game play, it can hold up to 4
Very nice. How fast does it pick up and score? How fast does it drive? And doesn’t the fact that the omni-wheel and the regular wheel are driving the same speed cause a problem I would think the wheels would skid.
We havent really timed how fast it picks up and how fast it drives. But from personal experience it picks up and scores the game objects pretty quick. And it can get from one isolation to the opposite in less than 10, with all the other robot interference. the only time we’ve experienced skidding was on regular flooring, wheres there is less friction, but on the game mats, there was no skidding at all.
Well the mat prevents it from skidding, but the sideways force is still there. I would recommend only driving the front wheels and switching the omni to the back and regular to the front as that should improve performance. But overall it looks like a very solid robot. Good job!
Unfortunately we were not able to film any of our practice and match videos. We haven’t had much practice with driver skills, but the highest we’ve gotten was 16.
However, there is the scores you guys can check on www.vexscores.com, for our match results. We were only competing in Oahu East Tournament and the Pan Pacific Championship.
How heavy is your robot?
Have you had any trouble with motors overheating or tripping breakers with the high speed configuration?
Just wondering because our robot is about 21 pounds and we were wondering about how we could speed it up (currently its 4 393s 1:1 with high torque config).
The only time we experienced overheating and tripping of the breakers, was when one of the motors on the drive was weaker than the other. We havent really weighed our robot so we dont know how much it weighs exactly. To speed up ur robot, i would suggest try replacing certain parts of the robot with aluminum metal, or u could try gear it up for speed, or u could just change the internal gearing of the 393 motors from high torque to high speed, also try using sprocket and chain on ur drive.
The rubber bands you use on the six bar arm seem to be pretty stretched out. Do they ever break or snap?
If they don’t, what rubber band brand are you using?
Also, I can see from this picture: aimimg_71 | Robot (Under side) | Gilbert Yim | Flickr , that the left quad encoder is being scraped ( there are some plastic scrapings on the encoder) by what I think is a shaftt collar. You should totally check if the mounting on the shift isn’t too tense.
Our rubber bands would occasionally break, but we would usually switch them out before it gets too stretched out. The scrapings u see, were caused by the collar that was holding the shaft in place, as the sprocket on the shaft was powered, the collar would spin on top of the encoder’s plastic cover.
