Here is a pic of our design so far. This year, our ‘engineering’ help isn’t available and my background is architecture… thus the sleek design. Hopefully it works. I would appreciate any comments.
Some design specs are as follows:
Wheels will be custom made from aluminum, but we are looking into UHMW as a lighter medium. The wheels as pictured will weigh around 6 lbs each in aluminum, and around 2 lbs in UHMW. We don’t know if UHMW will work, so if anyone has any experience with the stuff, please comment.
Wheels are powered by four CIMS with Banebot planetary’s… ya, I know, they are not the trans of choice, but they are compact for this design, and they have not let us down yet. Keeping our fingers crossed !
The kicker is spring loaded, will be drawn back into loaded position with an FP motor/trans, released with leadscrew device. We wanted to stay clear of pneumatics as weight could be an issue. A rotary sensor is mounted to adjust the kicker for long & short ranges. The kicker (as tested in our halls) is able to move the ball 50ft through the air before landing. Quite powerful.
Ball magnet between front wheels (still testing, using 1-1/2" PVC coated with tool grip paint… I’ll update that later)
So far, the team does not want to attempt climbing for the 2 points. They feel that we will be able to score the two points to justify the decision. However, if they decide later to add something, the curved orange panels open up, similar to a ladybugs shell, to expose the inside mechanisms
The current design allows over the hump & through the tunnel travel, whichever will be of more benefit to the alliance.
Looking forward to some comments,
Cheers.
Very nice slick design. I like it, nice and simple yet effective.
Have you thought about buying those type of wheels from a place like AndyMark? (www.andymark.biz)
Yes, we have looked at AndyMark (several times) but it comes down to cost. We have great sponsor who has a 4 axis mill with indexing head to mill the aluminum/UHMW, and he will do the work as a sponsorship donation. Otherwise, the AndyMark wheels are out-of-pocket.
Thanks for the comment.
The mechanums are massive, 24 lbs for wheels? Maybe you can lighten them up a bit, swiss cheese style. Beyond that the design looks simple but effective, similar to the direction that my team is headed. As for your concerns with weight, I would be genuinely surprised if your bot weighed of 100 lbs but I do not know how your boy is constructed so i am not the best judge of its weight. My only concern is the lead screw, my team has used it before and had it fail. Just be careful with it, and test it a bunch. Better for it to fail in the shop then at a regional.
Be careful when going over the bumps with those wheels, if you go up at any sort of angle the vectors wont really work out and you’ll go in odd directions.
I like the swiss cheese thing. This is the first year that we have played with Inventor and I really like the iProperties screen. We have placed some holes in areas and have reduced the weight by a quarter, but again, I’m no engineer so I am not sure if its structurally sound.
Mom was right… I should have gone to university for engineering instead of architecture !
Not sure what the slot on top of the robot is for, but I would be careful; a ball that gets stuck in it may be considered carried. Sloping the top of your robot in some way along the long axis may alleviate this problem.
After you do the swiss cheese thing you can use stress analysis in inventor to see if it is still strong enough. Idk how exactly the stress analysis works, I will likely go ask my mentor for some basic tutorials.
I think that this year this is the most common type of design we’ll see. A robot that has rollers to hold the ball and then right behind the kicker mechanism is some sort of third class lever kicking mechanism, either powered by pneumatics or surgical tubing. Also 4wd mecanum seems to be a common topic on here this year so I’m suspecting we will definently see a lot of it coming up. Are you guys planning to use just normal tank drive or have you been looking at omni directional drives at all.
I think you actually should be fine. With the testing we’ve been doing with mecanums, the robot seems to straighten itself out before it actually starts going over if you hit it at the wrong angle. Obviously, you probably can’t go up sideways, but I’m pretty sure you won’t have too many problems otherwise.
