Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

Yeah, one of our points in the video is to kind of hide the robot internals to an extent, but I'm happy to explain a mechanism to you. At one point we used two of the legal van door motors and two Banebot 775 geared on Versa Planetary Gearboxes at 100:1. They drive sprockets that are connected to the camshaft at about a 1:2 gear ratio (I cannot remember the exact numbers here). The cams were machined out of 1/4" aluminum and slide onto a Vex Pro hex shaft that runs across the entire mechanism working as the camshaft. I have attached some images that depict the original shape of the cams as well as the mechanism as a whole on the practice robot. Of course, it being a practice robot, we have removed one set of our 3D printed spacers to shorten them down because they added a bit too much unnecessary stress to the mechanism as a whole but this is not an issue on the competition robot (which was built much better). The reason I said the original design of the cams earlier in the post was because we added one slight notch on each side that allowed the catapult to rest slightly when cocked to lessen the stress on the van door motors. We actually learned that it was possible to remove those two motors entirely (the 775s were doing all the work anyway) and the small notches prevent any possibility of back-driving. If you have any other questions relating to the details of the mechanism, feel free to ask; I'd be happy to answer them.





It's not really all that faster, actually. The only change that was made was to switch a 12 tooth sprocket out for a 16 tooth so they could fit on a 1/2" hex shaft. The gearing farther down the line was changed to compensate (gearing was changed from 9.5:1 to about 9.3:1. The only real differences lie outside the drive train itself. This year's robot was designed to have an extremely low center of gravity (about 4" off the ground) which adds to an overall better drive base. Last year's robot was designed to have a 40 lb climber stowed away underneath, which when removed meant the robot was very tippy and had poor driving performance. Our 2014 robot also has improved programming for the steering modules (finding shortcuts for rotation of the wheels to prevent full 180 degree turns unless they are necessary, etc) and the parts were machined and assembled with a much higher standard in quality than in previous years. We really tried to put emphasis on building a finished product rather than what should be a complete prototype robot (we are currently fixing what would normally be our competition robot but is now our practice bot because we built two for this purpose). Our competition robot is built with an entire robot of experience behind us, so naturally it performs much better than even we expected of it!

P.S. To answer, we run at about 12-13 FPS in reality [geared for about 16 fps, but stress is a real thing].

Thanks for the questions, I hope I answered them fully! Please do not hesitate to ask any other questions about our robot, as we would be glad to answer them. I am more keen on answering mechanical questions and I'm sure Jefferson will be on top of any questions regarding the robot's programming time permitting.

-John Taylor Novak

Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

Wow. Hands down the most effective robot I've seen thus far.

Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

Normal speed. JT driving like a maniac. Sad no one has mentioned our double BFLs. ;)

Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

great looking robot! love the swerve...your team is the best around that does it!

question about the intake...how does the wheeled shaft interface with the lexan "arms"? looks like the shaft goes into a metal plate, that is in turn attached to the lexan. chain or similar running down to the robot to the motor? any close up pictures available?

Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

There is a 550 inside the beater bar. So all we have running up the arms are the motor leads.

Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

Wow. Best one robot I've seen so far. Awesome work

Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

Awesome, awesome, awesome!

We "borrowed" from your 2008 ball pick-up design and it proved to be most effective at the pre-bag scrimmage. Thanks for the inspiration!

Have a great year and see you in St. Louis!

Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

My only regret this season is I wont be able to see this robot in person. Another great robot by the Baxter Bomb Squad. I have seen all your robots in person since 2002, this one definitely beats all of them when it comes to efficiency and effectiveness.

Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

You can meet it in person if you make it to Nationals:p

Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

Nationals? What's that?

Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

It's a fun American party.

Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

Thanks for watching! I'll try to explain my best on how the beater bar mechanism works. As stated before, we use a BaneBot 550 motor that is actually mounted inside the bar itself for protection, ease of design, lowered machining times, weight, and overall cleanliness. I have attached some pictures of our CAD model below that provide a visual representation on how we fit the motor in the beater bar and how we interface the drive shaft of the motor with the bar. We machined round inserts that fit into the bar and are screwed in from the outside with flat head screws that have a hole in the center with clearance for a key so they can slip on the output shaft of the stock 25.91:1 BaneBot gearbox (it may be a different gear ratio, but I'd have to look at it to make sure). The motor/gearbox combination is attached to the poly-carbonate strips by two 1/8" stainless steel plates that capture the motor and a small aluminum block that both holds the assembly together and attaches it to the poly-carbonate frame component. The other end of the beater bar is simply held on by a small machined part that fits into a ball bearing on one end and interfaces with the Lexan on the other end via two screws. For purposes of illustration, I made the beater bar transparent even though it uses our Baxter blue livery in the real world.



-John Taylor Novak

P.S: Unfortunately, I don't think I am able to give CAD models until the season is over due to the nature of the competition, but I'm more than happy to provide pictures of the models for a rough reference to the overall idea. :)

Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

Wow, that's quite a cool concept! The last time I've been this excited is when I found out how your swerve drive works:D Innovative ideas as always!

Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

That 3 ball autonomous mode is awesome! I hope my team gets to our goal of a 2 ball autonomous before our week 1 competition

Re: Baxter Bomb Squad 2014 ~ Nighthawk
 

Nice to see this thing finally public. Hopefully I'll be able to stick my head inside and talk swerve with you guys at CMP this year.