Re: 1747 Harrison Boiler Robotics: Sea Cobra
 

This was my personal favorite robot of Premier Night. Brilliantly simple and effective design. Awesome work!

Re: 1747 Harrison Boiler Robotics: Sea Cobra
 

In regard to the posting of the chat from Top25 Premier Night there were a few questions about the robot.

Weight was one I saw I couple of times. The robot is currently 116 lbs, but we will be adding a few things that will probably take it right up to 120. Our bumpers should also end up right at 20 as well. With the robot as fast as it is, we need to keep the center of mass nice and low, which the bumpers help with immensely.

The robot will be getting more air storage and a pair of static polycarb arms to help with catching and keep the ball retained when the pickup introduces it to the interior of the robot in a vigorous way.

In regard to the duct tape on the ball. That was our kit ball that was used for prototyping. A few of the prototypes damaged the ball significantly. The rollers have left some fine debris on the other balls we practiced with, but never any permanent marks. The silicone on the shooter roller has been a great choice and we may have to move to that for the pick up as well.

Shooting speed is something else that I saw brought up. The team will be making an adjustment on Thursday at CIR that will hopefully speed that process up. We accelerated significantly by playing with the combination of air pressure, flow restrictors, and solenoid actuation timing. Bottom line: it should be significantly faster at CIR.

A word about the wheels. They are VexPro 6" diameter by 2" wide traction wheels with blue nitrile inclined conveyor belting attached with the appropriate alligator lacing and several fasteners along the circumference of the wheels. We have found that contact patch definitely matters experimentally speaking. The wider and larger diameter wheels provide a significantly larger observed contact patch and therefore much more traction. (not intended to start a debate, this was experimental observation)

I cannot express how much the team appreciates the kind words and compliments. We are very excited and wish everyone the best of luck at competition.

Re: 1747 Harrison Boiler Robotics: Sea Cobra
 

Not to nit-pick too much... but the whole field in 3.25s? Are we talking width or length? I would love to see a video of that.

I'm with everyone else: very cool shooter.

I also heartily approve of your wheel and tread selection, especially the reasoning behind your decision re: contact patch.

Re: 1747 Harrison Boiler Robotics: Sea Cobra
 

The reveal video posted on YouTube shows the robot going from one end of a room to the other (from 33 to 36 second marks). The room is just a bit larger than the field will be.

We have not tested an actual 'wall to wall' time, but the top speed of the robot is just over 17 fps.

Re: 1747 Harrison Boiler Robotics: Sea Cobra
 

But you're talking width-wise, not length-wise. Which makes the claim of 3.25s much more believable.

Re: 1747 Harrison Boiler Robotics: Sea Cobra
 

It's actually 3.25s to cross 45', because that is realistically "crossing" the field from our perspective at least. With the auto shifting 2 speeds and 6 cims the acceleration is unbelievable. Take a gander at the CIR webcast and we'll show it off at some point I'm sure.

**Edit** The video doesn't do the driving performance justice. The space we were testing in is very close to the size of a field. **Edit**

Re: 1747 Harrison Boiler Robotics: Sea Cobra
 

That's why I want to see video of it! ;)

Re: 1747 Harrison Boiler Robotics: Sea Cobra
 

Soon... Thursday we'll be at CIR and will have a chance to demonstrate our power. <insert Jeremy Clarkson :ahh:>

I'll also be sure to have someone record us going top speed from end to end.