Team SCREAM's prototype robot

After three long hard weeks Team SCREAM finally has a working practice bot. We are now ready to assemble our competition robot.

Very nice.

Have fun with practice!

Nice! just a quick question, do you have problems with the ball falling out when you are driving? I noticed you had the white plastic sheets to keep it in, but is that enough?

what are the specs of your shooter?

Very impressive. This robot looks like it has the potential to be very, very successful at competitions. I have only one change to suggest.

Lose the meccanums. :slight_smile:

Bold added for emphasis. Seeing as this is one of the first complete robots (systems working together) to be posted except for the 72 hour builds, I would say you are doing just fine. That looks really great, and your field setup is really impressive. I wish we had that much space.

I noticed your robot had to pause and re-adjust where the ball was before it could shoot in the end. Do you see teams taking advantage of this and playing physical defense on you while you set up. This could be a problem, especially with the mecanum where they could easily push you around.

Thanks for the feedback and questions. We will do a more thorough reveal soon that shows all of the subsystems.

We are looking forward to having LOTS of driver practice with this robot. We have really discussed the pros and cons of the mecanum setup and we knew going into this we would have to give our drivers plenty of time to practice with it. Our drive base is also configured so that if we decided to we could easily swap them out for traction wheels.

In terms of the shields we are using 1/4" poly carbonate sheets to hold the ball in place. It actually works really well. We put a slight fold on the bottom so that it angles inwards to pinch the ball in place. It also has enough flex to let it fly out when we shoot. We have hit it pretty hard on all sides and the ball has been held tight.

Our shooter setup is a spring loaded catapult with a winch. The winch has an air cylinder to engage the window motor to pull it down. The only problem we have had with the winch is that it takes about 5 seconds to fully reset the catapult. We are testing out different pulley diameters to optimize the speed.

Finally, on the last shot our operator had to readjust the ball because he didn’t get it fully seated on the catapult with the collector arm. Ideally he will have this set in place before stopping aiming for the shot. These should be alleviated with driver practice. With our mecanum setup we will not be coming to a complete stop when shooting. Our trajectory on the ball gives us a lot of room for hitting the sweet spot.

If you have any more questions or comments please let us know. We will post more details soon…

I would love to see a video of the robot being hit “pretty hard” and seeing the ball stay in place. A slight pinch with those polycarbonate sheets is a pretty darn good idea IMO.

Also, are you worried about teams hitting your collector while you’re shooting? If I were playing defense on you that’s what I would do to turn your robot away from the goal.

Yes. We are worried about it. We understand the risk of the exposed arms and we will be bringing extras for sure in case of damage but it is a valid concern for us.

Wow, that looks awsome!

I have a couple questions:

  • Are you guys using just one cim per wheel or a cim and a mini-cim per wheel?

  • Do you like the Vex Pro 6in mecanum? I heard that when strafing the rollers lock up some times?

Good Luck with the rest of build season, Looking great so far!

We are using the toughbox nano from Andy Mark and have one cim per wheel.

So far we are really liking the VEX mecanums. I haven’t really noticed them sticking when strafing yet.

Very impressive, are you able to pass by just reversing the intake? And what cylinders are you using to lower and drop it?

Awesome work! Enjoy the driver practice and detailing time you have a head of you.


We have a couple of passing options. We can throw it over the truss for a long pass or we can reverse our pulley on the catapult to adjust the throwing angle for shorter passes as well. For a short pass or hand off we can reverse the wheels on the collector to release the ball.

We are using 6" stroke cylinders with a 3/4" bore.

Looks fantastic. With 2 weeks of driver practice on a full field and a live defender bot your drive team ought to be pretty polished come Arkansas. By the time we get to see you in KC the following week… should be amazing.

Curious as to how the refs will call the robot to robot contact. You were practicing against a really short defender, but someone of normal height would probably saddle you with a G28 for being bulldozed out of the way by an arm that hit them inside their frame perimenter. Not sure if G14 would apply if the defender initiated the contact. Should be a discussion point at the driver’s meeting before each tournament. Many robots will have that issue/non-issue.

That is a good point Aaron. We will look more into it. I foresee a LOT of robots with these style arms. It would probably be better if we shot out of the other end so we could keep the collector arm inside the frame perimeter.

I will search the Q&A and possibly post a question.

Looking awesome! All that driver practice will make you guys very competitive, great job.

Looking good Mike! We’re waiting on parts and hope to be together pretty well by this weekend. Nice practice set-up!

Thanks Brian. I hope you guys can come over and use the field with us.