Methods of adding ballast to underweight robots

[Team 135]

I know at the midwest regional there was a team filling water bottles with sand. This is a great way to do it because you can evenly distribute the weight across the bot.

[EricH]

At L.A., one of the robots we reinspected for eliminations had made a modification: They'd put diving weights on their robot as ballast. They're in Sacramento this week, probably with said weights still aboard.

[Al Skierkiewicz]

Originally Posted by Team 135

I know at the midwest regional there was a team filling water bottles with sand. This is a great way to do it because you can evenly distribute the weight across the bot.

Anthony,
Yes, that was the case, but the teams in question had to add additional material to satisfy the lead inspector, namely sealing the bottles with super glue, wrapping entirely with layers of tape and mounting in a very secure manner inside the frame of the robot where they could not be touched by robot collision. Repeated trips to the pit to re-examine the ballast were required as even a small amount of sand would have changed the frictional forces of the floor. In looking back, I am not sure that was the best decision. Although there were no spills, I felt uncomfortable about it the rest of the weekend.

[Team 135]

Originally Posted by Al Skierkiewicz

Anthony,
Yes, that was the case, but the teams in question had to add additional material to satisfy the lead inspector, namely sealing the bottles with super glue, wrapping entirely with layers of tape and mounting in a very secure manner inside the frame of the robot where they could not be touched by robot collision. Repeated trips to the pit to re-examine the ballast were required as even a small amount of sand would have changed the frictional forces of the floor. In looking back, I am not sure that was the best decision. Although there were no spills, I felt uncomfortable about it the rest of the weekend.

Thank you for that clarification, I knew that they did it, but didn't know how that looked from an inspection standpoint.

[Al Skierkiewicz]

For anyone reading this, any modification to the robot after the initial inspection requires a reinspection even if you are removing something. All inspectors would prefer that you contact them prior to making changes especially adding weight. Inspectors have a variety of ideas on specific changes and their impact on your robot and team play. Adding weight of the type described (kitty litter, sand, shot, ball bearings, etc.) should be discussed with the inspector prior to adding them even before your initial inspection. Inspectors need to discuss these things with the FTA and Head Ref as well so there is no surprises when you get on the field. Again a reminder on lead of any kind...it must be sealed (i.e. painted, dipped, etc.) prior to bringing to an event and may not be machined in the arena, i.e. no drilling, cutting, filing or breaking.

[Aren_Hill]

The route we have went this year was by using 3/4" threaded rod with large washers on it, then just fine tuning the number of washers. They are solidly bolted down and cant really make a mess so it works well.

[jgraber]

Originally Posted by Tazlikesrobots

At the Dallas regional, there was a robot that used bags of cat litter for ballast. Basically it was a driving chassis with one of the kt tubs attached and two 20 pound bags of cat litter inside the tub.

They got the judges award

My recollection is that another rookie team with drive chassis, barbell weights, and a small scoop+kicker wheel got the judges award;

The Kit Tub bot rookie team was #3 alliance leader.

[Tazlikesrobots]

Originally Posted by jgraber

My recollection is that another rookie team with drive chassis, barbell weights, and a small scoop+kicker wheel got the judges award;

The Kit Tub bot rookie team was #3 alliance leader.

You are correct! I got the teams mixed in my head.... the team with the cat litter box took highest rookie seed!