Pros and Cons of Suction Climb

Hi!My team is trying to decide how to do our climb for an off season event and so I was given the task to find info about suction climb and the calculation but I can’t seem to find any.Can you give me some info?

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Consider how it works. The outside atmosphere pushes down on the plate that holds the robot up. The pump will generally specify the amount of pressure it can reach. For this I will assume the pump can reach 5psi. The atmospheric pressure at sea level is 14 psi (it changes based on altitude and weather so look it up for your area and design a margin of safety). Thus for each square inch of your suction cup, there can be at most 14-5=9psi (can vary depending on setup). Then increase your plate area to match the weight of your robot. Do look at the center of gravity of your robot and how much of a lever arm you have.

Note that a bigger plate takes longer to engage and going with no safety factor will mean that you will fall.

To make it simple we made our suction plate 12x12 because this foam sheet comes in 12x12 https://www.mcmaster.com/1059n374

Some quick napkin math as PeterR explained confirmed that a pad this size could hold the weight of a sub 100 pound robot with ease (We designed the climber as a cheese cake so the robot we picked was going to be very light).

We had plans to simply move the pad further away from the fulcrum (increasing the lever arm) in the event that the robot was too heavy.

Quick and dirty, got the job done. We didn’t need to push of pad size because we were only going for a double climb and hab space wasn’t an issue.

I would consider successful implementing a suction climb in the offseason a high risk, high reward venture. If it works reliably, it’s a significant competitive edge. But if it doesn’t, you’re no better off than your started. I don’t know what team you’re on or its robot situation, but you may be able to get a lot of that valuable design experience with a lower risk venture, such as iterating on manipulators or a simpler climber.