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2020 Day 5: "Sweet Spot" Parabola

Trajectory Calculators and the “Sweet Spot” Parabola 

For those of you that weren’t involved in FRC back in 2014, you may not be aware that Aren Hill, a friend of Spectrum, “invented parabolas.” During VEX’s Build Blitz that season Aren detailed a method of deciding on your shot trajectory by defining a wide “sweet spot”. The same principle should work this year.

During tonight’s meeting we did some analysis using two tools published on chiefdelphi to calculate the trajectory of the ball from a shooter. Thanks to CMarley, and Sam Geckler for posting these calculators.

The goal is to find a trajectory to limit the amount of variations you need in your shooting mechanism, while maximizing the distance range from goal for which you can still put the ball in the goal.

Basic idea, have the top of your arc at the top of the goal and a long flat tail on each side of the apex that still allows your ball to go into the goal.

Here are a few of the graphs we made tonight.
A wide range of distance that make it in the outer goal.

A similar shot in the other calculator
 
A shot that focuses more on the inner 3pt goal

If you can tune your shooter to fire every ball at a similar trajectory you may not need to adjust your velocity or angle as much as you think.

Robots That Inspired Us Today

2013 – 1114 (Dingus), 118 (Frisbee Angle Deflector)
2016 – 2056 (Simple adjustable rigid hood)
2017 – 33 (shooter/feeder), 1986 (Single Big Shooter Wheel)
2018 – 2877 (vision)
2019 – 148 (Climber Legs)
Source: Spectrum

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