Significance of drop center rocking on shooter accuracy

Our team has decided to go down the route of a flywheel shooting mechanism to launch Power Cells into the high goal this year. For the past 3 years, we’ve been building 6-wheel West-Coast-Drives with ~1/8" drop without a problem. They’ve always been reliable and relatively problem-free.

The possibility of the “rocking” effecting our shot accuracy came up, and using an 8 wheel drive with lifted outer wheels (to provide stability when stationary) was discussed as a possibility. We are looking to make a decision of whether or not we should stray away from the 6WD option in favor of more stability, but introducing more unknowns and complexity to our season.

In your experience, how much has the “rocking” of a 6WD drop center effected your shot accuracy? Is it worth straying away into an 8WD?

There’s a lot of math that goes into figuring out how much it will impact your shot. The rocking from one wheel to another is going to change your release angle, which will change the trajectory of the shot. How much it changes depends on the length of the robot and the amount of drop. How much it impacts where the ball will hit depends on the initial velocity and distance to the target. There’s no real substitute for doing the math, and you could get different answers from people that had different setups in previous games!

It’s a non-factor. You’re standing still when you’re shooting, and if you have any bias at all you’ll always be rocked to the same side at rest.

That said, if you want to be positively sure it will be a nonissue, do an 8 wheel drive or an asymmetrical 6WD with raised front.



Consider weighting your robot during design such that you spend the majority of your time (or at least your time not moving) on the rear wheels. Then, when you shoot, your robot has no where to rock.


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