Re: Ball Trajectory Planning
 

Ive worked on finding a good formula to make a good curve but to no avail. I think im just going to make a chart when our launcher is working what maps out various distances and initial velocities/theta. This way you can just either create a curve in labview or just store the data on the crio to have the code refer to

Re: Ball Trajectory Planning
 

Thats great news, I'm glad you went ahead and did a lot of research and posted it all here.

The information you are giving may be very vital to some of the games played this year!

Re: Ball Trajectory Planning
 

I hear from some of my basketball friends that you want to aim for the square on the backboard, and that will guarantee you a basket.

Assuming you are shooting a basket straight on, could you just calculate the normal angle of the plane that would give you the most area between the uppermost point of the backboard and outward most point of the hoop that would give you the greatest chance of scoring?

Re: Ball Trajectory Planning
 

I've been doing some basic physics on shooting the ball with near-optimal trajectory (still working on the equation for optimal trajectory) and have found that in some situations, essentially a full-field shot, ball initial velocities will need to exceed 10 m/s without accounting for air resistance (or spin, for that matter). As such speeds, wouldn't air resistance come into play?

Honestly, I'm doing this for fun without expecting accuracy, but I'd love to get as accurate as possible.

Ether, if you happen to be around, I'd love to get your input on this problem, since you know pretty much everything.

Re: Ball Trajectory Planning
 

Heh, thanks. I'm trying to get this whole cooperation thing though it goes against my extremely competitive nature :)

Re: Ball Trajectory Planning
 

You don't want to aim for the square on the backboard in general in basketball if you are shooting from a distance from in front of the rim. You aim for the backboard (and banking the shot in) when you are in close to and below the basket, particularly from the side. For shots from more than a few feet basketball players are taught to aim for the hoop itself and not the backboard.

Re: Ball Trajectory Planning
 

ooooh got it, thank you!

Re: Ball Trajectory Planning
 

http://hyperphysics.phy-astr.gsu.edu...traj.html#tra7

This should do work for you! Gives you everything you need to know. As long as you know the speed at which the ball is launched and the angle it will tell you how far it will launch. With some manipulations with the equation you can determine much other stuff also.

Re: Ball Trajectory Planning
 

The size and weight of the basketballs is listed in the rules in 2.2.11

here:
The Basketball is a Size 4 Compact foam basketball (Gopher Deluscious™ Foam Basketball, Item # 71-502) with an outer circumference of 25 in. and approximate weight of 11.2 oz.

Re: Ball Trajectory Planning
 

Ah, thanks, I totally missed that!

Re: Ball Trajectory Planning
 

All of our foam balls weigh ~10 ounces. That's gonna be a problem :(

Re: Ball Trajectory Planning
 

I am growing more and more convinced that any kind of consistent shooter will be rendered useless by the thoroughly inconsistent balls. :mad:

Re: Ball Trajectory Planning
 

Oh, here are some calculators for finding ball exit velocities and angles I put in a different thread.

Forum post

Re: Ball Trajectory Planning
 

This is all great and well, but unless they give us the equation somewhere to be used in our code, this is essentially rendered useless without creating a reference table for the robot. I'm working on getting the equation with some professors right now though.

Re: Ball Trajectory Planning
 

Using the viscosity of the air, I'm able to estimate the resistive force on the sphere (since it is a sphere, it makes this calculation much simpler instead of using the drag calculations.. which is okay, but i just prefer this one).. at 10m/s you will encounter significant drag.

Here's an Octave/Matlab script that does the estimation (working with iterative solution... no calculus involvement yet.. which seemed rather difficult to do)

https://bitbucket.org/ultimatebuster...12/bbairdrag.m