View Single Post
  #2   Spotlight this post!  
Unread 16-01-2012, 01:41
Matt H. Matt H. is offline
Long Distance Mentor
FRC #1726 (N.E.R.D.S.)
Team Role: Alumni
 
Join Date: May 2006
Rookie Year: 2007
Location: Sierra Vista, AZ
Posts: 238
Matt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond reputeMatt H. has a reputation beyond repute
Re: Optimum Ball Mechanics

Quote:
Originally Posted by Jecht22 View Post
My 2 questions:
  1. what is the optimum gear ratio for shooting the balls (Direct drive using CIM's or gearing them up to go faster)
  2. What is the optimum angle to set the shooter at (fundamentally I see a 45 degree angle as the perfect angle to maximize distance but I wanted another opinion)
First welcome to the forums. Your question is hard to answer because optimum is a very fuzzy word. Do you want to maximize the distance the ball travels? Do you want to minimize the error in your shots? Your answers to questions like those will determine the optimal design.

For your first question:
The speed of the balls when they exit the shooter will be roughly proportional the the RPM of the wheels. For a physical model of the system see this post (also by me): http://www.chiefdelphi.com/forums/sh...ad.php?t=99797

The accuracy of your shots will depend on your system's control of the wheel RPM and the amount of symmetry you can build into your system.

It's often a good idea to gear your motors for peak efficiency, which in the case of the CIM means 4614 RPM at 45 oz-in of torque.

For your second question:
45 degrees gives the maximum distance in simple ballistics. There are many reasons to choose a different angle. For example depending on where your shooter is located on the robot, a 45 angle allows your shot to be blocked.
Reply With Quote