Go to Post We build because we can. - Danaca [more]
Home
Go Back   Chief Delphi > Technical > Technical Discussion
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Closed Thread
Thread Tools Rate Thread Display Modes
  #16   Spotlight this post!  
Unread 16-01-2006, 11:56
BrianR BrianR is offline
Registered User
AKA: Brian Roehl
FRC #1525 (Warbots)
Team Role: Electrical
 
Join Date: Jan 2006
Rookie Year: 2005
Location: Deerfield, IL
Posts: 79
BrianR has a spectacular aura aboutBrianR has a spectacular aura about
Send a message via AIM to BrianR
Re: MAX ball shot trajectory

Quote:
Originally Posted by mathking
60 + 33.8 = 93.8 inches = 7 ft 9.8 inches = well below the goal.
Actually, as the goal has a 30" ID, the very bottom of the goal is at 7' 3".

Assuming that your calculation is for the center of the ball, which has a 7" diameter, it will extend 3.5" below the 7' 9.8", which brings you to 7' 6.3" at the bottom of the ball, which is above the 7' 3" bottom of the goal.

But if you were calculating for the top of the ball, you will have the ball hit the bottom of the goal by 0.2". Whether this makes it in is thus up to the spin you have on the ball, as frontspin would bring it into the goal, whereas backspin would cause it to fall away.

Oh, and another quick note. The goal is slanted forward at a 9 degree angle, which adds another variable into the calculations. Without doing all of the math, this will just make it harder for shots to hit after they have reached their maximum, and will make it slightly easier for shots which are still rising to go in. Just another little trick the GDC threw in to try to deter the really long shots.
  #17   Spotlight this post!  
Unread 16-01-2006, 12:18
Donut Donut is offline
The Arizona Mentor
AKA: Andrew
FRC #2662 (RoboKrew)
Team Role: Engineer
 
Join Date: Mar 2005
Rookie Year: 2004
Location: Goodyear, AZ
Posts: 1,314
Donut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond reputeDonut has a reputation beyond repute
Re: MAX ball shot trajectory

Something else teams may want to consider finding... there is a speed for every angle where the ball will "peak" inside of the goal range if fired at that speed. If you try to caculate to have the "peak" as close to the top of the goal as possible, but still able to go in, you get a range where the ball will go into the goal if you fire from anywhere within that range, so long as the angle and speed stay the same.

For example, if your ball leaves your launcher 54" above the floor, fired at 10 m/s and at a 32 degree angle, you can land the ball in the goal anywhere from 6' away to 24' away without having to adjust speed or angle.

That 9 degrees will just have to be accounted for then. I still think at least a few teams will be able to hit the goal from beyond the center line.
  #18   Spotlight this post!  
Unread 16-01-2006, 21:31
mathking's Avatar
mathking mathking is offline
Coach/Faculty Advisor
AKA: Greg King
FRC #1014 (Dublin Robotics aka "Bad Robots")
Team Role: Teacher
 
Join Date: Jan 2005
Rookie Year: 1999
Location: Columbus, OH
Posts: 642
mathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond reputemathking has a reputation beyond repute
Re: MAX ball shot trajectory

Quote:
Originally Posted by BrianR
Actually, as the goal has a 30" ID, the very bottom of the goal is at 7' 3".

Assuming that your calculation is for the center of the ball, which has a 7" diameter, it will extend 3.5" below the 7' 9.8", which brings you to 7' 6.3" at the bottom of the ball, which is above the 7' 3" bottom of the goal.

But if you were calculating for the top of the ball, you will have the ball hit the bottom of the goal by 0.2". Whether this makes it in is thus up to the spin you have on the ball, as frontspin would bring it into the goal, whereas backspin would cause it to fall away.

Oh, and another quick note. The goal is slanted forward at a 9 degree angle, which adds another variable into the calculations. Without doing all of the math, this will just make it harder for shots to hit after they have reached their maximum, and will make it slightly easier for shots which are still rising to go in. Just another little trick the GDC threw in to try to deter the really long shots.
Thanks for the correction. I had misread the arena dimensions and thought the the bottom of the goal was at 8' 6". My calculations were for the bottom of the ball. These are supposed to be the rough estimates which guide the engineering of the shooter. For example the decision of just what range in elevation to try for.

As for the 9 degree forward slant, the "quick" way to account for this is to assume a slightly smaller flat circular opening.
  #19   Spotlight this post!  
Unread 17-01-2006, 00:13
David Brinza's Avatar
David Brinza David Brinza is offline
Lead Mentor, Lead Robot Inspector
FRC #0980 (ThunderBots)
Team Role: Mentor
 
Join Date: Feb 2003
Rookie Year: 2003
Location: Glendale, CA
Posts: 1,379
David Brinza has a reputation beyond reputeDavid Brinza has a reputation beyond reputeDavid Brinza has a reputation beyond reputeDavid Brinza has a reputation beyond reputeDavid Brinza has a reputation beyond reputeDavid Brinza has a reputation beyond reputeDavid Brinza has a reputation beyond reputeDavid Brinza has a reputation beyond reputeDavid Brinza has a reputation beyond reputeDavid Brinza has a reputation beyond reputeDavid Brinza has a reputation beyond repute
Re: MAX ball shot trajectory

Here's a spreadsheet (that I've posted elsewhere) that allows the user to vary speed, angle, drag coefficient (Cd = 0.41 was measured), etc. The calculation includes air resistance and provides an x-y trajectory plot with the top and bottom of the goal opening indicated. Longest shot is definitely NOT the best trajectory...the parameters in the "as downloaded" shows a wide range for balls in the goal opening.
Attached Files
File Type: xls AimHigh_traj2.xls (78.0 KB, 99 views)
__________________
"There's never enough time to do it right, but always time to do it over."
2003 AZ: Semifinals, Motorola Quality; SoCal: Q-finals, Xerox Creativity; IRI: Q-finals
2004 AZ: Semifinals, GM Industrial Design; SoCal: Winners, Leadership in Controls; Championship: Galileo #2 seed, Q-finals; IRI: Champions
2005 AZ: #1 Seed, Xerox Creativity; SoCal: Finalist, RadioShack Controls; SVR: Winners, Delphi "Driving Tomorrow's Technologies"; Championship: Archimedes Semifinals; IRI: Finalist
2007 LA: Finalist; San Diego: Q-finals; CalGames: Finalist || 2008 San Diego: Q-finals; LA: Winners; CalGames: Finalist || 2009 LA: Semifinals; Las Vegas: Q-finals; IRI: #1 Seed, Finalist
2010 AZ: Motorola Quality; LA: Finalist || 2011 SD: Q-finals; LA: Q-finals || 2013 LA: Xerox Creativity, WFFA, Dean's List Finalist || 2014 IE: Q-finals, LA: Finalist, Dean's List Finalist
2016 Ventura: Q-finals, WFFA, Engineering Inspiration
  #20   Spotlight this post!  
Unread 17-01-2006, 16:47
VEN's Avatar
VEN VEN is offline
The future isn't what it used to be
AKA: Volodymyr
VRC #0478 (Mustang Robotics)
Team Role: Mentor
 
Join Date: Apr 2005
Rookie Year: 2004
Location: Richmond Hill, Ontario
Posts: 328
VEN is a name known to allVEN is a name known to allVEN is a name known to allVEN is a name known to allVEN is a name known to allVEN is a name known to all
Send a message via MSN to VEN
Re: MAX ball shot trajectory

We figured outa formula in excel...

so pretty much at12m/s and 45 degree angle the ball would go its highest at 3.7m and it would fall after 14.7 meters which means the shooter has to be at around 7.3m away from the target
Closed Thread


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Team 125 Ball Shooter Prototype! Brandon Holley Technical Discussion 21 21-01-2006 00:07
Ball Recirculation Question Nuts4FIRST Rules/Strategy 23 15-01-2006 15:35
Experimental Ball Drive Sepsis900 Technical Discussion 16 31-10-2005 16:59
2004 Game BBFIRSTCHICK General Forum 112 19-04-2003 17:12
Curie Division Robots information... (not complete) archiver 2001 3 24-06-2002 03:13


All times are GMT -5. The time now is 02:53.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi