Go to Post We treat productive freshmen the same way as everyone else. As for excesively ambitous new people, we have one rule:what happens in the hotel, stays in the hotel... ;) - Crop-Circles [more]
Home
Go Back   Chief Delphi > Competition > Rules/Strategy
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
 
 
Thread Tools Rate Thread Display Modes
Prev Previous Post   Next Post Next
  #7   Spotlight this post!  
Unread 20-01-2003, 08:35
Dodd Dodd is offline
Registered User
#0095 (Lebanon/Upper Valley Robotics Team)
 
Join Date: Jun 2001
Location: Lebanon, New Hampshire
Posts: 16
Dodd is an unknown quantity at this point
Joe's proposal

I think Joe's proposal for revising M11 is quite reasonable. I ran a couple of numbers in coming to this conclusion.

The power or rate of release criterion is no problem for applications of counterbalancing the weight of a mechanism, since the mechanism's motor does a reasonable job of defining and limiting the speed of motion. I was curious though about applications with less controlled rates of release - like flinging a container - so I looked at that.

Launching a container from the edge of one ramp at an angle of about 54 degrees above the horizontal at a velocity of about 26 ft/sec will allow the container to just clear a 5' tall 'bot on top of the platform and hit the field just at the end of the opposite ramp. The flight time is about 1.3 seconds. These numbers ignore aerodynamic effects and are idealized and approximate (but close).

I assumed the robot exerted a constant force (a la gas spring) on the container to accelerate it up to 26 ft/sec from rest along a 3' long path. The force required in this scenario is about 14 lbf, and the energy input (work done) is 42 ft-lbf. The time required to accelerate a 4 lbm container to 26 ft/sec with a 14 lbf net force is about 0.23 sec, so the rate of energy transfer to the container by the mechanism is 42 / 0.23 = 183 ft-lbf/sec ~ 250 w. I didn't check these numbers very well, but I think they are reasonable.

The point of all this is, I don't think that Joe's proposed numbers are restrictive of some crowd-pleasing robot design possibilities, while the original M11 numbers are onerously restrictive. BTW, I realize that M11 deals with energy stored at the beginning of the match, whereas any spring-powered multi-shot container launcher would have to recock itself by motor or pneumatic means during the match. I also realize that the rules restrict launcher powering to the use of elastic tubing, whereas I assumed constant force gas springs in my example for calculation ease. This was just to make sure that clever sheep on 47 wasn't slipping anything past all the rest of us.

Dodd
 


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
My Favorite rule. :) Useless member Rules/Strategy 15 01-03-2003 00:44
M11 and counterbalancing mechanisms... Joe Johnson Rules/Strategy 10 16-01-2003 21:47
Rule C1 Justin Stiltner Rules/Strategy 9 05-01-2003 22:59
Do away with the 2-minute rule! archiver 2000 3 23-06-2002 23:17
1 coach rule Mike Soukup Rules/Strategy 14 07-01-2002 22:27


All times are GMT -5. The time now is 19:32.

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