Subject:
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Re: Competitive MINDSTORMS: Now in a store near you!
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 19 Aug 2004 17:48:53 GMT
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Viewed:
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1092 times
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In lugnet.robotics, Steve Hassenplug wrote:
> In lugnet.announce, David Perdue wrote:
> > After more than a year since its conception, I am proud to announce the
> > completion and publication of Competitive MINDSTORMS: A Complete Guide to
> > Robotic Sumo Using LEGO MINDSTORMS.
>
>
> David,
>
> I was looking over the robots & code listed in your "bonus chapters", and I must
> confess, I'm a bit disappointed. Maybe I'm missing something, but I'd be
> interested to know how these robots have actually done in competition.
>
> Maybe you can help me out, by explaining how this search task (written for
> Brain-Bot-ZR1 from Bonus Chapter 2) is designed to work...
>
> ------------
> /* This task searches for the other
> * sumo-bot with a second light sensor*/
> task Search()
> {
> // second highest priority
> SetPriority(1);
>
> while(true) // infinite loop - always check for sumo-bots
> {
> until(LBump<=thresh); // until sensor detects sumo-bot
>
> acquire(ACQUIRE_USER_1) // get control
> {
> Wait(CALIBRATION); // wait a little
>
> /* if Input Port 1 is less than "thresh" or
> * equal to 100*/
> if(LBump<=thresh | LBump==100)
> {
> BL = 1;
> BR = 1;
> SwitchSTurn(); // if true, go on slow speed and...
> speed = 1;
> Forward(); // ...attack!
> until(LBump==thresh+5); // until sumo-bot goes away
> SwitchF(); // stop attacking
> speed = 0;
> BL = 0;
> BR = 0;
> PlaySound(SOUND_UP);
> }
> }
> }
> }
> -----------
>
> I know LBump is the left touch sensor & forward-facing light sensor. And thresh
> gets it's value from LBump, when the robot is calibrated. But, I don't see this
> task as something that will do a lot of good.
>
> So, how well does it work?
>
> Thanks
> Steve
Hi Steve,
I think I see where you're getting confused. Summed up, some of the concepts
presented in this chapter build upon Chapter 6 in Competitive MINDSTORMS, so
it's important to understand the concepts in that chapter before reading the
bonus chapter. The most important concept to understand is that once the
searching light sensor has detected the opponent, Brain-Bot switches to slow
speed. Brain-Bot has a fast speed of 1:15 and a slow speed of 1:75 - this is why
it is so important to switch to slow speed, because it gives ZR1 so much pushing
power.
So let's look at this portion of code:
/* if Input Port 1 is less than "thresh" or
* equal to 100*/
if(LBump<=thresh | LBump==100)
{
BL = 1;
BR = 1;
SwitchSTurn(); // if true, go on slow speed and...
speed = 1;
Forward(); // ...attack!
until(LBump==thresh+5); // until sumo-bot goes away
SwitchF(); // stop attacking
speed = 0;
BL = 0;
BR = 0;
PlaySound(SOUND_UP);
}
}
}
}
So once LBump has detected the opponent, ZR1 switches to slow speed with
SwitchSTurn()--which is the important part--and stays like that until it loses
sight of the opponent. The whole task, and essentially a major part of ZR1's
sub-strategy, rely on the switching to slow speed. So essentialy, if you take
away the ability to switch to slow speed, ZR1 can almost virtually say goodbye
to any sumo success! All those gears you see make up a complex transmission
which do the switching - all this is discussed in Chapter 6 of Competitive
MINDSTORMS.
Thanks,
David J. Perdue
www.davidjperdue.com
www.davidjperdue.com/competitivemindstorms
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Message has 2 Replies:
 | | Re: Competitive MINDSTORMS: Now in a store near you!
|
| (...) Right. I can see the two motors connected to port B will slide the axles and switch the drive train from "fast" to slow. (...) ...But I don't see how LBump will detect the opponent. Or better yet, how does it know when it loses sight of the (...) (20 years ago, 19-Aug-04, to lugnet.robotics)
| | | Re: Competitive MINDSTORMS: Now in a store near you!
|
| (...) By "speed", do you mean those are the gear ratios? What is the mass and wheel radius for Brain-Bot? And how many driving motors does it use (i.e., how many motors actually apply torque into the drive train, as opposed to shifting gears for (...) (20 years ago, 19-Aug-04, to lugnet.robotics)
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Message is in Reply To:
| | Re: Competitive MINDSTORMS: Now in a store near you!
|
| (...) David, I was looking over the robots & code listed in your "bonus chapters", and I must confess, I'm a bit disappointed. Maybe I'm missing something, but I'd be interested to know how these robots have actually done in competition. Maybe you (...) (20 years ago, 19-Aug-04, to lugnet.robotics)
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