Well, if others getting better results perhaps it is only us. I'll answer your 
questions in case you have any more thoughts-


Each decision that the kids make in their robot  design matters.  Using the 
"knob wheel" as a  drive gear would be a bad idea for precision, while most of 
the "normal" gears work  quite well.
We're using the gears that the machine came with (the whilte and orange  ones) 
and didn't create any gear boxes ourselves.  (that made it into  the final 
robotic design)

  What kind of tires are they using?  Are they rigid or  bendable? 
We're using the 8.2 cm tires, the big ones, because the inch to .1  rotation is 
1 inch and a breeze to figure out when quickly updating the  robot.  Because 
we're using rotations and not distance or time, that  should increase our 
precision. Should. 

 Are they using crawler tracks? Nope.
  What kind of gear  ratios are they using?  1"=.1 roation
 Are they using programming techniques that  depend on consistent battery 
voltage? 

 Not to my knowledge. We're programming it to go straight certain  distances 
then turn, then go back or forward, and turn again.  Not  complicated stuff. 


 Is their chassis rigid or highly  flexible?
Chassis is rigid.  We have noticed that becasue of the length and  position of 
the back wheels, sometimes they can squeeze together  slightly and I try to 
remind the kids to open them up before sending it  out. But altogether, it 
should resemble a hard chassis. 

  Is the weight of the robot over the drive wheels or  offset? 
They fixed this by adding a counter weight  during the 5th week and  taking off 
a side mounted gear.  It was a hard decision and limited what  missions the kids 
could do, but ultimately it did lead to slightly  higher, but not perfected 
consistency. 

 Is the weight unevenly distributed?  All the rules of physics  apply and 
everything affects the outcome.
I can only say it's better and it was, so perhaps it's still the main  issue. I 
had asked a while ago if anyone knew of any programs or books  that would help 
with robotic design to counter some of these problems,  and ultimately I 
purchased a book to help me understand the basic  designs better and their pros 
and cons, but if you're not having the  same problems, then it MUST be our 
design. :(  Hope we'll figure it out  after the competition.  We're looking 
forward to seeing what all the  other robots look like :)


  Or that the spinning back wheel of the  classic "tribot" design can alter the 
the direction of the robot as it swings  around when you start to back up.
This design was abandoned in the 3rd week for a much more stable design that 
wasn't as twitchy. 


 
 Then  have them ask the robot designers of that team "How did you get your 
robot to be  so consistent?  What did you learn about inconsistency?  Did you 
use  any special parts that helped (e.g. different wheels)?"  The answers  will 
mean so much more to the kids coming from other kids rather than from  a book or 
coach, and they might get more excited about competing next  year with their 
new-found knowledge.
I will ask them to write down their observations.  ( I know at least two  or 
three of them will find this the best part of the competition.) 


 
I always tell my kids that their goal is to have  each mission work 9 out of 10 
times.  Their tendency is to try an idea once  and if it doesn't work to fiddle 
with it.  How do they know if that wasn't  the 1-in-10 failure and that the next 
9 times it would have worked great, unless  they tried it multiple times?  So 
even learning good engineering "process"  is something that produces consistency 
in the outcome.
They have been keeping a log to track data and the rule I asked them to  follow 
was no adaptations to the program until they had seen it run 3X  in a row.  Then 
fix it if it's still wrong.  


 
I hope your team can turn your frustration  into a quest for more knowledge and 
understanding.  After all, that's what  makes a great engineer!
Yes.  We are upbeat about all they have accomplished- the programming,  
research, teamwork.  I am as sunny as a summer day when it comes to what  they 
have accomplished and at the meetings, but afterward, I'm  disappointed I 
couldn't lead them to better answers.  Not give them  answers, that's worthless, 
but even send them in the right direction to  look around.  The pitfalls I knew 
about, I had lesson plans that taught  about it and had them experimenting to 
figure out the concept.  It was  great, but I clearly am lacking on the design 
side :(  It will be  fascinating to me to see one that works better than ours.  

Thanks, 
Brandy



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