I was just wondering if any teams were opting for linetrack over dead reck or were adding that in as a demo ability for sponsors or anything.
Does any team plan on using a tote seeking ability, or have a working tote seeking program?
I believe the line seeker bots will fail. It would caus a hassle to do, but our team may, or maynot be using them…honestly I’m not sure.
Dead reckoning seems to be faster, easier, and more reliable. I haven’t yet seen a benefit of sensors, unless you count the cool factor. We probably will hook them up after the competition for demos and such.
I have no idea what all the strategies mean (like, what does dead reckoning mean your robot will do). But yea, sensors will scale high for the “Oh! Sweet mama! This bot follows this line…mommy, can I buy this toy?”
looking at all the variables in dead reckoning, we opted to make a line tracker, we use 6 sensors to do it, (3 per side) and we got it working almost 100% reliable and its quick, still in the tweaking but it works nice. with dr there are too many things that can go wrong, one wheel slips for a second and its off. just a little risky for us
Nice i get to see your 6 sensor linetrack at LI regional right?
Actually we are working on a intergration of both dead reck and line track into one code. Just wait… it’s gonna be good.
we have the capability to do both. six sensors? that would be nice.
we use 2 sensors to do line tracking. they are situated side by side towards the front of the bot. not saying anything else as far as exact location of the sensors !
anyone who wants at the events were at can come take a look at our sensors array. we have it set up differently for each side of the feild. we were having a little problem getting it to track the line like a conventional tracker, so we set up the sensors in a v formation, and enabled one side at a time depending on where we start on the field. from there it will go and only use one side driving it up to the ramp. then the gyro detects when we reach the ramp, wings come out, and we go full up the ramp slighty drifting into the middle by the time we get up to the top and take down a cool 5 stacks. our auto code programmer joe will be around if you have questions about the auto mode
I would think that a sensor on front, and 1 on back would be a better usage for them. The back detects a change of the line, and turns the right way if it is detected. Same with the front (this is if your front and back wheels drive independently)
*Originally posted by Raven_Writer *
**I have no idea what all the strategies mean (like, what does dead reckoning mean your robot will do). But yea, sensors will scale high for the “Oh! Sweet mama! This bot follows this line…mommy, can I buy this toy?” **
Dead reckoning is where the program tells the bot to go forward for X number of program cycles, then turn, then go forward again, then turn, then accelerate up the ramp and into the boxes 
You have to use trial and error to make sure you go the right distance and your turns are right.
The big problem is wheel slip. We have a dead reckoning program loaded, but we have it so it works on linoleum because we didn’t have enough carpet to test it. So the first practice match we are going to take off all the breakables, put on all the armor, and use that to tweak the program for carpet.
Another problem is colliding with another bot, but we figured that by the time you hit another bot you would be on the ramp and the line tracking wouldn’t help you any.
Actually we have sensors wired and mounted and a working line tracking program, but with our bot and strategy it is much faster and more reliable with dead reckoning.
I see few advantages with sensors and line tracking, but its a decision each team has to make based on their individual bot and strategy.
*Originally posted by Raven_Writer *
**I would think that a sensor on front, and 1 on back would be a better usage for them. The back detects a change of the line, and turns the right way if it is detected. Same with the front (this is if your front and back wheels drive independently) **
we have a 2 wheeled bot. 2 wheels in the back and skids in the front. we took that idea of 2 sensors, and just added a middle one. the rear sensor is right under the axel, mid sensor is about 3 inches out from that, and the front is more onto the corner making a v shape along the bottom of the bot.
dead reckoning - too inconsistent put a few bins in the way and while your robot thinks it is going straight up the ramp it is now going off at an angle. You get a battery that has a higher or lower charge the motors will act differently. just too inconsistent
Dead reckoning is where the program tells the bot to go forward for X number of program cycles, then turn, then go forward again, then turn, then accelerate up the ramp and into the boxes
:ahh:I don’t know what you’re talking about, but that would be a useless deadreckoning mode. the robot can travel in a curve much easier than in a rectangle. set one POT before the match and have it relate that number to a constant on one of the wheels. the code may look something like: (this is psuedo-code)
if (POT > 127)
right motor = POT + 127
left motor = 127
else
left motor = 393 - POT
right motor = 127
end if
or something like that. Just throw in the gyro, and test if it’s going up and step on it.
If you’re going towards the ramp with a bot that is knocked off greatly by bins, then perhaps the bot isn’t quite strong enough to attack the wall.
Then again, I could be completely wrong and victim of putting too much faith into dead reckoning. Time shall tell…
Out of curiosity, how long does it take on average for you line trackers to get to the top of the ramp? And are you having and problems once on the grill?
its faster to cut off the curve into 90 degree sections than to make a wide arc around to the ramp. If you use dead reckoning to make the same curve that you would if you followed the tape, what’s the point?
I agree that your code is simpler, but not faster, at least not for our bot.
We also were planning on putting the gyro in so it accelerates when it hits the ramp, but never got around to it. Yet another thing to be done at regionals.
*Originally posted by Stephen Kowski *
**dead reckoning - too inconsistent put a few bins in the way and while your robot thinks it is going straight up the ramp it is now going off at an angle. You get a battery that has a higher or lower charge the motors will act differently. just too inconsistent **
Yep. This is why we opted for a robot that follows the line. We’re using 5 sensors this year … they’re all lined up on the front of TOBOR VI. It’s pretty nifty!I believe we have a dead reckoning program written just in case we need to use it, but I’m not sure.
- Katie
Alex you are tired or really not with it. Where did you get 393? Actually I am not doing it like that at all. This is how I am doing it.
POT = (POT*127)/254 'Gives me a perportional number between 0 and 127
if POT<63 then
Left_drive = 127 + POT
Right_drive = 125 'Locks wheel
else
Left_drive = 125 'Locks wheel
Right_drive = 127 + (254 + POT)
endif
I think this is right but it is late and I can’t find the source I wrote earilier.
1
_______________
| |
| |
A B
2
____
_| |_
_| |_
| |
A B
maybe this will help explain what I’m trying to say. The distance from point A to point B is shorter in 1 than in 2
Edit- trying to get the lines right
Edit-close enough
First of all, we are not travelling in a straight line, we must travel forward, turn 90 degrees right, go forward, then travel 90 degrees right again.
Second, the distance may or may not be greater, that’s not the point. When you don’t do an arc, you have to stop, turn, then move, and then you have to accelerate back up to your top speed. When you do an arc, you apply power to the motors continously, and thus you aren’t jerky and you save some speed.
Now, it may be different depending on drive train issues, and robots, but it’s not as simple as “the shortest distance between two points is a straight line” (unless you are 179 and you can just climb over the rail, thus going in a straight line! :))
Stephen