I'm hoping to cover this topic in a future video. Everything I know about the PID algorithm came from a totally awesome article written by J. Sluka. Simply google "PID NXT Line Follower Sluka" to find it. This article is for using PID in a line follower. Apply the same ideas taught in this article to the going straight problem (the error term is the difference between two rotation sensor readings). We implemented a "PI" algo and got increased performance over P algo, but PID didnt work well
Im in grade 4 and in our school we have this thing for juniors to join and make something cool out of lego. If your thing is really good you get to go to Toronto to COMPETE over lego things you design. I was thinking of a robot so
Check out this video about the 2012-2013 Robotics FLL Challenge for some NEW Info on Senior Solutions by typing in 2012 Robotics FLL Challenge -it is by thepricklypear65
Smart! But if you really want to go 99,9% straight you might want to try a differentalgear system as seen in many lego tank constructions over youtube.
The only thing to worry about then is the wheels diffrence in size!
Hello! I really like your robot design! Do you have a guide on how to build it for my FLL team? Thanks!!!! :) Also where do you find those tall Technic wheels?
Sorry that robot has been taken apart, and I don't have anything other than the video. Pause the video at 1:53, that should give you a good idea of most of the design. The Wheel/Tire are lego part 2902 and 2903. Buy them on bricklink. The design is quite simple. Just mount length 15 beams to the top of the NXT brick, then mount the motors to the beams. Then used the 3x7 bent liftarms to mount between the two white connection points on the motor and mount the back wheels to it
Thats a nice long innovative way, but what we did was we just put stickers lined up on our wheels and ran them for about 10 rotations. Then we looked at the placements of the stickers to determine if the motors matched or not.
I need instructions on that motor testing program. I couldn't copy it from the video . Do you think you could make a video on how to program it? That would be great! I have been doing a FLL robotics team for 2 years (This year is my second) and last year one of our problems was not going straight.
Thank you for your help! I just matched our best pair of motors out of 27! Whew! I made a video similar to yours (and gave you credit for the process).
So now the question is after you've got that prime set of motors, do you verify them running them head to head simultaneously? We found in our 1st round of testing that our results were skewed by our battery weakening. hastypete made the suggestion of running the tests with the battery charger plugged in. We did that and only began a test when battery was indicating full charge too. The seond round found us some good pairs (verified by running them simultaneously!)
@TheFLLCoach thanks:) and so you are aloud to use blocks other than what is given? I have a friend who has tubs and tubs full of legos. Could we use those? And what grade is your team in this year? Thank you!:)
Im just not starting fll this year and im in 9th grade i had no idea what it was about or what to do until today! This all seems pretty complicated. How is it that u have the mat and the peices for this years challenge? Also you already have your car made? Ive just now learned about this and im not sure if i will be able to make a robot as good as this one. Any advise.
It is pretty complicated. There are books out there to help get you up to speed quickly. I like 'Winning Design by Trobaugh.' We have our mat because our team registered early. Building these robots takes practice and you need to learn how to work with the available LEGOs. Our team buys a lot of LEGO from sellers on bricklink because what comes with one kit is not nearly enough. Google 'nxtprograms' to find example robot designs.
Try using software techniques too... in my team we put a lot of effort in the software to make the robot drive straight.
The point is to check the difference between the motors while it is driving (if motor B drove 255 degrees and C drove 250, there is a 5 deg difference - obviously the robot is not driving straight. Then, the program reduces power from B and adds to C. This runs in a loop while the robot drives. That's the concept- use it and your robot will drive even better!
Yes, our team does use software to make our robot monitor and correct the motion as it drives. Our algorithm is basically to proportionally reduce the power of the motor that's going too fast based on the difference between the rotation sensors. The move block uses a little bit more advanced algorithm called Proportional Integral Derivative (PID). This algorithm does a pretty good job of correcting for unbalanced motors.Yes, you can probably get better if you made your own PID
Even with software correction (which the MoveBlock already does) it still would be better if your motors were well matched; so you are relying less on the algorithm to correct for a bad situation. Think if you had two horses harnessed together and one of them always wanted to run faster than the other. Yes you could keep correcting each horse to get them to stay in sync, but it would be easier if the horses just naturally stayed in sync so you wouldn't need to always correct em
This is an excellent suggestion. I think we'll repeat all of our testing with the battery fully charged and the charger plugged in. Thanks for the Excellent comment!
It has MyBlocks which don't share well. We made a MyBlock with two inputs: power(number) and direction (logical). The MyBlock simply has 3 cascaded loops and prior to each timer 1 is reset. Each loop has a motor blk set to infinte dur and will be exited when the rotation sensor equals 3600 and then Timer1 will be read and stored to a variable. The three time are averaged and used as an output of the MyBlock. the main program calls the MyBlock for 8 cases and displays results on NXT
Sharing is easy with myblocks. Just use "Pack and Go" under the tools menu. It makes a single file that contains all necessary myblocks. When you load this file, all the my blocks are installed for you. it seems easy enough to figure out for most teams and a good exercise anyway.
No same camera. We recorded the segments over periods when it was light and dark outside. When we're filming with artificial light, everything looks yellowish to our camera.
I'm hoping to cover this topic in a future video. Everything I know about the PID algorithm came from a totally awesome article written by J. Sluka. Simply google "PID NXT Line Follower Sluka" to find it. This article is for using PID in a line follower. Apply the same ideas taught in this article to the going straight problem (the error term is the difference between two rotation sensor readings). We implemented a "PI" algo and got increased performance over P algo, but PID didnt work well
TheFLLCoach 1 week ago
Hi, could you explain the PID algorithm?
Our team made something similar that makes the two motors move at the same rate and it's very efficient but I'm interested in this algorithm.
merolizer 1 week ago
how did you build the "smart move" blood?
sagivoulu 2 weeks ago
Im in grade 4 and in our school we have this thing for juniors to join and make something cool out of lego. If your thing is really good you get to go to Toronto to COMPETE over lego things you design. I was thinking of a robot so
thx!
Yusra1001 1 month ago
This has been flagged as spam show
Check out this video about the 2012-2013 Robotics FLL Challenge for some NEW Info on Senior Solutions by typing in 2012 Robotics FLL Challenge -it is by thepricklypear65
thepricklypear65 1 month ago
what algrim you talking about, can u explain further about the program please, thanks
VIadmirLenin 2 months ago
thr programming is hard
VIadmirLenin 2 months ago
This is very informative. You have enlighten me on the robot design. Thank you.
shimmerygirl 2 months ago
what is the robotics software called
dinoyan5 3 months ago
what is the robot porgrame
dinoyan5 3 months ago
my team is the robonauts and we r going to state
thesnvman 3 months ago
Smart! But if you really want to go 99,9% straight you might want to try a differentalgear system as seen in many lego tank constructions over youtube.
The only thing to worry about then is the wheels diffrence in size!
dacke93 3 months ago
i won my fll scrimige/tourny!
111111SHADO 4 months ago
Really great!
Very useful instructions on how to make one's robot go straight.
Can you post a video on how to track lines also?
onion013 4 months ago
Nice job! Very clear and helpful video.
Good luck with Food Factor!
batterup98 4 months ago
Hello! I really like your robot design! Do you have a guide on how to build it for my FLL team? Thanks!!!! :) Also where do you find those tall Technic wheels?
cvarlamo 5 months ago
@cvarlamo
Sorry that robot has been taken apart, and I don't have anything other than the video. Pause the video at 1:53, that should give you a good idea of most of the design. The Wheel/Tire are lego part 2902 and 2903. Buy them on bricklink. The design is quite simple. Just mount length 15 beams to the top of the NXT brick, then mount the motors to the beams. Then used the 3x7 bent liftarms to mount between the two white connection points on the motor and mount the back wheels to it
TheFLLCoach 5 months ago
@cvarlamo the funnest part of building a robot for fll is well COMING UP WITH YOUR OWN IDEA;)
fishy320 4 months ago
@cvarlamo i took part in a tournomant yesterday in bristol we where cheated!:( it was very annoyingbecause we would of won!!
mrjackcampbell1 3 months ago
Hello! I really like your robot design! Do you have a guide on how to build it for my FLL team? Thanks!!!! :)
cvarlamo 5 months ago
Thats a nice long innovative way, but what we did was we just put stickers lined up on our wheels and ran them for about 10 rotations. Then we looked at the placements of the stickers to determine if the motors matched or not.
ekameka56 5 months ago in playlist More videos from TheFLLCoach
Great work! This is a very good video and process. I bet your robots go really straight. well done.
fllcoach0broadacres0 5 months ago
I need instructions on that motor testing program. I couldn't copy it from the video . Do you think you could make a video on how to program it? That would be great! I have been doing a FLL robotics team for 2 years (This year is my second) and last year one of our problems was not going straight.
Hayden1232001 5 months ago
thanks you helped me much
luavcbef 5 months ago in playlist Lego Robotics - Food Factor
Great Tips on keeping the robot straight and selecting 2 well matched motors. Thanks so much for sharing !! Good Luck !
gravya 5 months ago
Thank you for your help! I just matched our best pair of motors out of 27! Whew! I made a video similar to yours (and gave you credit for the process).
andrewdenio 5 months ago
@andrewdenio
So now the question is after you've got that prime set of motors, do you verify them running them head to head simultaneously? We found in our 1st round of testing that our results were skewed by our battery weakening. hastypete made the suggestion of running the tests with the battery charger plugged in. We did that and only began a test when battery was indicating full charge too. The seond round found us some good pairs (verified by running them simultaneously!)
TheFLLCoach 5 months ago
@TheFLLCoach thanks:) and so you are aloud to use blocks other than what is given? I have a friend who has tubs and tubs full of legos. Could we use those? And what grade is your team in this year? Thank you!:)
mromar53 5 months ago
@The
mromar53 5 months ago
Im just not starting fll this year and im in 9th grade i had no idea what it was about or what to do until today! This all seems pretty complicated. How is it that u have the mat and the peices for this years challenge? Also you already have your car made? Ive just now learned about this and im not sure if i will be able to make a robot as good as this one. Any advise.
mromar53 5 months ago
@mromar53
It is pretty complicated. There are books out there to help get you up to speed quickly. I like 'Winning Design by Trobaugh.' We have our mat because our team registered early. Building these robots takes practice and you need to learn how to work with the available LEGOs. Our team buys a lot of LEGO from sellers on bricklink because what comes with one kit is not nearly enough. Google 'nxtprograms' to find example robot designs.
TheFLLCoach 5 months ago
What grade are u in?
mromar53 5 months ago
What grade are u in?
mromar53 5 months ago
Thanks!
TheFLLCoach 5 months ago
Wow - your team is a mine of knowledge. Great presentation.
Iamcrazyken 5 months ago
very nice video. thanks much!
hectorkatz 5 months ago
great advice for choosing the best parts from our supply.
geocad10 5 months ago
Try using software techniques too... in my team we put a lot of effort in the software to make the robot drive straight.
The point is to check the difference between the motors while it is driving (if motor B drove 255 degrees and C drove 250, there is a 5 deg difference - obviously the robot is not driving straight. Then, the program reduces power from B and adds to C. This runs in a loop while the robot drives. That's the concept- use it and your robot will drive even better!
MozartJunior22 5 months ago
@MozartJunior22
Yes, our team does use software to make our robot monitor and correct the motion as it drives. Our algorithm is basically to proportionally reduce the power of the motor that's going too fast based on the difference between the rotation sensors. The move block uses a little bit more advanced algorithm called Proportional Integral Derivative (PID). This algorithm does a pretty good job of correcting for unbalanced motors.Yes, you can probably get better if you made your own PID
TheFLLCoach 5 months ago
@TheFLLCoach We use PID too... using it and planning the robot well is the key to a straight robot.
MozartJunior22 5 months ago
@MozartJunior22
Even with software correction (which the MoveBlock already does) it still would be better if your motors were well matched; so you are relying less on the algorithm to correct for a bad situation. Think if you had two horses harnessed together and one of them always wanted to run faster than the other. Yes you could keep correcting each horse to get them to stay in sync, but it would be easier if the horses just naturally stayed in sync so you wouldn't need to always correct em
TheFLLCoach 5 months ago
Your Team Rocks!!!! Thanks for great information.
Medbots1 5 months ago
great job!
andrewdenio 5 months ago
what kind of motor does it use (sorry if you say it later in the video, i havent seen it all yet)
charmanderstail 6 months ago
@charmanderstail
We're using the motors that come with the Mindstorms kit. LEGO refers to them as:" 9842 Interactive Servo Motor"
TheFLLCoach 6 months ago
You should get a rechargeable NXT battery pack and use it plugged in to make sure that your running voltage is always consistent.
hastypete 6 months ago
@hastypete
This is an excellent suggestion. I think we'll repeat all of our testing with the battery fully charged and the charger plugged in. Thanks for the Excellent comment!
TheFLLCoach 6 months ago
do you share the testing program??
luavcbef 6 months ago
@luavcbef
It has MyBlocks which don't share well. We made a MyBlock with two inputs: power(number) and direction (logical). The MyBlock simply has 3 cascaded loops and prior to each timer 1 is reset. Each loop has a motor blk set to infinte dur and will be exited when the rotation sensor equals 3600 and then Timer1 will be read and stored to a variable. The three time are averaged and used as an output of the MyBlock. the main program calls the MyBlock for 8 cases and displays results on NXT
TheFLLCoach 6 months ago
@TheFLLCoach
Sharing is easy with myblocks. Just use "Pack and Go" under the tools menu. It makes a single file that contains all necessary myblocks. When you load this file, all the my blocks are installed for you. it seems easy enough to figure out for most teams and a good exercise anyway.
hastypete 6 months ago
that is a brillant method im going to do this with my 4 NXT´s
luavcbef 6 months ago
did you use two different cameras?
shmlu 6 months ago
@shmlu
No same camera. We recorded the segments over periods when it was light and dark outside. When we're filming with artificial light, everything looks yellowish to our camera.
TheFLLCoach 6 months ago
Go JJ!
shmlu 6 months ago