martinnygaard Posted December 30, 2012 Posted December 30, 2012 (edited) Hi all LEGO lovers! I've bought this Mindsensors LineLeader sensor some weeks ago. But i'm not really satisfied with the result. The veichle zig-zag a lot, and i saw some videos of this sensor at Youtube (like Xander's) but my result is net even close to his. A picture and a video will come soon. my question is; What is your experiences of the sensor? is there a minimum wheel size, for making it work properly? maybe the sensor has to be a minimum distance from the driveaxle? Hope some of you guys can help me - need it to drive 100% correct all the time, 'cause the veichle will drive UNDER a table at LEGO exhibitions. Edited December 30, 2012 by martinnygaard Quote
DLuders Posted December 30, 2012 Posted December 30, 2012 @ martinnygaard: There is some good advice on how to "Calibrate" your Lego Mindstorms NXT Line Follower at the bottom of this NXTprograms.com webpage. There are some useful downloads, and many YouTube videos, on this Mindsensors.com webpage for that NXTLineLeader device: Quote
martinnygaard Posted December 30, 2012 Author Posted December 30, 2012 Carsten, The gain Values, is that the 8 values from the sensors? The black line is 0 excatly and white is between 40 and 100. The sensor is calibrated after the instrutions. I use electrican isolationtape for the black line. But itøs the same result at the TestPad from Mindstorms. Quote
Carsten Svendsen Posted December 30, 2012 Posted December 30, 2012 I just saw the video you posted and assumed you must have seen some gain values (Kp, Ti, Td) in the programs. Which programming language are you using? I have downloaded the NXT-G program block and it doesn't offer many solutions/possibilities. RobotC on the other hand offers loads of possibilities and this is where you choose your gain values. Download the demo and lib files from here and you will notic it straight away. You're an electrician just like me, so I assume you know everything regarding PID-controllers A video of how you robot performs now would be perfect because right now, it's almost impossible to say which settings are in need of a change. Quote
martinnygaard Posted December 30, 2012 Author Posted December 30, 2012 Nope, i'm totaly new in PID-Controllers - unfortunatly we havn't heard anything about that yet, in school (Electrician education) - and when i read about it at Wikipedia, it sounds complicated. So i use the simple "Follow the line"-block in the NXT-G software. I've already spend my trail-period in RobotC, and i find it very simple and usefull. (Because of my self-learned webside designer experiance) but i just not have the credit for buying a licens right now. as said in first topic, a video will come - maybe tomorrow, if i find the time. Quote
martinnygaard Posted January 11, 2013 Author Posted January 11, 2013 now i got the RobotC programming - and understand the PID. But i can't figure out how to change the PID-values en the "sample files" from Mindsensors i RobotC? Anyone who can help? Quote
Carsten Svendsen Posted January 12, 2013 Posted January 12, 2013 See line 100 in LL-lib.c for an example. You have to exchange "byte" with a number you prefer. Also read the info in LL-demo.c starting from line 30 beforehand. Furthermore, you will have to exchange all "port" references with the corresponding port you're using for the Line Leader. I'm certainly not an expert on this and since I don't have the necessary hardware I can't help out out that much, but try the above first as I'm pretty sure that's what you're looking for. Quote
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