Author Topic: Robot Follow a route  (Read 3919 times)

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Offline andreahmedTopic starter

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Robot Follow a route
« on: December 12, 2006, 06:29:49 PM »
Hi, i've seen that page
http://www.ikalogic.com/wfr.php
and i like it , but i dont know how one can make a robot that follow a predetermined route  ???? but i think he's using a wheel encoder , but it may happen that a wheel that strip on earth and let the encoder count uneeded pulses ...  there are alot of problems right ?
 ::) 

Offline Militoy

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Re: Robot Follow a route
« Reply #1 on: December 12, 2006, 07:37:35 PM »
I am not sure I understand your question, but if you are asking about wheels slipping on soft earth, resulting in odometer errors - it can be a problem. This isn’t usually too much of an issue in a “hall-bot” though, and with the proximity sensors, the robot should be OK. There are a number of published studies on dead-reckoning errors, and how to correct them. Unfortunately, most study robots use a combination of GPS and dead-reckoning, so their methods may not help. I enjoyed reading on the link website, the way the builder improvised and used LEDs for both his emitters and detectors. It reminds me of how in Junior High, we used to saw the “roof” off of scrounged TO-3 transistors, and use them for photo-detectors.

Offline andreahmedTopic starter

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Re: Robot Follow a route
« Reply #2 on: December 12, 2006, 08:08:19 PM »
yea , im impressed of how he desinged his proximety sensor ! :) he's egyptian like me ;)

i wanna know how to follow a route i cant wait really for the final article ^^

Offline Admin

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Re: Robot Follow a route
« Reply #3 on: December 13, 2006, 10:43:13 AM »
as militoy said, there will be a large build up of error over time. i strongly recommend against using encoders for pathfinding without other sensors to correct for error.

not sure if you saw this encoder tutorial yet . . .
http://www.societyofrobots.com/sensors_encoder.shtml

its one of my first tutorials, i really should rewrite it . . .

Offline ikalogic

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Re: Robot Follow a route
« Reply #4 on: May 28, 2007, 07:01:34 PM »
Hi, i've seen that page
http://www.ikalogic.com/wfr.php
and i like it , but i dont know how one can make a robot that follow a predetermined route  ???? but i think he's using a wheel encoder , but it may happen that a wheel that strip on earth and let the encoder count uneeded pulses ...  there are alot of problems right ?
 ::) 


hello eveybody, this is my first post here, i am the author of the article waypoint follower robot article,

just saying that the article is finished!

http://ikalogic.com/wfr.php

hope you find it interresiting.

Offline sdk32285

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Re: Robot Follow a route
« Reply #5 on: May 28, 2007, 08:11:15 PM »
If your only using Dead Reckoning and want to correct for error you would usually use a kalman filter (very complex, However if your good at programming you can sometimes find a similar one online that you can modify). Another approach is to have a "dummy" caster wheel with low resistance touching the ground. If you put your encoder on this wheel it can give you an estimate of actual distance traveled. Problems with this are numbers can get funny if you have a lot of turns/ curved paths.
Robots for Roboticists Blog - http://robotsforroboticists.com/

Offline twist_best

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Re: Robot Follow a route
« Reply #6 on: May 30, 2007, 09:27:07 AM »
Question!!! ??? I've seen ikalogic site n it use a photocoupler to read an shaft encoder,right?
how about the noise from light (for the photocoupler)?
isn't that can change photocoupler characteristic??
in my project,i use a mechanical encoder that usually used at opticall mouse..

Offline Admin

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Re: Robot Follow a route
« Reply #7 on: May 30, 2007, 08:23:09 PM »
twist_best, I dont quite understand your question . . .

Your software/hardware should account for any possible expect noise in your sensor - this goes for all sensors not just encoders. But usually it shouldnt be a problem, especially if you buy a prebuilt encoder.

 


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