Best Navigation for Robotics — Parallax Forums
Best Navigation for Robotics
edited 2005-02-13 21:23
Hello, I'm a beginner in robotics and am planning to build my own autonomus robot. I am kinda hung up on what to choose for a navigation system. Any ideas?
edited 2005-02-13 16:37
what are your intentions.
What are you trying to navigate?
You need to ask the right questions before you get the right answers!!
whooo...that was deep! haha
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
edited 2005-02-13 17:13
By navigation do you mean get from point A to point B? You can use wheel encoders to see how far the robot has gone. GPS is another alterative, but alot more expensive and difficult to set up.
edited 2005-02-13 17:17
Two of best solutions for navigation are the ultrasonic range finder and the infrared detection system.
Here are a couple of links for more information:
edited 2005-02-13 18:50
Navigation is a very broad subject, it all depends on your requirements and budget. Here is an overview with some pros and cons, I make no claim of this list (or the pros and cons of each method) being exhaustive.
first off a few definitions:
relative postion (or location): measurement is defined in terms of the bot's starting position.
absolute position (or location): measurement is defined in global terms (compass direction, latitude, longitude are examples)
zero turn radius: bot turns without its center moving (one wheel turns at a speed exactly opposite to the other wheels speed.
ferrous object: any metal which can be magnetized.
ir, ultrasonic or contact sensor: just uses your avoidance system, cheap, provides no detail information in either relative or absolute terms.
encoders: counts wheel rotations or fractions thereof, fairly cheap, provides relative location information.
accelerometer: measures straight line movement and non-zero turn radius turns, moderate price, requires transformation from acceleration data to velocity data then to position information, can have trouble detecting slow movement.
compass: measures angular movement in absolute terms of both zero and non zero turn radius turns, moderate price, can be affected by proximity to ferrous objects.
gyroscope: measures angular movement in relative terms of both zero and non zero turn radius, some units can also provide straight line information, moderate price (units which provide straight line information are expensive).
GPS: measures absolute position, expensive, can be difficult to interface with, limited use indoors, accurate only on the order of meters.
As you can see no one method provides a perfect solution, for this reason many people will combine multiple methods to bridge gaps in information, but of course this will increase the cost. Encoders will give the most bang for the buck, but if you need absolute position, GPS is the only mentioned method that will provide all nessesary information in absolute terms.
edited 2005-02-13 18:56
You might what to check out the Robotics! with the Boe-Bot text-it should have the
information you need.
I think I know what I'm doing...
edited 2005-02-13 21:23
check out the Parallax "Articles by outside authors" bit, the article ""Where am I?: Minimizing Positional Error While Navigating and Mapping Using a Cooperative Robotics System" by Laura Wong is quite good.