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[on:]

Hi people. i wanna know that if there is a means to update the position of a robot to another without using GPS?

[Reply #1 on:]

badri,

I assume that you are referring to two mobile robots.

How big is the area that they will be moving about (a room, an auditorium, or a large area outside)?

What level of accuracy do you need?

What will you do with the position data?

If you are only looking for a low level of accuracy, you could use a “dead reckoning system,” whereby both robots start at known positions, then determine their new positions by calculating the distance and direction traveled through encoder feedback. You would then need to transmit the new data through some kind of RF or IR link.

Assuming that the two robots are constrained to a relatively small area (room or auditorium) then a more complex method would be to use some kind of triangulating devices (two towers) that sensed and calculated the relative positions of the two robots. This could be done by either laser or ultrasound range finding (small room).

The second option using external range finding is more complex, more problematic and more expensive than either a dead reckoning or GPS based system.

[Reply #2 on:]

thank u sir.. as per ur advice i am going to try out dead reckoning:)

[Reply #3 on:]

Another possibility, if you have control over the space where the robots will be running (this wouldn't work for a general room or a house or something; more like a lab environment):

There is a technology out there, used by LeapFrog and other manufacturers, with a special pen and paper, that can tell where on a sheet of paper the pen is at, and what sheet of paper the pen is on. Each manufacturer of pens and paper is licensed a large "spatial area" of this special paper (many square miles in size, actually). The paper has small dots on it, that the sensor in the pen can read, and the dots are arranged in a grid manner so that the pattern of dots is unique and spatially (in 2 dimensions) distinct from other areas; so the pens knows where it has been, where it is at, and what it has wrote and where - and on what sheet of paper. It can even know when it is on someone else's paper.

So - if you could implement a similar system, and paint/draw/print your custom "grid" of points on the surface that the robots run on, then each could know independently where they are in the room, and then (if needed) update each other with their positions.