Region coverage algorithm [URGENT]

[ichigohnvn]

Hi I'm new to robotics and currently working on a project relating to region coverage mobile robot.

The robot is supposed to cover all points in a specific terrain (unexplored, i.e. the robot must explore the region itself). This kind of robot can be applied for vacuum cleaning robot, and things like that.

Anyone has gone thru this kind of project can give me a hand? I need info. about the algorithm and relevant sensors needed.

Thank you very much.

[addy]

hi,
be a little more specific about the terrain on which u wanna ur robo to naviate ...... because alot of things will depend on that.
if the terrain is big and unknown... and u don want to collide with obstacles.... u ll have to go for sonars and do grid mapping of the entire enviroment and then proceed in the desired path as per ur algo...
so be more specific about the enviroment,....

[ichigohnvn]

Hi as you said the terrain is quite large compared to the robot and also an unknown region. The robot must cover all area by ifself.

I think I can use IR sensors instead, cant I? and could you tell my more about grid mappings and more specific algo. or where I can get that.

Thank you for your help

[addy]

hi there,

see ir's never gives satisfactory performance on many instances.....
it largely depends n reflectivity,smoothness, color of the surface of the object infront....
if the object is carbon black,,, u r dead.
but sonars r faithful...
by grid mapping i meant tat u can keep on scanning the entire surrounding around u, and then map the entire enviroment{in which area there r obstacles and where there's a free area to move} and then decide ur course of action.
but simple navigation is not gr8 idea....
think of some idea or some job which ur robo must perform in this course...
it can be anything, for a start up say, u can fix the coordinates of the ending point and the robo must reach there navigating thro obstacles.tat ll be a gud one ...

so first decide firmly on sonars or ir's????

[ichigohnvn]

oh yeah in fact my project is to build a robot capable of scanning through every area within an unknown region. It is like to build a vacuum cleaner or lawn mower, things need to pass through every area in the enviroment to finish its job. This is a region covering robot.

I think I'll use a IR sensor anyway, partially bcoz of my limited funding. So I would appreciate if you can explain more about this, things like mapping (how the robot does it) and how to design a proper sensor system for this specific job.

Thank you my friend.

[addy]

ok....
its pretty interesting problem{ to explore every point}
isnt tat simple....
u will also need feedback of the position to know where u r.
if u can use steppers, and contruct a gud drive system, then ur this tension might be reduced....
or else u ll have to go for optocouplers or wheel encoders for speed feedback.
anywayz begin with making a simple ir module for obstacle detection using tsop.....
get it done first, then proceed into other things....
do the project in a modular way.
gud luck.

[ichigohnvn]

hmm what do you mean by a feedback of the position? What is this and how to construct one?

[docel]

hI,
You need a 360degree Rotational Scanning Array.
Consider your horizon as 360 degrees. Divide area into 16 0r 32 quadrants. Scan each quadrant sequentially and memory map the results.
This is Positional Feedback.
Sorry, this is as simple as i can make it right now! :wink:

[addy]

ya, as docel sugested.... divide the 360' into small sectors....
mount ur sensors on a stepper motor and give a gud sweep...
u will get to know about all stuffs that r there in ur robo's surrounding....
now process it in ur algo for suitable decision making..

[devpriya]

Mount four IR sensors( the TSOP combination) on four stepper motors on the corners of the robot. Now grid mapping exactly means dividing the total area into a grid like a graph paper. You can have the points as the corners in the grid, now just move on grid lines and keep marking the points as visited.

I have suggested four motors so as you can map the area quickly, because doing it with one will take more time.