Location Tracking

Hi Robert,

Without local things to sense (like buried wires etc) I think it's not easy to do it repeatably with reliability, and that's of prime importance for your use-case I guess.

If you have the ability to mount a camera high up with visibility of the entire area (not at a shallow angle) then things could be easier, but would require something like a Pi.

With that and the camera attachment plugged in, you can use software called 'OpenCV' to recognize the lawnmower and its co-ordinates.  It is quite effective, and easier still if there is some special color or large pattern on the lawnmower.

Then some maths is needed to translate that into a real position and then translate that into instructions that would direct the lawnmower correctly. It's a lot of work to do though, it wouldn't be a quick solution.

You could also check out ROS (Robotic Operating System) - that may have suitable plugins or apps for camera feeds (e.g. a camera attached to your device) and image processing, but again this is a lot of work if you've never used it before. That's not to say you shouldn't attempt it - lots of useful skills can be learnt by doing this, even if the end goal is still far away, and you may then be in a better position to decide if you wish to continue that path, or not.

If you have the time and a Linux box (e.g. Pi) and some camera, it is quite straightforward to get going with OpenCV.

To do that, go to https://www.raspberrypi.org/magpi/  and in the search box (unintuitively not at the top of the page, but below the banner) type opencv to find articles on image recognition type topics which is what the camera method approximately needs - I have not read them, but they are designed for beginners. You'll probably also want to get a book on the subject from your library or Amazon etc.

If not via a visual system, radio is a bit tricky to localise, but light generally is not. I wonder whether you could rig up some criss-crossed high-power infrared beams or something like that. Detect obstruction by lawnmower to determine location. Or do a little more sophisticated like some of the laser-ranging devices and actually get a distance measurement as well? A bit hard in outdoor sunlight or inclement weather though.

- Gough

That is one route i did not think of but makes sense ive played with opencv a lil as i have a PI im looking to do something for a project for my engineering class that will impress my proffessor instead of these little retro game consoles my class mates are making i will definitely be looking into this thank you for your input

I thought of doing that with a lidar sensor but the amount of sensors needed and where to mount them wouldn't be practical or cost effecrive if it was for my own yard sure itnwould be fine but in real world use the cost would just be to crazy but thank you for your input all is appreciated

No problem, you're welcome! OpenCV is a great thing to experiment with, and along the way lots of interesting procedures and algorithms will get learnt, and you'll learn about data reduction, training image sets, etc. Plus you get to play with Linux and Python : )

I have a robot vacuum cleaner that does a great job of mapping a room. It has several forms of obstacle detection but seems to have a way of counting its steps (wheel revs) and keeping track of its direction by looking at the differential between left and right wheels. This is just a guess on my part but it is the only thing that seems to explain it ability to vacuum the room just as I would mow the yard, back and forth with a slight over lap.

John

Has you or anyone you know tried or succeeded in setting up a GPS base station set to a static location. This whay when it gets GPS readings it can correct for any errors in propigation delay and correct the rovers location basicly a home made dGPS giving much more accurate location readings?

I haven't, and there are special techniques that can do that (with accuracy to a metre or so) but they are not hobby-level techniques today from what little I know. An example use-case for those techniques is tracking people in stores, to see what aisle they are in. There are beacon techniques too that are far cheaper/easier, but that likely won't get you the resolution+accuracy you need either. I think optical techniques as Gough Lui mentions, or camera techniques, will get you the accuracy, but it is still not easy, maybe many months work full-time just to have a prototype, using these types of methods.

Well now that Yall have given me somethings to think about wish me luck!! I will come back and update as much as I possibly can as my first implementation will be just a small rover that I already have. Thank yall so very much please do stay in touch and anyother Ideas yall have or even come up with something new please dont be shy  as the members of this forum have been my greatest resource thanks again guys!!

One way to know position is simply measure 2 distances. For example put a stake at each of 2 corners of the property and measure the distance to each stake from the robot using any distance sensors. The third side of the triangle (between the stakes) is fixed and known so you know the position of the robot. The measurements can be as simple as string pots, but many other technologies can be used to measure the distance.

Another simple method is to use dead reckoning using a compass and wheel counting. This method probably also needs a perimeter detection system.