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Perimeter: object exclusion

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romualdas

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Hi,

Another question on perimeter wire layout itself.
I have excluded children playground area similar to the the figure 2 as shown in Wiki http://wiki.ardumower.de/index.php?title=Datei:Perimeter_excluding_objects.png The problem I have is that if mower hits the perimeter wire around playground (tree) first, then there will be problems:
- either it will turning infinitely around escape area "corner"
- or it will start turning, hit the playground and get stuck outsite the perimeter

Technically, I could do `Figure 1` style exclusion, but in that case robot would always go around playground, which would add quite few meters to track before getting home.

Any experience, suggestions or ideas how to properly implement exclusions so that robot would ignore detour while tracking, but at the same time escape if it hits the excluded area first?

Thanks,
Romualdas
 
Hi Tom
With raindancer maybe you can use the fast return to escape from island.
But it's better to see with Roland and into raindancer firmware topic.
By
 
Hey,

You definitely have to create an "escape area", which is the straight line from circle (marked with yellow), which forms this sharp edge on the bottom.
In my case, it worked to some extent, but not 100%.
In the end of the day - I have removed wired perimeter and built a physical fence (environment and design allowed). It works 100% all the time :cheer:

If making the changes to the environment is not possible, I'd go with `Figure 1` approach (was considering this option too).

Cheers,
Romualdas
P.S. I've seen in the forums some code updates regarding Island detection, but didn't investigated it further ...
Attachment: https://forum.ardumower.de/data/media/kunena/attachments/4472/Escape.PNG/
 
Zuletzt bearbeitet von einem Moderator:
Thanks guys, I'll have to give that a go!

I'm trying to figure out how the commercial mowers achieve this. In the Bosch Indego manual it says to keep the perimeter wires as close together as possible so the mower ignores the signal. It also says to lay the wire clockwise around an object. Maybe they rely on mapping the outer perimeter and can recognise an island?
 
Hi.

Simply check the odometry or imu (more than 720 degres after tracking start mean that you are into island).
But need to add the code into azurit and raindancer :huh:

By
 
Ah yes, that’s a great idea! I’ve played a little with the raindancer firmware so I’ll see if I can get something working ;)
 
I think we need the roland help to do that.
But first i want to test to see if it's possible to add a marotronics GY87 imu to the second i2c port on the pcb 1.3 (it's not possible on the normal port because the i2c adress is the same as the RTC).
But need to find time !!!!
 
Last time I checked, the code behind the island escape was to turn hard right after some time if the mower is making more left turns in total and leave the area this way.
This may or may not work. If the exclusion area is not round, but has something like `U` (my case) or `H` shape, then the right turn "inside" the shape may result in mower hitting the other part of the exclusion and continuing around the exclusion zone.
Same story goes if there are multiple exclusion zones nearby each other.
Eventually (probably) it would leave the area and hit the perimeter, but that may take some time.

Additional note: exclusion zones around small trees (if you want to protect them) have to be large enough.
If mower hits exclusion zone and turns 180 degrees, almost the entire mower length ends up inside the perimeter.
And if Ultrasonic sensors are used (personally, I'd not use them if bumper is available) then, if triggered after the turn, those can "scare" the mower even more deeper into exclusion zone.
That way, the exclusion zone has to be pretty large to protect the small trees.

So in the end I opted for simple but effective approach, built physical barriers in those few places, where it was needed.

P.S.
I had issues setting up RTC/IMU (tests show that faulty RTC is probably cause in my case) and there are quite a few discussions about the problems with IMU/RTC.
Odometry on the other hand, maybe not so precise, but works, so might be worth trying to use it with escape algorithm.
 
Here's the discussion to use odometry to detect island:
https://www.ardumower.de/index.php/en/forum/software-control/1458-stuck-on-an-island#13944
 
Hi
built physical barriers in those few places
Zum Vergrößern anklicken....
YES it's the best solution for small area exclusion.
It's also easy to put a timeout on the tracking .
You can use sonar with odometry to never hit the barriers(the bumper is here only as safety in case the sonar not work) https://youtu.be/zjQJ1htO5H8 The last and best solution to escape from island (not working actually) is to use RFID tag on the perimeter wire to localise the mower when tracking and help it to return very fast on the station.(Each tag have is own number so the mower leave the wire with the best direction to reach the station)
Actual test with 4 differents model show a very low read distance (less than 5 cm).
Maybe a real mower test for this winter ?
By.
 
Hi ich werde mich diesen Winter auch mit dem Thema beschäftigen, allerdings werde ich es mit Hitag oder Legic probieren mifare hat da einen zu geringen Leseabstand.
LG, der Olli
 
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