More Mule then Rover?

[Tommy_T]

Stobs, I'm thinking Wifi is not the answer for this project. yes it was easy to implement
giving me more time to work on weights,power and control issues the Mule's first winter.(I learned a lot)
But it is unreliable at distances greater then @300ft or non-line of sight of @200ft.
I gave the Mule the processing power to accomplish it's tasks, IMO it's time to use it.
Time to start thinking outside the box for ways to keep the Mule in it's box(my yard).

Tommy

[Stobs]

I really don't know much about communications, but what about working with cell phones? They seem to work in any weather - well, if you believe the commercials anyway :} and some models have USB connections. The family plan that I belong to lets us upgrade our lines at two year intervals, depending on when we started service/last upgraded; might be able to make a contact at one or more of the local phone outlets and see if you can put up a wanted notice for someone's old phone? That wouldn't work that well with my service plan, but if yours is high/unlimited minutes and reasonable data rates it might be worth looking into.

[Tommy_T]

but what about working with cell phones?

As is I have a USB 2G/3G aircard(for car's PC) with unlimited air time, but this august the mule
is going to my mom, she would say no thanks if it costs $60+ a month on top of the charging costs.
I'm also shy about connecting the Mule to the Net, all tests with Wifi have been with routers not
connected to the net.

I'm testing creative ways to use a webcam so the Mule can follow a programmed path.


Tommy

[Stobs]

...if it costs $60+ a month...

Exactly why it wouldn't work for me either, at least not with my current plan.

[Tommy_T]

Completed tests of friction drive Reel mowers on the Mule, and while it had it's advantages
it couldn't give repeatable results, too many things can stop the Reel from turning, which
does makes for a very safe(as mowers go) mowing deck, but requires human intervention
to remove object before it can continue. would work for gulf coarse greens, but not large
lawns with trees or bordering corn fields(like my test area). Also with six fixed wheels in
contact with the ground while mowing lots of energy is needed to maintain a straight cut
path.

Next testing electric motored conventional rotary mowers(I got one last fall)

Tommy

[Pabble]

I agree with Tommy, the reel mowers are great as long as you clear the yard of limbs and such before you start mowing.

I have been experimenting on a small scale with the use of GPS. I have had some success but so far the accuracy is not there. I may purchase a more accurate module later if budget permits.

Something I have been running around in my mindseye is using object recognition and have the mower place cones or other objects at the end of each run. The object would be tracked keeping the mower inline with the object. When the mower reaches the object, it picks the object up and places it in the path of the second run. This process would require 2 objects for each end of the yard area. I have used Keyence Cameras with object recognition at work and they work really well. Not sure how well it would work with such a busy environment and with changing perspective.

Anyways I am on hold until the flood waters of the mighty Mississippi have subsided. I have not had water problems yet and probably will not but just in case I have most of my hardware stored in safe keeping until then.

[Tommy_T]

I have been experimenting on a small scale with the use of GPS.

Pabble, I also have been testing a GPS(Phidgets), I can't use a digital compass to get
the Mule's bearing because of the EMF of the electric motors, both drive and 38" electric
mower deck, I hope to get that information from the GPS.

my mindseye is using object recognition and have the mower place cones or other objects at the end of each run.

Not a bad idea, but would try this first(seems simpler) http://www.petsbycsn.com/Loc8tor-LOC...R1001.html?cv=



I duct taped a 38" electric mowing deck together.

Tommy

[coppertubing]

I'm testing creative ways to use a webcam so the Mule can follow a programmed path.


Tommy

Tommy, take a look at Roborealm. It has the ability to process webcam video and use it to navigate a robot. There is a module available that will record the webcam video of a driven path and use it to drive the robot. The navigation module can also plot its own obstacle avoidance path.

BTW, I am also building a large rover based on a Jet 3 Ultra wheelchair and want to use it for lawn mowing. So I have been following your project with great interest. The mower I'm looking at is the Fiskars Momentum, which uses a flywheel to turn the blades, and is a push not pull reel mower.

[Tommy_T]

I have been experimenting on a small scale with the use of GPS.

Pabble, A good way to test a GPS device would be to record the GPS data(say every second)
then overlay that data on say a Google Earth image.

In the example below the light colored line is the GPS data, I used a joystick to run the Mule
around the mowing area recording the Lat,Lon data to a file. As shown below trees do skew
the GPS values, while open spaces does a very good.

take a look at Roborealm.

coppertubing, I have yet to check out any of the ROS packages, all examples I'v seen are small
indoors robots, hard to see a connection with the Mule.

BTW, I am also building a large rover based on a Jet 3 Ultra wheelchair

If your not going to use the P&G motor drive and would like to unload it, let me know.

Tommy

[Pabble]

Pabble, A good way to test a GPS device would be to record the GPS data(say every second)
then overlay that data on say a Google Earth image.

In the example below the light colored line is the GPS data, I used a joystick to run the Mule
around the mowing area recording the Lat,Lon data to a file. As shown below trees do skew
the GPS values, while open spaces does a very good.


Tommy

Very cool Tommy, I will have to experiment with that.

Were you driving the Mule by camera while gathering data? If so you seem to be getting a very good range and I would be very grateful to know what you are using for a transmitter/receiver. The best I can get by camera around buildings and such is roughly a couple of acres. I get a very good range in open field with no obstacles.
Mostly I enjoy mowing the yard on my riding mower but when it gets windy and dry with all the dust and pollen then my sinuses and eyes suffer. Thinking of modifying one of my motorcycle helmets to wear while mowing hehe
My Video receiver is hooked to a 32" LCD HDTV and I tend to get motion sickness if I drive by camera very long and mowing remotely gets very boring hence the search for autonomous operation.