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First personal project.

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Tommy:
Hello Forum!

I'm new to both this forum and to personal robotics. for the last 25 years I've worked as a
system integrator for the manufacturing industries and have worked on projects with industrial
robots, but this is a first try at this type of personal project.

I should also let you know that my grammar, spelling skills and artistic talents are very limited.
I also love it when I'm told it can't be done.

My Project: General Lawn care robot.

Project budget $2500.00

Because I still have to work I'm giving myself 1 year to complete the project.

Tasks is most perform
1) carry payload of 150lb (at least 2 bags of potting soil)
2) mow grass (both manually(remote control) and autonomously(with supervision)) 
3) clear snow for drive and walkways manually(remote control)
4) simple to control (even my 75yr old mother can use in her garden)


The main controller is going to be a net-book PC(or my dual core laptop in need be)
remote control operation will be Bluetooth(wireless keyboard) and WiFi.

Servo control is analog(0V to 5V).
Speed controller RobotQ Ax2550 - (Sabertooth 2x25(for testing) and Peripheral Attachments )
Transducers Phidgets 3/3/3, Phidgets 8/8/8, Phidgets high speed encoder cards(at least 2) ,at least to encoders.     
Analog output Labjack U3-LV

After searching this forum on similar project I'll use a used power wheelchair as a test bed(found on craigslist, picking up Saturday).

Feel free to correct me when you see I'm wrong.

Tommy




 

Conscripted:
Sounds like a useful contraption when finished. I have one question. Will two drive wheels and two casters give you the traction you are looking for to shovel snow or traverse a garden?

Conscripted

Tommy:

--- Quote ---Will two drive wheels and two casters give you the traction you are looking for to shovel snow or traverse a garden?
--- End quote ---

Conscripted
In my head I can see me having to make and install chains on the Drive wheels or
maybe Tracks, if I can get the test bed at the price quoted on graigslist and it well work
I should then have the budget to get tracks(if needed or usable (could cause damage to lawn or garden?)
A company call ariens makes a Track kit for snowblowers that could be retrofitted.

It seems there are lots of options when it comes to tires.
http://www.wheeleez.com/

Tommy

Tommy:
I got the test bed (came as advertised, and more..Sweet!)

While disassembling I got a look at the drive that came with it (Penny&Giles 50/70 Amp VSI speed control).
And I gotta say it is a sweet drive, and if theres a way of using it I could shave $500 off the budget.
The other sweet thing about that drive is it has built in safety features like battery level inductions, differential
analog monitoring ,analog voltage level monitoring and Motor current monitoring.(shorted or stalled motor can't take out a drive..sweet)

using the P&G drive would remove the need for a Microprocessor as a hart beat also saving $100.

But it has built in acceleration/Deceleration loops that would cause me issues while under autonomous control.  

First question: Has anyone ever tried to remove or change the Speed profiles on a Penny&Giles 50/70 Amp VSI speed control ?.

I goggled it and found references to a Speed profile programmer for Dealers, OEMs and Manufactures, but none for end users.


Tommy  

Soeren:
Hi,


--- Quote from: Tommy on August 29, 2010, 07:51:16 AM ---using the P&G drive would remove the need for a Microprocessor as a hart beat also saving $100.

--- End quote ---
A ┬Ácontroller is just a few bucks, but I don't see why one motor would need it while another wouldn't?



--- Quote from: Tommy on August 29, 2010, 07:51:16 AM ---But it has built in acceleration/Deceleration loops that would cause me issues while under autonomous control.  

--- End quote ---
Why would it?
Just use encoders on either the wheels or the motor shafts and count pulses, then you know how far each wheel traveled. With a bit of testing, you will probably find how much you need to modify a given distance at a given speed for complete travel.



--- Quote ---I should then have the budget to get tracks(if needed or usable (could cause damage to lawn or garden?)

--- End quote ---
Why would tracks damage the garden more than wheels (as long as you don't rotate too much in one place)?
Tracks will spread the weight over a larger area, so it will be lighter per square area of contact.

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