General Misc > Misc

First personal project.

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z.s.tar.gz:
If you want maximum performance you have to cover everything with spikes, not just the tires.

Soeren:
Hi,


--- Quote from: Tommy on September 29, 2010, 04:38:56 AM ---While I can see the logic of the above line, there must be some variable overlooked. Because it seems like the new
tires draw @30% more current then the old tires, in my head I see that caused by greater friction between the
ground and tire, which may also be the reason it makes the Mule more sable on uneven surfaces(which is a good thing).

--- End quote ---
It was a generalization. You also get better grip in snow and ice if you let out some air on your car tires and the tire pattern can have a lot to say.



--- Quote from: Tommy on September 29, 2010, 04:38:56 AM ---I don't have drive current feedback my only justification for the 30% value is by testing with different
motor drive power input fuses, like install a 10Amp fuse then perform a task that would make the fuse fail then
increase the fuse value until the task is performed.(gone through 3 boxes so far at @3.00 each box, seems I
should install feedback soon).

--- End quote ---
+1 on that.
or at least a variable resettable fuse or current limiter.



--- Quote from: Tommy on September 29, 2010, 04:38:56 AM ---My next effort is to replace the 2 pole drive motors with 4 pole, in hopes of getting better low speed torque
in hopes of keeping the tire from slipping. it also gives me the opportunity to open up the gearboxes and
remove the lost motion before they are installed.

--- End quote ---
"Remove the lost motion"??
If it's lost, how do you remove it?

Why not gear down for less speed.



--- Quote from: Tommy on September 29, 2010, 04:38:56 AM ---Soeren, if I installed something like the picture below, my mom would start to cry just looking at it.
and I wouldn't get too close either, these big testbeds can be a handful.

--- End quote ---
Yeah, I totally get her, I cry too, whenever I remember that there is never gonna be another Mad Max movie - hey, why not kill two birds with one stone... ;D

Tommy:

--- Quote ---It was a generalization. You also get better grip in snow and ice if you let out some air on your car tires and the tire pattern can have a lot to say.

--- End quote ---
Soeren
Fact is I'm not all too concerned with the tire slipping issue, because my mom's lawn is not as bad as mine, and
I have feedback that keeps the mule on course even if a tire slips.

--- Quote ---"Remove the lost motion"??
If it's lost, how do you remove it?
--- End quote ---
Each of the four motor/Gearbox that I have(each about six years old) have some Backlash in the gears which
equals about a deg of lost motion between the Mule(Feedback) and the ground(Wheels). this is something that I need to
address one way or the other, The Mule's Q axis has .006deg resolution but I can't use it as is. I currently reduce
the gain of the directional loop to keep it from becoming unstable(oscillating).

--- Quote ---Why not gear down for less speed.
--- End quote ---
Very good idea, if I didn't have the larger four polled motors already which I think would be much easier to install
then try to gear them down, but it may turn out I'll have no chose but to gear down the gearbox.



--- Quote ---hey, why not kill two birds with one stone...
--- End quote ---
Funny you should say that, I was just thinking how to best use the linear actuator I have(gear motor/Ball screw type).
Now it's used to raise and low the rear fixed wheel, but with the wider tires I installed that is no longer needed. I could
use it for directional control of a third wheel(replace the rear casters with a single steerable fixed wheel) , or use it as
a kickstand for changing tires etc../get unstuck in the snow device.

Picture below is a example, if something like that was mounted under the Mule(forward of the front drive wheels)
in a way that when operated would lower the arm and lift the front drive wheels off the ground. If it was operated
longer it would push the Mule backwards some amount, at it's max travel the joint in the middle of the lift arm
would pivot letting the drive wheels back on the ground and also letting the arm return to it's default position
without returning the Mule to it's stuck position. the spring would keep the working end of the lifting arm out
of the way when it's in it's default(up) position.

I could see a device like below with two lifting arms one foot apart.


Tommy



Tommy:
Some dinking around.

Got the bigger four poled motor gearboxes tightened up(removed 90% of lost motion), but not all that
happy with the way I ended up doing it(drilled and pinned the main output shaft). I also got the motors
installed on the mule, which turned out oK but I'm also unhappy with the way it ended up being done,
(one wheel hub would not come off, so I toke it to an auto repair shop, they heated it until red hot...ouch!
but still could not remove it, I bough a 7ton wheel puller($36us at Tracker Supply) and used 4ft lever and got it off).

While I was at the local hardware store the first thing I spotted was them removing lawnmowers and weedwackers
and putting snowblowers and shovels in their place, which got me thinking about snow removal.

Without having any snow removal by plow experience I figure I should make my own snow plow for the Mule.
that way I could make changes cheaper and faster.

kinda like reinventing the wheel I would think, but it should be fun.

picture below is the starting the first ideas I had(all the parts I had laying around).


Tommy
 



 

Gertlex:
Looks goood.  I applaud your work, and laugh at the naysayers.

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