Best Steering / Frame / Tractor Combo -- for Robotic-Electric.

   / Best Steering / Frame / Tractor Combo -- for Robotic-Electric.
  • Thread Starter
#11  
Thanks. I tend to think of that style as something of a "tugger" -- like the various tractors move jets around an airport.

One key feature I am trying to get onto this is a cord -- so the battery can stay small, and pretty much just to be used to move itself, or may tow a "lite" something, about like that mover -- battery small, and still allow the thing some serious firepower when it gets to work with real power from the cord.
 
   / Best Steering / Frame / Tractor Combo -- for Robotic-Electric. #12  
PowerTrac PT425
Articulated loader
800# lift
1500# machine
All attachments on the FEL arms.
Tiller, post hole auger, planter auger, forks, trailer mover, mini-ho, trenchers, over 40 attachments.
Quick attach and FEL arms included in price.
Fits in the bed of a standard pickup with an attachment.
Someone already converted one to battery power.

There are threads about it here on TBN.
 
   / Best Steering / Frame / Tractor Combo -- for Robotic-Electric.
  • Thread Starter
#13  
PowerTrac PT425
Articulated loader
800# lift
1500# machine
All attachments on the FEL arms.
Tiller, post hole auger, planter auger, forks, trailer mover, mini-ho, trenchers, over 40 attachments.
Quick attach and FEL arms included in price.
Fits in the bed of a standard pickup with an attachment.
Someone already converted one to battery power.

There are threads about it here on TBN.
ahhh. That is what you have in your picture. But that makes sense as that is what is listed in your type. (duh, huh? ;) )

These do not exist as standard product Electric? (yet ;) )

and here is the retro? Electric Drive Motor Retrofit
 
   / Best Steering / Frame / Tractor Combo -- for Robotic-Electric. #14  
I would think zero turn would be the cheapest and easiest. And the lightest weight. Depending on how fancy you wanted to go a single axle with open diff and brakes on each side for turning would work for a prototype. I think that is how the Tamiya RC tanks used to work. Gearbox driving both rear wheels with the steering done by a brake on each side. May have been for scale realism but I haven't read the blurb for a while and never owned one.

Might be worth going to wet brakes to keep the wear under control on something bigger.

James
 
   / Best Steering / Frame / Tractor Combo -- for Robotic-Electric. #15  
Light weight might be beneficial for a lawn or field mower, but traction is a key attribute for a multi-purpose tractor.

Light weight is less efficient for ground engagement tasks.

Also wondering about the real life usability of being tied to an umbilical cord for power.

Compare the use of a traditional vacuum cleaner vs a free roaming Roomba style vacuum - dragging a cord over a carpet is exponentially easier than dragging a cord around a field, or even a golf course smooth lawn. Add one obstacle (a gate, a shrub or tree) to maneuver around and you're done.

An alternative is use of external add-on battery power packs.

Design attachable large battery packs for work activities. Large battery packs would also work to replace ballast for weight...(replace the ballast box with battery power).

Design them to be fast charging...and fast changing...simply back up to it, auto connect and go.

Provide limited battery power native on the tractor to maneuver without the external battery packs while hooking and unhooking to the large power packs.
 
   / Best Steering / Frame / Tractor Combo -- for Robotic-Electric.
  • Thread Starter
#16  
I would think zero turn would be the cheapest and easiest. And the lightest weight. Depending on how fancy you wanted to go a single axle with open diff and brakes on each side for turning would work for a prototype. I think that is how the Tamiya RC tanks used to work. Gearbox driving both rear wheels with the steering done by a brake on each side. May have been for scale realism but I haven't read the blurb for a while and never owned one.

Might be worth going to wet brakes to keep the wear under control on something bigger.

James
Thanks. Yes, Zero Turn is appealing on the low dollar aspect. And it suppose it handles well.

Since I am looking at doing full automation, and Zero Turn also controls and behaves well for automation.

With Full Electric drive the braking becomes sort of eas(ier) -- I can use re-generative braking where the motor to be slowed becomes a generator with a load, so it slows it down rapidly, (and can even stop and hold a load) before a mechanical brake even engages. When we do that for overhead cranes, the mechanical usually waits for the load to stop, and then locks onto the drive shaft of the motor. I use the re-gen braking on my Volt (Chevy car that has electric drive + a gasoline engine generator), and with over 100K miles, the mechanical disc brakes are not even worn.
 
   / Best Steering / Frame / Tractor Combo -- for Robotic-Electric.
  • Thread Starter
#17  
Light weight might be beneficial for a lawn or field mower, but traction is a key attribute for a multi-purpose tractor.

Light weight is less efficient for ground engagement tasks.

Also wondering about the real life usability of being tied to an umbilical cord for power.

Compare the use of a traditional vacuum cleaner vs a free roaming Roomba style vacuum - dragging a cord over a carpet is exponentially easier than dragging a cord around a field, or even a golf course smooth lawn. Add one obstacle (a gate, a shrub or tree) to maneuver around and you're done.

An alternative is use of external add-on battery power packs.

Design attachable large battery packs for work activities. Large battery packs would also work to replace ballast for weight...(replace the ballast box with battery power).

Design them to be fast charging...and fast changing...simply back up to it, auto connect and go.

Provide limited battery power native on the tractor to maneuver without the external battery packs while hooking and unhooking to the large power packs.
It is often a little too easy to pile weight on. For humans and mobile equipment. ;)

In this case, light weight is desirable for mobility between sites. Sort of funny but for things we need to add weight to -- like Solar PV, so it does not blow away -- we will sometimes use what are called "Ballast" systems -- concrete blocks, intentionally placed on a commercial ROOF, (sounds crazy, huh?) just to create dead weight. Looking at some designs to use water tanks for the same.

The Cord thing is mostly an interest of mine, but it becomes so much cheaper than a battery system, you could sort of consume or "burn through" some cords as an operating expense as it just part of the process.

The important part is what might be called "Cord Management" (for lack of a better term). Cord Management sort of being a planned way to deal with obstacles, not running over the cord, and minimized wear and damage to the cord. I have been running some small tests, and it seems like a do-able thing. This is sort of assuming that Grid Power is available at or near the work site, or can be easily added. And like you noted, if this is not so great, one can add batteries, later.

There is a discussion thread I started last week on that . . . here >>> Cord Management on Grid-Connected Electric Tractors and Mobile Equipment
 
   / Best Steering / Frame / Tractor Combo -- for Robotic-Electric.
  • Thread Starter
#18  
Here is the First Draft on Zero Turn.

Comments, Suggestions, OMGs all welcome.

Here are some notes ==

+ Steering Caster may be too much -- maybe more vertical?
+ Drawn with 20 inch tires. Frame is spaced to handle up to 24 inches.
+ Drawn with 1:5 Sprocket Ratio == motor nominal RPM is 1200 RPM.
+ Bigger tires may be better -- however, the larger the diameter, the more I have to gear down the sprockets.
+ Maybe the Drive Wheels should be "Front?" Lets it climb over things easier.
+ Over all dimensions are just what turned out. Trying to keep width under 3 feet to let it get through narrow paths, doorway, gates, etc. Could cut length down to 4 feet -- just trying to prevent it from flipping backwards with a pulling load.

Add on Edit -- Brakes. I am planning on using VFDs as load regeneration to stop either or both motors -- BUT -- I see I still need Emergency and Parking Brake(s). Looks like the left and right split axles may be the place to put those.

=============================

Zero Turn Side Section.jpg

=================================

Zero Turn Top View.jpg


==============================
Zero Turn Rear.jpg
 
Last edited:
   / Best Steering / Frame / Tractor Combo -- for Robotic-Electric.
  • Thread Starter
#19  
Next up . . . .

So that last one was the Zero Turn.

This one is the Articulated (Folding or Hinged) Frame.

Still has (2) Drive Motors -- but now is 4 Wheel Drive. That seems like quite a productive improvement.

Adds a Steering Linear Actuator -- sort of works like a two-way piston -- but that also means I can lose the Steering Casters.

Did two rough designs -- a sort of "long" one, based on a portion of the Zero Turn frame and motor mount, and a "short" design that comes closer to a model of a mini-front-end-loader.

As with the Zero Turn, I need to add Emergency and Parking Brakes, which can mount on the solid side-to-side drive axles -- which have more room to work than with Zero Turn split axles.

The center pivot and bearings, I have not done any real details on yet, and the same lack with the Steering Linear Actuator. I think some designs use (2) single action pistons (?). Dunno, will have to study the State of the Art and Best Practices a bit more.

Again, any comments, edits, suggest, or cautions are welcome.

===========================

ART LONG SIDE.jpg

============================

ART LONG PLAN.jpg


================================

ART SHORT SIDE.jpg


===============================

ART SHORT PLAN.jpg
 
   / Best Steering / Frame / Tractor Combo -- for Robotic-Electric. #20  
What about differentials on the articulated design?
 
 
Top