# Semi-Autonomy



## Vol (Jul 5, 2009)

A more realistic solution for farming. From Farm Equipment..... a dealer publication. A insightful read.

Regards, Mike

https://www.farm-equipment.com/articles/13907-semi-autonomy-a-more-realistic-solution-for-farming


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## luke strawwalker (Jul 31, 2014)

Yeah, I've thought for a long time that electrification of the power train and power transfer (PTO) functions of a tractor was an excellent idea. It's not by mistake that the railroad motive power went to diesel/electric powertrains DECADES ago...

As the article points out, the energy requirements necessary to do the hard work of pulling a disk, chisel, or plow, dragging heavy planters or sprayers through soft soil, or cutting and threshing grain makes PURE electric (battery powered) systems impractical, at least in the short term. The article clearly points out that the batteries required would be $350,000 and weigh more than the tractor itself in the current price point and technology state of the art actually being produced and commercially available. Therefore, a hybrid type system is necessary, something that can convert the energy density of diesel (or other oil-based fuels, either fossil or renewable) to electrical energy in sufficient quantities and a fast enough rate to power not only the prime mover (the tractor) but power linear actuators for lift/drop and electric motors driving the implements themselves... Sorta like the old "Electrall" but for the 21st century! Self-contained electric over hydraulic actuators are the state of the art in the aircraft industry, both military and civilian, due to their easy integration with "fly-by-wire" technology and the elimination of long, expensive, and vulnerable to damage runs of complex traditional hydraulic systems using centralized pumps and control systems and remote cylinders as actuators. Putting small "on demand" pumps with integrated reservoirs and self-contained valves and plumbing on the actuator itself is the most efficient and lightest weight way to construct a device to do the given job (if not necessarily the cheapest) which is why they're becoming more and more standard as time progresses. Plus, they can easily be controlled directly by computer using inputs to the computer from electromechanical controls feeding inputs directly the actuators through small lightweight and highly efficient wiring bundles rather than long runs of hydraulic lines and hoses.

Similarly, diesel engines (either of more traditional reciprocating piston design or more advanced turbine design) can produce the prodigious amounts of electrical power necessary not only to power high speed, high torque drive motors operating through the necessary final drives to propel the machine, but can also supply power via 'big dumb cables' to power remote motors directly on implements, things that are powered via PTO's today, through complex gearboxes, chain, belt, gear, etc drives... and do it more efficiently as well. Not only do you eliminate gear losses and most of the frictional losses (heat losses) through gear transmissions and hydraulic systems, but you eliminate things like power transfer through various angles (PTO shafts) since the connection is a simple "power cable" between the tractor and implement and a "wiring harness" that controls the various implement functions either through direct controls within the tractor itself (much as planter monitors and fold/unfold transport hydraulic control boxes work today, or modern hay balers with their electronic monitors and electronic controls on the baler itself). Engines can be designed to operate SPECIFICALLY at a predetermined set of "most efficient" modes (speeds/loads) to produce the electricity necessary on the least amount of fuel-- engines that run a single speed at highest designed efficiency also produce less emissions and last longer than engines designed to operate across a wide load of engine speeds and loads. The electric motors powering the final drives and implements themselves can easily be controlled electronically to vary speeds or handle varying loads as field conditions dictate, while not overly affecting the engine operation at all. Couple this with battery technology able to absorb excess power during light load conditions and provide a "burst" of additional energy as required when the going gets tough and you can really start to optimize the design of the prime mover (tractor or engine generating the electricity).

Throw in lower parts counts (by eliminating hydraulic and gear transmissions, PTO systems, hydraulic systems for operating transmissions, lifting and lowering equipment, or operating equipment like fans on vacuum/air planters, etc) and you could see some real savings, and less weight of the machines themselves, with lower power demands and power losses. SImplified drive trains are always a better idea. Plus, in some cases, regenerative braking (especially on hybrid systems with a battery that could "absorb" and store excess electricity from regenerative braking) could provide energy savings and raise efficiency.

As for the "fully autonomous" ideas of self-operating machinery, I don't think that's particularly realistic for farming for quite some time. Even relatively "simple operations" like disking or chiseling present problems that can keep even skilled and attentive operators on their toes... a rock that busts a disk axle bolt and starts scattering parts like disk blades and scrapers across a field, or even gets picked up and wedged in between blades and locks up a gang so it starts dragging up a huge mound of dirt and stalks... or a bearing that goes out in a gang and starts eating into the races and standard... These sorts of things can pop up and are totally unpredictable. In addition, there's no detector as efficient or simple as the "mark one eyeball" for detecting such malfunctions or problems, no code as efficient or quick at determining the course of action to minimize damage or correct it as the human brain... (when unoccupied by cell phones or other distractions and actually paying attention to the job at hand). Start looking at more "complex" jobs that require frequent refills or monitoring of the job at hand, like fertilizing, spraying, or planting, and suddenly there's a LOT more to go wrong, and a lot more that requires HUMAN INTERVENTION to actually correct or refill. Sure, automatic hitches and automatic couplings between wagons, sprayers, fertilizer tanks, etc. have been demonstrated and in some cases are commercially available... BUT they're neither simple nor cheap. Nor is the amount of monitoring required to determine if even something as simple as a disk is operating correctly "as set" or has suffered some sort of failure and needs attention BEFORE the tractor completes disking a 200 acre field and "parks itself" with half of a disk gang scattered across that field due to a broken axle or failure that the tractor's operating system didn't detect and stop before the problem got a LOT worse...

And, in such cases, if the farmer has to sit in the pickup on the turning row to babysit the "automated" machine, or pay "Pedro" to do it, even if they are both covering "multiple machines in multiple fields", that's still not much savings, compared to the costs of equipping the machines for "autonomous" operations. IOW, until we invent something along the lines of R2D2, an automated droid capable of keeping the machine filled, adjusted, and in the field operating correctly, we're not going to see "TRUE fully-autonomous operations".

Of course, electrification and equipping implements with sensors and such is the first step in moving in the direction of "fully autonomous operations".

Later! OL J R


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## rjmoses (Apr 4, 2010)

I agree with the idea of cutting costs, but I'm not sure electric is the way to go just yet. But it will be when cheap electric production, like fusion, is available. (Solar and wind are not cost effective--and probably never will be.)

"My point is that we need to stay focused on the problem: cutting costs out wherever possible and focusing on the largest cost line items. The thoughtful, practical application of new technology to farming operations has the potential to cut many costs by 50% or more. But to get there we need a dramatic re-thinking of our methods and tools."

The bigger issue is supply and demand. Our supply must be exceeding demand because prices are driven down. But one has to wonder--With world population and hunger rates, why isn't there more demand?

Ralph

Too early to be thinking this deep.


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## 2ndWindfarm (Nov 11, 2014)

I've always wondered why diesel/electric "hybrid" tractors were never adopted in the agricultural sector. Nearly 40 years ago, I worked on a project to clear several thousand acres of timber using LeTourneau diesel/electric machines.

40,000 lbs. with a Detroit 8-71 driving a DC generator that powered 125hp electric motors in each wheel. Incredibly simple and amazing power!

After reading a recent posting (with-pictures) from the owner of a $285,00 IVT tractor that blew up the $36,000 transmission, it left me thinking about that LeTourneau crusher and how much cheaper it was and how it would have drug that IVT machine backwards across the field!


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## clowers (Feb 11, 2011)

2ndWindfarm said:


> I've always wondered why diesel/electric "hybrid" tractors were never adopted in the agricultural sector. Nearly 40 years ago, I worked on a project to clear several thousand acres of timber using LeTourneau diesel/electric machines.
> 
> 40,000 lbs. with a Detroit 8-71 driving a DC generator that powered 125hp electric motors in each wheel. Incredibly simple and amazing power!
> 
> After reading a recent posting (with-pictures) from the owner of a $285,00 IVT tractor that blew up the $36,000 transmission, it left me thinking about that LeTourneau crusher and how much cheaper it was and how it would have drug that IVT machine backwards across the field!


LeTourneau University and factory is in the next town over, Longview, Texas.


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## somedevildawg (Jun 20, 2011)

2ndWindfarm said:


> I've always wondered why diesel/electric "hybrid" tractors were never adopted in the agricultural sector. Nearly 40 years ago, I worked on a project to clear several thousand acres of timber using LeTourneau diesel/electric machines.
> 40,000 lbs. with a Detroit 8-71 driving a DC generator that powered 125hp electric motors in each wheel. Incredibly simple and amazing power!
> After reading a recent posting (with-pictures) from the owner of a $285,00 IVT tractor that blew up the $36,000 transmission, it left me thinking about that LeTourneau crusher and how much cheaper it was and how it would have drug that IVT machine backwards across the field!


You answered your own question....40k pounds is gonna be a problem in Ag land


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## luke strawwalker (Jul 31, 2014)

somedevildawg said:


> You answered your own question....40k pounds is gonna be a problem in Ag land


Fully loaded combines already meet or exceed that for weight... Heck they're not a lot less than that empty nowdays... My BIL's 9600 Deere from the late 90's/early 2000's is 26,000 lbs dry (without the head IIRC) and his son in law's S600 Deere rotary is about 10,000 lbs heavier. Throw on 250-300 bushels of grain in the tank, and it adds up fast... More if they've got the tall/wide tank extensions on them (and most do).

Besides that, I think he mentioned something about it being a brush crusher-- in which case, those things are weighted up out the gazoo in order to be able to roll down brush and small trees, and put enough weight on the blades to cut through them and chop them up into pieces... so that explains the weight.

No real reason why a diesel/electric power system has to be any heavier than a similar diesel/mechanical/hydraulic type transmission and setup. IN all likelihood, a diesel electric would be lighter and would probably benefit from "weighting it up" to get the best mass distribution and traction...

Later! OL J R


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## luke strawwalker (Jul 31, 2014)

rjmoses said:


> I agree with the idea of cutting costs, but I'm not sure electric is the way to go just yet. But it will be when cheap electric production, like fusion, is available. (Solar and wind are not cost effective--and probably never will be.)
> 
> "My point is that we need to stay focused on the problem: cutting costs out wherever possible and focusing on the largest cost line items. The thoughtful, practical application of new technology to farming operations has the potential to cut many costs by 50% or more. But to get there we need a dramatic re-thinking of our methods and tools."
> 
> ...


If you're talking PURE electric, like that "new toy" Deere recently unveiled in France or wherever, then I TOTALLY agree. The "power density" and expense per unit of power (watts, horsepower/time, whatever) of battery systems just isn't enough for really hard working machines like farm tractors. Compare the rolling resistance of a Prius to a farm tractor with a plow, disk, or chisel sunk into the ground, or even dragging a planter or drill or sprayer through soft ground... there's just no comparison, unless your Prius is dragging a huge boat anchor behind it... LOL

Even the "best" pure electric (battery powered) vehicles cannot hold a candle to a hybrid or straight gas or diesel vehicle in terms of range... Even with batteries weighing more than a reciprocating engine and transmission in a "regular" vehicle of similar size. The energy density of liquid fuels is just SO much higher than the amount of electrical energy that can be stored in a battery (at least state of the art "typical" batteries-- there are some really exotic battery chemistries that can store enormous amounts of power, but they're either ridiculously expensive, EXTREMELY toxic or hazardous to handle and operate, or both... Or, have other drawbacks like limited lifetimes or highly hazardous waste to deal with when their service life is complete... or else they're just "experimental" and not really suitable for mass production and use.

It's like CNG, compressed natural gas. It has its place, like for powering city buses or delivery trucks making short runs and idling and never being too far from the base of operations where they can be readily refueled, which means that their limited range isn't so much of a liability. BUT, it's really unsuitable for over-the-road trucks that need to run hundreds of miles before refueling, hauling MUCH heavier loads at higher speeds (and therefore using more fuel, ie lower fuel economy) and need to fuel up QUICKLY and get back on the road, rather than sitting around waiting for the high pressure cylinders of CNG to be repressurized. Same thing with pure electrics-- that new Deere all-electric tractor that someone posted a story about on here required IIRC about 6 hours of recharge after about 3-4 hours of work... That is a LOT of downtime compared to a diesel tractor of equivalent horsepower that could run all day on a tank of fuel and take maybe 15 minutes to refuel and go back to work. Plus, if the electric "runs out of gas" in the field, it'll have to be TOWED back to the charging station-- hard to get electrons in a gas can... LOL

SO, for these reasons, among others like electrical grid capacity, losses in efficiency from energy transformation, etc. I think that liquid fuels will be around for a LONG time to come. Maybe someday when we have "Mr. Fusion" (like the Back to the Future movie DeLorean) we can go to pure electric power... or if we have some "miracle battery" technology that is discovered that maybe triples or more the current energy storage density of current battery technology. It'll require some SERIOUS upgrades to the power grid to handle the extra transmission of power if it's adopted for widespread use, as well... I've mentioned that before too. (While the greenies all scream like idiots for everybody to adopt all-electric cars, they don't think about the fact that if their car burns say 5 gallons of gasoline a day, their electric car will require a *broadly similar* amount of electrical power to do the same work-- electric power that now MUST COME FROM THE POWER PLANT AND THROUGH THE ELECTRICAL GRID to their electric car charger-- and the grid is already basically "maxed out"... Now imagine entire "neighborhoods" of McMansions all drawing extra power all night trying to charge up their electric cars for tomorrow's commute and after work chores/activities... Now imagine how much extra electrical capacity would have to be wired out to your farm to deliver the power necessary to run just one big 4WD articulated tractor or combine per day... my BIL's big 4WD burns 100 gallons a day, and the combine isn't far behind... that's a LOT of electricity!!! (And that's assuming a 100% conversion rate of power coming in from the power line into stored power in the battery, which is NEVER 100%... which means even MORE is required!)

It's the same reason why the railroads have stuck with good old diesel-electric technology for the last 60 years or so. Pure electric works okay where you can run catenary lines all over the place or a third rail to pull power from, but it's impractical for truly long-distance heavy-haul trains. For "lightweight" commuter/passenger trains operating in cities or in inter-city service, though, it works well. When you have to haul 100,000 tons of cars and cargo across states or a continent, however, the diesel-electric is FAR superior-- which is why diesel-electrics are still being built. Diesel locomotives can be RAPIDLY refilled, even with tanks holding thousands of gallons of diesel fuel, in short times, and have enough fuel to go several hundred of miles hauling all that weight. Tractors, farm equipment, and construction equipment have similar needs for high power density from the power (fuel) supply. Waiting for 6 hours or more for the batteries to recharge just won't cut it.

Plus, how many times can you refuel a diesel tank before it's "worn out"?? How much does a diesel tank (and diesel engine to use it to produce power) cost compared to a gigantic battery pack necessary to operate a tractor, like that new Deere... IIRC from the story that was posted they said the cost to replace the battery pack when its service life ended after about 25,000 charges (IIRC???) was about $125,000... that's a LOT of money for a "fuel tank". The same equivalent energy in diesel fuel could go through a diesel tank essentially forever... and when the engine that actually converts the diesel into usable work (or electric power for the electric drive motors via alternator) goes it won't cost $125,000 to rebuild or replace, unlike the electric batteries on the pure electric tractor.

Later! OL J R


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## kurt1981 (Apr 18, 2017)

electric will never work for tractors>I can see a huge govt program to prop up electric ag., quit subsidizing agriculture so the market can figure out true price and avoid the bubbles created and popped on a yearly basis we are no longer the breadbasket of the world so be careful.


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