Dynamic interchange between wheel & track advice

davidlevin · Aug 17, 2009

First as full disclosure, I represent a start-up that is trying to determine if its technology has application in agriculture. We are not trying to sell anything since we have nothing to sell (technology does not exist). We know little on agriculture so we thought to come here and seek your advice, so here goes!

My company developed a technology that can dynamically interchange between a wheel and a track (video demonstration here for an articulated machine: Construction & Farming | Galileo Mobility). This is implemented in mobile robots (video here: Personal Robots | Galileo Mobility) and a stair climbing wheelchair. Our R&D indicates that this can indeed work reliably on a full scale farming tractor and have comparable price to a traditional tracked machine.

Before we invest our time and capital to invest in this, what we are struggling with is to determine exactly where and how (er if) this would be needed. Can you please help?

We found numerous researches comparing wheels and tracks talking about ground compaction, flotation, drawbar, speed, etc. But what we really want to understand is the actual application, the actual day to day use where this is needed. If possible, we would love an open discussion from people who use these machines day in and day out

radman1 · Aug 17, 2009

I don't have tracked ag tractor but friends of mine do. In my area the vast majority of new tractors have typical tire tractors. Tires are simple, cheaper to replace and work just fine in the vast majority of applications. Tracks give better traction in all conditions, smoother ride and less ground pressure because the track spreads out the weight. Tracks will last much longer compared to tractor with duals and MFWD. The down side to tracks are initial cost, replacement and maintenance. Tracks don't work well with row crops because they smash down too much crop when turning and require narrow tracts to fit down most rows. Most track owners also have regular tired tractors for row crops. Tracks are used mostly with high hp (250+) tractors with big, big machinery. Track owners also complain of the berms left on the ends when turning. Tracks can also get bound up with crop residue getting in the rollers. Less of a problem today, but early models were so bad that it could literally stop the track and tractor from moving. Incredible headache to remove the lodged material.
Tracks produce less compaction. Compaction results in poorer stands of crops, more run off of water, more wear on machinery etc. However, more and more farming is done with larger equipment and combined with no-till farming has greatly decreased the amount of compaction of soil. There are even starting to be some studies showing a detriment to loose soils.

Ideally, your design would best work if automatically raised back to normal tire mode with any significant turn of the tractor to stop the berming issue and wear on the rollers/track. Durability will be the other main issue. The front rollers on track tractors are fairly large. Your small wheels will have durability issues and crop residue issues. Your expandable track may also have issues with residue getting caught in the track when expanded. Your expanded track will be much more expensive than a fixed length track. Can your rollers take ditches, terraces etc when placed on a tractor weighing 20,000 lbs and then add additional fertilizer tanks of 5000-6000 lbs in the mid and front of the tractor? Can it handle rear 3 pt hitches than can lift an additional 18,000 lbs?

Your design should be able to handle field speeds up to 7-8 mph. Road speeds can be up to 30-35 mph but the rollers could be lifted for higher speeds.

I recommend you post on website AG Talk http://talk.newagtalk.com/forums/forum-view.asp?fid=2&DisplayType=flat&setCookie=1. All ag/farming and lots of guys with tracked machines. Get their input.

davidlevin · Aug 18, 2009

Thank you kindly for the detailed response - very much appreciated! Naturally, this raised several questions amongst our team:

You say track machines are always large machines. Would there be a need for smaller machines? Meaning if we can make this work, do you think there will be a need for smaller machines, (3000 or 4000 series JD machines)?
Are there tracked machines that are specifically sold for row crops? If not, do you know why?
Aside from turning at the end of lines, do you see other economic benefits to having both wheels and tracks on the same machine?
Is transportation distance to and from the field and issue? Our thought is to drive to the field on roads via wheels, and on the field via tracks

Regarding your questions, let me clarify:

Front boogies. Keep in mind you can open both boogies, only the rear or only the front. In the case that you mentioned you can open only the rear and thus the entire wheel would act as the front boogie.
Our tracks are not limited by width. Our wheel can be configured for narrow row crop work.
The wheel will expand and contract dynamically via user command, i.e. flip of a switch or pull of a lever. Can also easily make it automatic if needed
In track mode, the track will work like any conventional track with regards to pull, drawbar and lift. The boogies will be designed to meet the required loads you described. As such, would this technology allow you to now use smaller tractors for the same application rather than the 10 ton machines you mentioned?
Our cost should be similar or slightly above conventional track systems
Durability. We hope this would be one of the bigger benefits. We are assuming that since you'll use the track only when its absolutely needed, you'll be able to save the track life since you could be in wheel mode whenever possible. Do you think this assumption is correct?

As you recommended I will post on the Ag site. Thanks for the tip.

rambler · Aug 19, 2009

Two reasons to use tracks in ag:

Reduce compaction by spreading the load across more square inches.

Apply more traction to soft dirt to get the hp to the dirt.

Some specialty users that tend to pay big bucks for special machines come to mind. Sweet corn and pea harvestors need to run _when_ the crop is ripe, not when the weather cooperates. They will run through standing water in the field, if they can. Leaves terrible tracks, and often get stuck, with conventional lug tires.

So, they tried a tracked corn picker here for a year or two. They really liked it - for driving up and down the field. But it was terrible to manuver on the ends, to turn around and go back down the next set of rows.

I think they would be interested in a deal that allows them to turn a tight circle on the ends of the fields, but offers more floatation while going along the rows.

Regular farming, all the major companies are making rubber tracked tractors, JD and Catipiller/Agco run on 2 big tracks, Case runs on 4 tracks with an articulated tractor. I think farmers are pretty happy with these 250-500 hp machines, they go down the road well, they work in the field well. I don't see a big need for your technology on a 'regular' tractor. They need full power most all the time other tha going down the road; really no need to be switching between wheels & tracks.

Small tractors of less than 150 hp really don't need the expense of tracks for any kind of regular farming work? For _most_ of us.

The only low-hp machine that uses tracks are skid steer loaders - Bobcat brand, etc. A lot of companies make add-on track systems to these to improve floatation. If your system can take a lot of side-strain, perhaps it could fill a need on these?

There are 3rd party add-on track systems for combines as well. In wet miserable rainy conditions, a lot of combines will get converted to running on tracks. Perhaps your setup could work for this application as well, as a specialty deal. Again, wheels are better in good conditions for manuverablity, but in miserable wet times, tracks are better to just get through the field.

Grain carts (very large single-axle wagons that follow a combine through the field to get grain, can be about 1000 bu in size on a single axle!) are big enough to need tracks to handle the weight in soft ground. Perhaps there would be a use for your design on these as well? One likes to manuver them around, but again in wet conditions need more floatation....

I think I'd look to harvesting equipment for using a design like this. That is when we need to float through water in a bad year, or carry a lot of weight sometimes, but still like to stay very manuverable for normal conditions. I'd say the canning companies (pea, sweet corn areas of Minnesota, Illinois, & upper New York) would be willing to test a real machine quicker than anyone.

I do not know much about California - they have some unusual, specialized farming that needs real odd & difficult machines. Very few are built for these special operations, but they are willing to pay what is asked for if the machine can get the job done better. Us regular corn/ soybeans/ wheat farmers don't know much about that type of farming....

A lot of these machines are running 40,000 to 65,000 lbs when full, so the emphisis is on handling a lot of weight..... Or running well burried in sticky slippery mud.....

A few ideas?

--->Paul

mjncad · Aug 19, 2009

The dynamic drive wheel to track and back again concept is fascinating to say the least.

I can't speak to actual usage of tracked versus wheeled machines as I've only operated wheel machines with the exception of renting a mini excavator a couple of times. My big concern in any off-road environment is dirt and debris in the machinery, and I feel the mechanisms to provide the dynamic change in drive configuration are going to be susceptible to the junk encountered in the fields.

The stair climbing concept shown on your web site has lots of merit for wheelchairs and material handling machines.

If your engineers can overcome the severe conditions of off-road use, then the big tractor market may be the place for it. Most of us on TBN use CUT's (Compact Utility Tractors) and SCUT's (Sub-Compact Utility Tractors). I'm not sure that this technology can be made in sufficient quantity to bring the price point down low enough that CUT & SCUT owners could justify the extra cost.

Good luck with your venture!

Scooby074 · Aug 19, 2009

I agree with what the others have said so far. All great points and suggestions.

I dont see this being a sucess in the Compact market. The added complexity and cost just wouldnt pay off at the at this level. I could see a limited use in snow perhaps as a snowmobile trail groomer but the market would be small and is served by other products.

Perhaps vineyards could make use of the product on slopes? The independently adjusting bogies could be beneficial to leveling the tractor on steep grades especially if a auto-leveling system could be developed.
There are competetors in the small market already such as the 76Hp Kubota Power Krawler but of course it doesnt have your technology. Kubota Tractor Corporation - News Release

Skidsteers would be another market as mentioned.

Perhaps excavators? while steel tracks rule, there is a limited market for wheeled machines such as used by municipalities. They prefer wheels for reduced damage to the roadways and less time and cost to move and setup the machine. A track like yours would allow for the benefits of wheels, but give the benefits of tracks for off pavement use when needed. Example : http://www.cat.com/cda/layout?m=111785&x=7

Some concerns with your product in the heavy ag makret:

Your track appears to be elastic in nature. Can it handle the extreme stretch that large tractors could place on it?

Also id be concerned with keeping mud out of the track and its mechanism, which could prevent the retraction into "round" mode. When your track expands, it looks like there are voids in the side of the track, if so they will be packed with mud.

Heres a video of a stuck case quadratrack to illustrate the conditions a track system could see
http://www.youtube.com/watch?v=0I3HanCPMXg

Also there are products like the Soucy track which is removable allowing farmers to run wheels when convent.

I do see a future for your technology, the video with the security robot was both entertaining and enlightening. The section with the ladder climb was amazing! But im not sure about the future in agriculture due to the above mentioned issues.

Good luck on your endeavour.

MarkV · Aug 19, 2009

I had thought about the vineyard market also. They already make low profile tractors for that application to add stability on terraced side slopes. These tractors are not as large as the crop tractors in the 200hp range that presently use tracks.

MarkV

radman1 · Aug 20, 2009

davidlevin

I agree with most of the above points. Rambler hit most of them. Tracks are best for large hp tractors to get the traction in both dry and muddy conditions. Secondly, to reduce compaction. The smaller tractor market would have some uses but would be much more specialized use rather than general farm use.
Some farmers used tracked machines in row crops. Most companies will make a narrow track for row crops. Usually about 19-20" wide.

If your track system is similar in price and durability, then yes, there would definitely be a market. Use the tracks when needed, otherwise run them like a wheeled tire. I assume you have patents. Teaming up with a major ag company would be good. I could also see a big potential market as a replacement system for current wheeled tractors to be converted to tracks. That has really big potential and would allow you to go on your own as a company. Can your system be designed that way? I would guess it can be. This would work great by replacing the back wheels of tractors or drive wheels of combines. This could be valuable for both large, midsized and smaller tractor and would allow it to work with nearly any companies tractors. Call me up and let me in!
The wear on you system should be much less than a tracked system. Only convert to tracks when need. Many larger ag tractors have systems that monitor wheel slippage/spin relative to ground speed. The tractor has ground radar and determines % wheel slip. I could envision your system expanding and contracting automatically based on % slip and therefore leave the operator alone to manage the other duties.

davidlevin · Aug 20, 2009

Your feedback is fantastic, thank you!

You mentioned 2 main markets:
1. Vineyards & specialty tractors
2. Big Tractors

From a technology perspective vineyards would be the ideal application to start with here. The size, speed, weight of the machine would make it a natural jump. Does anyone here have direct experience with this? Do you know why they need specialized tractors? How many tractors or different types of tractors are needed per a size of land? What are their pain points, main issues?
Naturally, we'll do our own research here, dive deeper based on your in put.

Scooby074: The tracks appear elastic, but they are not. The track belt only folds and unfolds, it never stretches. The elasticity comes from an embedded spring. Instead of the embedded steel cables within the tracks we have other material that provide similar if not better properties. In track form, the machine will be like any rubber tracked machine. Debris and mud is absolutely the main technical issue. Our robots have been in military field test for nearly 2 years now and not once have we had an issue of closing the track (most of all to our surprise). Granted this is a far smaller application, but the concerns were the same. What we've found is that the combination of the turning of the track plus the vibration of the spring actually pushes debris out as the wheel is closing. Worst case scenario, if you do get jammed, you can always continue to work in track form. That said, there's much engineering work to do to verify that this works reliably.

Rambler: Took your comments on the sweet corn and pea harvestors. Did some research and found this ground compaction research by Prof. Godwin: http://www.tapg.net/pdf/2009_semina...eld_day_DickGodwin_Alleviating_Compaction.pdf
In itself this is useful research for us. Note the GPS log on the 2nd page. Imagine you're harvesting with the track, all the turns (quite a few there) and transport you do with the wheel. Looking at this log, can potentially save a lot of money. Am I way off here?

Radman1: I cannot tell you how encouraging your remarks are. As a small engineering firm to understand that the main gap between us and a potential need is technology is exactly where we want to be. Technology we know we can or we can't solve, but it something we can make the call on. Market need, we cannot.

This system is designed to be a bolt on kit. While you can potentially build a machine around it with new capabilities, we're nowhere near that. Our current designs are plug and play.

Creating an automatic system that can optimize traction based on slip feedback is something that (we think) would not be difficult to do. If the slip feedback is already there from the machine, creating an algorithm that can tell the system when to contract and expand is certainly doable. My question for you is how critical is this? If we can solve this problem, are we answering a real need? Or is this something you guys can easily deal with?It is our understanding that in heavy draft work this may be important.

No doubt to bring this to market we'll need to team with a large Ag OEM as you suggest. In fact, a few have shown some interest even at this very early stage of technology. We need to first prove we can do what we say we can before we build a product with them. For that we need to raise capital, and for that we need to show there's actual need out there. This is why I'm here. Thanks to you all, its beginning to take form.

radman1 · Aug 20, 2009

davidlevin said:
Creating an automatic system that can optimize traction based on slip feedback is something that (we think) would not be difficult to do. If the slip feedback is already there from the machine, creating an algorithm that can tell the system when to contract and expand is certainly doable. My question for you is how critical is this? If we can solve this problem, are we answering a real need? Or is this something you guys can easily deal with?It is our understanding that in heavy draft work this may be important.

.

The automatic system would have appeal but not critcal. Heavy draft work, muddy conditions, and soft soil would have its benefits. Often the operator doesn't know if there is significant slippage unless by a readout. On a wheeled tractor slippage over 9-12% is considered too much but often this may not be noticeable by the operator. A bolt on system maybe difficult to get automatic deployment of the track. However, at least the operator will have the readout to still tell the % of slippage even with your system bolted on.
I think the auto retraction/deployment of the tracks when turning is much more important. Most ag MFWD tractors will automatically turn off engagement of the front wheels when turning beyond a certain degree and turn back on when going straight. You may have to "tie" into the same tractor system for your tracks vs wheel configuration. You could also add an electronic switch on the front axle/tie rods and then tell your system when to retract and extend.