design options, and factors which impinge upon them

This is the second post in a series, which began with what operations should a ‘cultibot’ be able to perform?.

If you've read the masthead for this blog, you'll know that it is about how robotics can assist with the application of horticultural methods on an agricultural scale, so, even though I've been talking about gardening, the real goal is to apply gardening methods (or at least the attentive attitude of a careful gardener) over the entire landscape, ‘from sea to shining sea’, wherever land is managed as opposed to being left entirely wild. That's a tall order, of course, and no single system could conceivably cope with the vast range of conditions implied.

So, to simplify matters somewhat, I'll confine myself to consideration of land primarily engaged in production for market, whether for food, fiber, fuel, or any of the other reasons we put land to productive use, and to systems engaged in the management of land for production.

In this context, it's reasonable to divide plants into two basic categories, crops and weeds. Any such system must be able to differentiate between the two and nurture crop plants while eliminating or at least suppressing the growth of weeds. Differentiating plants is more easily accomplished after they have grown beyond the seedling stage, but controlling weeds that grow from seed is more easily done while they are still seedlings. So one design choice is whether to attempt to differentiate seedlings and eliminate weed seedlings before they've had a chance to root deeply.

Differentiating seedlings can be made considerably easier if you know very precisely where the crop seeds have been planted, so anything appearing more than a very short distance from one of these locations has a high probability of being a weed. Beyond that, a robotic gardener could use visual information (from gross morphology to the vein pattern of the seed leaves) and/or sniffing for volatile compounds. Visual information can be acquired from a considerable distance, relative to the size of the seedling, whereas chemical sniffing requires close approach, and is generally better accomplished by a small device.

Either way, once the decision to take out a seedling has been made, there remains a choice of methods. If the device which detected it is small, light, and locally supported, meaning that its weight rests on nearby soil, then a mechanical extraction of the seedling from the soil (uprooting it) may be the most reasonable approach, the main concern being that that it grasps the correct seedling.

On the other hand, if the device is remotely supported, meaning that it is essentially suspended amid the foliage, mechanical uprooting may still be an option, if it also possesses one or more quick-moving appendages, but the time involved will be a more pressing consideration, as a remotely supported device would necessarily represent a larger investment, so there will be fewer of them and each must handle a larger area. But other options are available to a remotely supported device. It might use a laser which can be retargeted as fast as a mirror can be repositioned, or a miniature turret that fires ice pellets, and if it uses an arm, that arm might slice through the seedling with a thin jet of high pressure water rather than grasping it.

So much for weed seedlings, but they're the easy example. Let's consider weeds, like some grasses and shrubs, that spread by rhizome. A rhizome is a horizontal root, running just below the surface, occasionally sending up stems which appear from above to be independent plants, but which are actually part of a larger, robust organism. If a plot is heavily infested with plants that propagate by rhizome, they cannot be eliminated without also destroying whatever crop was in the ground at the time. The approach that works most reliably is to frequently survey for emerging stems of these plants, pulling them up with as much of the rhizome as comes along fairly easily, and to keep at it until the rhizomes run out of stored energy for putting up new stems and rot in the ground. This is an operation that really can't reasonably be performed by a locally supported device, because it can require significant force to pull up such a stem, much less the attached rhizome. A locally supported device might clip them off at the soil surface, but to be effective, that would need to be repeated even more frequently than the uprooting.

Something a small, locally supported device might do would be to apply very small doses of some specific herbicide, such that it would be absorbed into the rhizome itself before killing the stem, but this begs the question of whether herbicides are to be used at all. (If they are to be used, then direct application of small doses to the weeds to be controlled is the obviously best approach.) Something a remotely supported device could do that a locally supported device really couldn't, would be to use an electromagnetic sensor to trace a signal transmitted from one section of rhizome to locate another spot where it could be exposed and then heated by passing an electrical current through it. Another option would be to inject steam next to the stem, killing the stem and a short segment of rhizome.

If we were to go on to consider other operations, for example harvest and dealing with the coarse plant material left over after harvest, it would quickly become apparent that the larger, remotely supported machines are necessary, whereas the smaller, locally supported devices are probably optional, although the most efficient approach might well be to use both in a complementary fashion, the gardening system mentioned earlier, perhaps even including insect-sized devices that fly among or crawl over the plants themselves.

Strictly speaking, devices suspended from a wheeled platform that always follows the same tracks, a practice which is beginning to gain traction in precision agriculture circles, would qualify as remotely supported for the purpose of this discussion, even though part of the surface of the field is sacrificed to supporting the weight of the machines. Where the wheels of those machines don't run, the soil remains uncompressed. Placing gravel on the tracks they do use would help limit damage. Another option would be to install rails or troughs that double as channels for water transport. Still another option would be to support the platform on legs that only ever placed their weight on particular spots. Any of these options would help avoid the rutting of continuous paths that could lead to erosion.

Other design choices include sensors and the sorts of information gathered and the types of manipulators provided. A garden is a very complex environment, most of which is delicate, and while that delicacy makes the design and control of manipulators more difficult than it would otherwise be, getting adequate information into the machine, and deciding what operations to perform, is by far the greater challenge.

Laser scanners of various sorts could prove very useful in mapping foliage. Imaging radar could help locate stems that are hidden by foliage. Video, particularly if high definition not only in pixel density but in color depth (and ideally in splitting the spectrum more finely than the usual RGB), combined with telescopic optics, could make differentiation of seedlings far easier. Chemical sensing, mentioned above, could be used, for instance, to determine the ripeness of fruit and to detect the presence of some infestations and diseases. Very acute hearing could help with the discovery of insect activity. Infrared video would help with locating warm-blooded animals. Touch would be important in making it possible for manipulators to reach through foliage or pick fruit without damage.

All that said, the most fundamental choice isn't any of the above, but rather what sort of management regime to support. I'll address this issue in the next installment.

what operations should a ‘cultibot’ be able to perform?

The list of necessary operations might seem pretty straightforward. A robotic gardener or gardening system (more than one type of machine, each specializing in a subset of the overall range of operations) would need to be able to accomplish the same basic tasks as a human gardener: seedbed preparation, even if it's only a narrow hole through mulch and/or ground cover; planting, watering, weeding and/or suppressing weed growth; applying nutrients in one form or another; intervening to control animal pests and diseases if they threaten to become a problem; tracking the progressing ripeness of the crop and combining that information with the weather forecast to decide when to begin harvesting; and, of course, the harvest itself. Also, to get the best possible productivity from the land and the greatest benefit from the investment in a robotic gardener or gardening system, that machine or system should be able to start seedlings in a greenhouse and then move them out to the open field, inserting them through mulch and/or ground cover.

Then, too, there are other operations which are either optional or less commonly understood to be necessary: either collecting leftover coarse plant matter (corn stalks, tomato vines, and so forth) for centralized processing (grinding, optionally followed by anaerobic digestion producing methane gas, followed by aerobic composting) or simply grinding it into small bits in the field and leaving it where it falls, for mulch; limited relocation of soil to create and maintain a topology which slows the runoff of excess precipitation, without creating pools that persist hours or days after the latest storm has passed; relocating larger stones found in the soil to create permeable dams across grassed drainage ditches, where they can help slow water movement and help prevent it from cutting through the sod; and dredging muck from the bottom of surge ponds and distributing it over the field, to recover nutrients and prevent them from overloading any permanent ponds, much less passing downstream.

But, if you're going to have robotic machinery doing all of this, there are other operations you might want it to perform, operations which machines that have sensors and processors and well as effectors can relatively easily be made capable of performing. Examples might include: keeping detailed records including when each seed was planted and what the soil temperature and moisture content was at the time, when the sprout emerged from the ground, and how fast it grew; monitoring each plant for early signs of infestation, disease, nutrient deficiency or toxicity, waterlogged soil, and so forth; and targeted pruning to control infestation and disease without drastically reducing leaf area.

In the next installment, I'll begin to address design options and mechanical details relating to making machines capable of performing the basic operations listed above.

In agriculture robots replace job vacancies

Here's the bottom line…

So as new types of machines find their way into the fields, rest assured that they are not, for the most part, displacing workers who would otherwise be in those fields, but rather, in some cases, moving them into more technical work as robot tenders, and in other cases taking over work that fewer and fewer people are willing to do for the money it pays, and that, for those few who are displaced, there will be other farmers nearby anxious to hire them. Meanwhile, a new industry will be germinating.

See the full article on Robohub.org

What's in a name: sustainable agriculture vs. agroecology

Names are important in much the same way that book covers are important; they suggest what lies behind them. But there is an additional way in which names are important, which is their resilience in the face of attempted cooption. Does the chosen name continue to robustly represent what it was originally intended to represent, or does its meaning become diluted by misapplication?

There are quite a few names available for use in referencing the practice of growing food (including herbs and spices), flowers, animal feed, forage, fiber, fuel, lubricants, and chemical feed stocks, all in harmony with nature, most of which take the form of an adjective followed by one of the following nouns: gardening, farming, horticulture, agriculture, viticulture, etc. The set of adjectives in use in this manner includes biodynamic, biodiverse, organic, regenerative, resilient, and sustainable. (To complicate matters further there are also some terms relating to specific practices, like permaculture and polyculture, that are important to any such discussion.)

For many of us, there is a tendency to use adjective-noun combinations from this set almost interchangeably. We understand what we're attempting to invoke better than we understand the nuanced distinctions between them, so it seems to make little difference, except that this results in a profusion of terms for essentially the same thing, and some of these term combinations are more susceptible than others to being used in ways that lack clarity or are even contradictory to what we would mean by them, meaning that there is a danger that others hear us saying something different from what we meant.

“Sustainable agriculture” is, unfortunately, one such term. While it originally meant something like ‘a set of practices which can be continued forever without wearing out the soil or reducing yield’ it has come to mean other things to other people, including something on the order of ‘a set of minor adjustments that allows agribusiness to continue doing essentially what they're doing now for another decade or two without catastrophic collapse’.

Another term which is more difficult to fully comprehend, but less susceptible to misuse is “agroecology” (“agroecological” as an adjective). Properly understood, it implies all of the other adjectives listed above, except some of the more arcane aspects of biodynamics, and adds one important concept, cooperation between human-managed production and the native ecology of the land in use, such that you can't tell where one ends and the other takes over.

Just as there is a confusion of terms with respect to the practice of managing productive land in harmony with nature, so too there are many terms for robots designed to assist in this process, nearly as many terms as there are robots of this class, it would seem. Rather than slog through the list, I'll get straight to the point, which is that, after years of using “cultibot” and “cultibotics”, I've found another pair of expressions that I prefer. “Agroecological robotics” nicely defines the field in a manner that resists dilution, and “agroecobot” works well enough in reference to actual machines. I'll probably continue to also use “cultibot” and “cultibotics”, but understand that I intend them only as shorthand for machines designed to assist in the practice of “agroecology” (which itself implies biodiverse, organic, regenerative, resilient, and sustainable practices), with a view to making that practice scalable to millions of acres.

CMURobotics RI Seminar: Mel Torrie of Autonomous Solutions

As guest speaker for a CMURobotics RI Seminar, titled Lessons Learned Bootstrapping a Robotic Vehicle Company, Mel Torrie of Autonomous Solutions (Petersboro, Utah), describes how he got into robotics in the first place, why he made the jump from academia to a startup, how that startup survived their "near-death experience", what the company has been doing since, and what he's learned along the way. There is a strong agricultural theme, both in his original motivation and in the history and current operation of Autonomous Solutions.

Technology for its own sake vs. benefits

On using robots to make gardening scalable to millions of acres...

You might wonder why I want to turn land management over to robots. Is it because I'm such a geek that I think everything goes better with robots? No, not really. Sure, I think the technology is cool, but I'm not eager to factor human beings altogether out of any activity, not even those that are dull, dirty, and/or dangerous.

I am, however, eager to see the benefits of replacing methods designed to spread a human operator's time as thinly as possible with methods which reintroduce attention to detail to plant cultivation. Granted, that attention would, for the most part, be provided by robotic sensors, processors, and algorithms, but that has an upside as well as a downside.

The downside is mainly that it's unfamiliar and we don't know whether we can trust it. The upside is that robots aren't limited to human senses, but can go as far beyond them as available technology will support, providing information not directly available to us, and they also aren't limited to the time a human operator can afford to invest, provided they are capable of autonomous operation. Potentially this means that instead of a single machine running 40-60 hours per week, you can have many machines running 24/7, vastly increasing the available machine time per land area.

Combine that rich sensory information and machine time availability with manipulators capable of performing basic gardening operations (planting, weeding, pruning, harvesting, saving seed, ...) and you have a platform justifying the effort to develop higher level software which supervises beneficial plant combinations in space (polyculture) and time (crop rotation), which is capable of mixing annuals with perennials (permaculture), which makes room for native plants (particularly those that are threatened or endangered), which also makes room for animals without allowing them to ruin crops, and which can make sure there are enough flowers, throughout the season, to keep pollinators healthy.

Such a system could also learn from experience, even setting up intentional experiments, maintain the genetic diversity of crops, and accelerate the creation of new strains in response to changing conditions. It could also provide exquisitely detailed information in support of operation management.

Technology of this sort would make for a far more varied and interesting landscape (biodiversity) and greater variety of production (diversified income), supporting a more well balanced diet for those dependent upon it. It could also dramatically reduce the energy and other inputs used in crop production, all but eliminate soil erosion and the airborne dust and stream contamination that result, reverse the loss of organic matter in the soil (improving its water absorption and retention and contributing to the sequestration of atmospheric carbon), save many endangered species from the brink of extinction, and bring the practice of agriculture into parity with other aspects of the modern world in its sophistication and the respect it commands, helping to enhance rural culture.

So, yes, that would be very cool technology, but it's really about all of the benefits that could be realized through its widespread deployment.

John Robbins speaking at Stanford

John Robbins speaking at Stanford, before the election, about California's Proposition 37, which would have required labeling of GMO content in foods, and related topics. (Mr. Robbins' talk begins at 3:30.)