Older blog entries for cultibot (starting at number 3)

a compromise between rails and walking directly on the ground

If the area to be covered by a farmbot is known, and limited, it might be tempting to outfit the land with rails and the machine with wheels to match, to keep the weight of the machine off the soil and improve its mobility, but in areas where production is constrained by low precipitation or short growing seasons this could prove uneconomic.

A possible compromise solution would be to use long, spider-like legs to span between the tops of posts, a foot or two above the soil surface, or even just low mounds of gravel. Providing this much infrastructure would not only prevent tracking and compression of the soil over most of the area, but it would help the machine locate itself in the field, since the posts or mounds would have known, static locations.

While such machines might move more slowly than if they were equipped with wheels running on rail, the logistics of having several working the same field would be simpler, since they could just walk around each other.

2 Feb 2011 (updated 2 Feb 2011 at 17:27 UTC) »

cascading distributed network

Another such idea (taken through initial development as a thought experiment), in this case one that you'd have to be a chip hacker or microcode programmer to actually implement, first saw the light of day years ago, on The WELL, and then more recently in a topic in the Robots Podcast Forum (since closed).

This one is about very efficient addressing and message passing through a processor network having arbitrary topology, using only the minimum necessary number of bits for each step in a path, and automatically generating a return address, which can also serve to identify the source of the message.

It's recently occurred to me that this idea might be particularly applicable to robotics, where machines might have a separate processor to control every major joint and sub-system, and need to pass messages directly between them without going through a central switch, to keep latency manageable.

Such a network could also accommodate situations where hardware needed to be hot-pluggable, added and removed as the situation required, since newly attached hardware would automatically acquire predictable addresses and, in the case of removal, remaining hardware would always have return addresses for use in sending "cannot deliver, that path is closed" messages.

2 Feb 2011 (updated 2 Feb 2011 at 16:56 UTC) »

examples (and the limits) of design through imagination

At the beginning of March, 2009, two such ideas (designs or simulations running inside my head) had been taking up cerebral resources for some time, weeks or months, so, since they weren't going to be getting any better in the absence of something more tangible, either a CAD model or a mockup, neither of which I had time for, I decided to offload them to one of my blogs, in the hope that someone else might benefit.

The first is essentially the miniature equivalent of inserting an air hose through the tread of a tire at a very shallow angle, nearly tangent, to create a dust barrier via the resulting airflow, with the idea of using it to keep dust off of camera lenses and the like.

The second had its origin in the knowledge that the closer you get to the pivot point of a lever the more force is available. Applied to a robotic manipulator, this means that the outer tips of the 'fingers' should be more sensitive and delicate than segments closer to the 'wrist' (the point of attachment to the supporting arm). Conversely, it also means that those inner segments might be used where more force is needed, as in clipping through the stem of a woody shrub. Inconveniently, stems in need of clipping come at odd angles, so if a shear only operates in a single plane that plane may need to be rotated as much as 90 degrees in moving from one clipping to the next, which might require repositioning the entire machine, which could slow down the operation considerably. Giving the manipulator a set or semi-rotatable digits, that can pair in two different X-shaped configurations, 90 degrees opposed from each other, could provide as many as six shear planes without any rotation of the manipulator unit as a whole. This would allow a pruning robot to move from one clipping to the next with a simple repositioning of its digits.

30 Jan 2011 (updated 2 Feb 2011 at 16:08 UTC) »

Further Introduction

Not mentioned in my intro is that I received a Bachelor's degree in biology in 1980. I'd hoped to return to school for a second degree in engineering, but that never happened, and I spent several very hard years essentially trying to punch my way out of a cognitive bag composed of academic categories, and the emotional baggage I attached to each.

The resolution I found came through the discovery of General Systems Theory, itself an academic category, but one that points to the general applicability of a collection of fundamental concepts. Thus armed, I approached learning with renewed confidence.

It wasn't long after this that I began to become obsessive about computer processors and software, always with an eye to how they might apply to robotics, since I was already interested in mechanizing and scaling up horticulture. Being possessed of a vivid imagination at least with regard to machinery, I built many machines and set them running in my mind, frequently sharing descriptions of these designs with whomever would listen.

For me that was the missing ingredient, collaboration. With no one to share my enthusiasm, it was wet blankets wherever I turned. It's only recently that I've begun to feel like I might have found my tribe.

But I'm not a tinkerer; I'm out to change the world, by replacing big, dumb machines with smaller, smarter (wiser!) ones, beginning with agriculture.

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