Sunday, March 18, 2012
I want to say a little more about other uses for PRT technology besides moving people. Freight has long been contemplated, and looks attractive as an after-hours revenue generator, but has the same critical mass problem as carrying people, only more so. Only after there is an extensive network is it of much use. In the last post I said that the concept of SMART (Standardized Multi-axis Automated Rail Transport) applied to more than Automated People Movers. Well, it also applies to more than freight. It applies to anything and everything that needs to be picked up at point A and sent non-stop to Point B within a matrix of possible origins and destinations that are most efficiently accessed using 3D routing. A prime example is manufacturing.
The images above represent a greatly simplified assembly line. On the left six parts (in red) are added to a product moving along an assembly line (blue) in various stages of completion. The right side shows what happens if the product comes in just three variations. No extra parts, just some hypothetical process variations at the points where the blue lines diverge. Now, when same parts are added, paths must cross. If this is done on an actual work floor, this crossing is quite literal, causing someone to wait, go over or go under. This situation is usually handled by stockpiling supplies, so such crossings are less frequent. But consider how this solution is analogous to city buses. They can move many passengers through an intersection at once, but are big and cumbersome. Of course we know what happens beyond a certain critical mass. At some point, anything other than full-speed, non-stop movement will create a cascading gridlock effect. If the parts are bulky, stockpiling them may be impractical in any case. So with that in mind, consider the illustration again, but this time with dozens of variations, instead of three, and many dozens, or even hundreds of parts, instead of six. This makes routing and staging parts and positioning work areas a real nightmare. It would take me a week just to draw it!
Some years ago, back when CNC was a brand new thing, I was given a tour of a cabinet factory. The main feature that you couldn’t ignore was that the place looked like it was designed by an insane ski-lift maker. There were cabinet pieces floating past all over the place, some hanging on hooks, and some in baskets. These were all going in different directions, all guided by long moving chains hanging at various levels from a superstructure attached to a very high ceiling. It was quite a sight! I think cabinet making is a simple enough process that hopefully it will help me illustrate my point.
The cabinets largely started as 4x8 foot sheets of material. You see, the secret to cabinets is that there are very few changes in saw settings. Be it a 48” or 24” cabinet, the sides, for example, are the same height and depth. And since most dimensions are repeated again and again, it only makes sense to set various saws one time and cut large numbers of pieces. And so it was in this factory. Material came in on forklifts and was rip-cut to various standard widths. Then those pieces were cut to lengths for the various sizes of cabinets. Most of the pre-finished pieces would go directly to an assembly area that was just for one or two specific cabinets. So there were many assembly areas. But cabinets come in various paint or stain finishes. All face-frames and doors and drawer fronts for a specific order, therefore, had to go through a finishing process. So they needed to be collectively detoured to a finishing and drying area and then re-sorted by sizes and sent to their respective assembly areas where they would join the prefinished parts and preassembled drawer boxes, which would be made still elsewhere in the factory. After assembly, the finished cabinets would be push on roller tables to a nearby boxing station, and then grouped with other sizes to make up an order or truckload. Cabinets come in four or more standard sizes, along with corner units, sink bases, and banks of drawers and all sizes have corresponding upper cabinets. And if all of this isn’t enough, let’s not forget the number a door styles that are typically offered!
Now consider all of this this against the illustration, and you will appreciate the problem. There were many dozens of work stations, some organized by component, some by cabinet size, some by finish, and some by purchase order. The only way to move things around efficiently was to have skyhooks that would whisk parts to the proper station, and do so without clogging up the shop floor. Cabinet parts would go around and around until someone took them down.
The same root causes of traffic on streets are the dilemmas that the cabinet factory suffered. These are generic problems that come from conflicting directional movement on a 2D (ground level) surface. As I think I may have mentioned in a previous post, the same problem extends all of the way down to circuit board and even computer chip architecture, and I have been told that there are aspects of graph theory that are used to help solve these difficult issues. Planning a factory, it seems, is a real science. I read somewhere that the Chevy volt assembly line is over twenty miles long. They are probably counting production lines for the sub-assemblies, but still this gives you an idea of the scope and complexity of this issue.
PRT grid would be used to prioritize pick-ups and deliveries around the factory floor. Every stockpile of pieces or sub-assemblies at every workstation would be automatically replenished, and then the resultant parts taken away to the next staging area. PRT traffic management, it turns out, is very close to industrial process management.
We are in the early stages of the robot revolution, and most are still essentially mechanical arms bolted to a floor. Any work piece has to come to them. Lately, however, some are becoming more mobile. Gaining popularity is what is called a gantry robot, because it can move itself along an overhead beam. But these are still tethered by power and data cables. While these robots are handy for assembly, because they can fetch parts, they can only go so far. The next logical step is the untethered “railbot.” This has not already happened, in part, because the key to maximizing the effectiveness of such a system is to make it route-switchable, electrified rail, but still with full data transfer capabilities. (Gee, now where have we seen that problem?) Make no mistake, this is coming to manufacturing. Non-switching, somewhat limited versions of such overhead “railbots” are already used to lift and tilt cars during assembly, as shown in the picture below.
Refrigerated warehouses already use similar machines to fetch frozen foods without requiring humans to work in the cold. The PRT maker 2getthere is a subsidiary of company that makes self-navigating forklift type vehicles. Making a grid over the factory floor and extending track all of the way to remote warehouses promises to make an extremely efficient and versatile manufacturing platform. Remember, the overhead bogies can either carry materials or have their own robot arms or both. As long as the bogie can be made to precisely locate itself and then lock on to the track, it’s suitable as a base for a robot arm. In the case of the cabinet shop, for instance, the assembled cabinet faces would be not just carried into the finishing room, but held for spraying and delivered to the drying area without human intervention. We are talking about an amazingly flexible system here.
The holdups to deployment are very similar to obstacles facing PRT. Like vehicle makers, robot makers do not really want the business of constructing track or controlling traffic, since that would demand a totally different, more locally oriented business structure. And track fabricators certainly don’t want to get into the robot or vehicle business either! Some great ideas just don’t fit with existing business structures.
That brings us to a point about the “S” (for “Standardized”) in SMART. One key is to have a standard track-to-vehicle interface, so these businesses can concentrate on what they do best. Currently, assembly line equipment is generally a huge, one-of-a-kind investment that may well go to the scrap heap when it is no longer needed. Meanwhile, product life cycles are, in case you haven’t noticed, getting increasingly short. A modular solution can be reused, reconfigured, and even eventually sold off at a reasonable price, like any other equipment. But modular pieces need to fit together, and that means a degree of standardization.
There was a time when getting a computer meant special rooms and teams of engineers to hook everything up. Over time, the system evolved into a something much more modular, and therefore flexible and simple. What geeks call “plug and play” is, no doubt, the destiny of automated manufacturing as well. It just happens that we, in the world of PRT, have long contemplated and largely solved the problems that they, in manufacturing, are just starting to understand that they have. And did I mention warehousing and package sorting?
When I talk about needing non-profit organizations, government grants, academia and corporate partners, it should be kept in mind that there is a lot of benefit to taking part in this transition. Self-navigating, non-stop 3D transportation is the ultimate in efficiency, both in terms of time and energy consumption, and this, in one way or another, will always mean profit. This application, unlike PRT, is for a closed, private sector application where there are a huge number of companies that might benefit. When I talk about an NPO umbrella for all of this, let me just say this: (I would refer the readers to the previous post for background)
The companies who would benefit the most from this technology need some kind organizational framework that enables them to participate and keep abreast of the work that others are doing. The tax exempt part of this really isn’t the point for these players, they can write everything off anyway. But I can see absolutely no reason to make this framework anything but an NPO, especially early on. This is not really anything revolutionary. The world is awash with such consortiums, and it would, in practice, be nearly impossible to equitably divide up any profits anyway. (An example of a for-profit consortium that had profit dividing problems is the original Airbus, and an example of a large NPO type consortium for advancing technical expertise is Sematech). This particular endeavor, I might add, also has a lot of “green” and “public good” aspects to it, and so would be well situated to raise money from individuals, charitable organizations and governments, not to mention possible participation from universities… I mean we ARE talking about saving the planet, after all…
And yes, I realize that this whole thing, at this moment in history, is an audacious pipedream. I also know that every revolution has to start somewhere. For lack of a consortium, I am, at least for now, willing to do its work singled-handedly, at least in respect to exploring the pros and cons of various design choices. A consortium of one!
I guess the bottom line here is that the ability to “airlift” many objects, non-stop, in a coordinated way, is a very big deal in many human endeavors, not just people. Robots are becoming more mobile and modular every day. So remember, you heard it here first: Railbots are coming to get you! (at your local station, of course!)
Sunday, March 4, 2012
There is a problem with the PRT business model. It is not scalable enough to really make an impact, because it is inherently a multifaceted local endeavor. For the foreseeable future, each new project will tend to dominate the PRT provider’s attention, at least until it is up and running. That is just how construction and development based projects are. This is not to say that a PRT provider cannot grow big enough to handle multiple projects at once, but rather to say that such growth cannot be rushed.
There are models that offer at least partial remedies. For example franchising might have potential, and partnerships offer another avenue for more rapid growth. The normal way rapid, revolutionary change usually occurs, however, is from the bottom up, where many self-serving actors can chip away at a problem independently. So how can this be done in the PRT world?
Well, for one thing, whatever oversight is required must be kept to an absolute minimum. McDonalds didn’t get so big by trying to manage the day-to-day affairs of individual restaurants from the central office! So what would this minimum be? Let’s start with a process of elimination.
First, the track - which certainly would involve a lot of local collaboration in any case. It is my belief that track can be installed for under 2.5 million USD per mile, and that the lifespan is such that only a small fraction of the fares would be required to pay down these costs. So can this constitute a viable, stand-alone business? Let’s run some numbers. Imagine we are counting passing vehicles on a one mile stretch of track and on average, during a sixteen hour day, there is just 1 passing vehicle every ten seconds. If the track provider gets paid just 12 cents each, that is $691 daily, or over $252,000.00 annually. That is enough to pay the track off in about ten years. The track should have a life span of many decades, so after it has been paid off, it represents a pretty nice little cash flow! So far, so good.
Let’s turn to stations, and let’s assume that private land is involved. If landowners can make a small piece of the fare, say 20 cents per passenger, and station construction is a turn-key proposition, (probably by being an add-on contract for the track guys) then perhaps this too can be a standalone business model. Let’s assume a low volume, bus stop style station that can be built, including some feeder track, for $150,000. It has an average usage of only one passenger per two minutes with the station getting 20 cents of the each fare. That’s over $35,000 annually, so the station could be paid off in under 5 years. (To make this still more lucrative, local property tax inducements could be offered as well, something that most cities could pull off without a lot of opposition. Also, let us not forget the value of the increased pedestrian traffic to the landowner.
The vehicles are probably best made by a consortium of really big companies that want to gain good will and free advertising while making a buck in the meantime. Once again, a piece of the fare would go to this effort. I say consortium because, at least as I envision it, the part of the vehicle that is not the passenger compartment is essentially a mobile robot, and might fall better into the expertise of the people that build the automobile assembly line equipment than the vehicle maker per se. Readers of this blog will appreciate that my vehicles seem quite ambitious; however even a few cents per mile buys a lot of vehicle over years of daily service. For example, at 11¢ per mile (100 daily miles) and $0.45 per passenger, (say 50) a vehicle would generate $33.50 daily, which comes to $12,227 per year. At, say, $60,000 each, that is still only a five year payoff cycle, and these vehicles ought to have much, much longer lifespans than that.
So what are we up to? $0.65 to board and $0.23 per mile? I guess we better add 13 cents a mile and a nickel for station maneuvers to pay for electricity. OK. Now we’re up to $1.06, and we haven’t included maintenance or monitoring, or even finance costs, but this is not supposed to be anything like a real feasibility study, and I want to get on to the next part, so bear with me.. (I’m not sure that some of that can’t be passed off to the local transit authority anyway, but let’s not deal with that now…)
As I said in the beginning, the way to make a system rapidly expandable is to allow bottom-up, decentralized growth, by minimizing or even eliminating the responsibilities at the top. Obviously there is a lot of coordination involved in PRT deployment, and this area alone could be the subject of many, many posts. Let me just say, though, that I envision the top of this totem pole to be a non-profit organization. (NPO) Such an organization would develop the standards necessary to allow compatibility between the disparate corporate players and work to improve the system over time. The organization would also work with local transit authorities, provide training, etc. I would note here, for those not familiar with NPOs, that they can behave very much like for-profit companies, except they do not pay taxes. They have salaried management and staff, can award contracts, etc. It is my assumption that there is some way to levy a fee from PRT fares to help support such an entity, either directly or indirectly. Any lawyers out there? The NPO would play a key role in developing the system by soliciting help from academia and industry, as well as fund raising and promotion.
If all of this seems complicated, compared to just forming a PRT company, let me point out that an NPO has a definite advantage when it comes to raising funds and issues of trust. Person(s) seeking to create a for-profit PRT company can still do so while being affiliated and perhaps even drawing a salary from the NPO, although conflicts of interest must obviously be carefully avoided. Right now PRT companies are starved for R&D money. That is because they want to have all of the profit for themselves, and the result is products that look like they were… er… starved for R&D money. I would suggest getting a smaller part of a much bigger pie, divesting one’s self of the parts of the PRT effort one doesn’t want in the first place. A great deal of this stuff is, after all, clearly in the public interest. But government and private grants have a real problem going into PRT development projects since there is no entity to receive them, except for-profit corporations whose fiduciary responsibility is the enrichment of their shareholders.
Standardized Multi-axis Automated Rail Transport - (SMART) - That is my take on what is worthy of public research and development funds. The concept is simple. We need an all- weather way to move objects longer distances in full 3D rapidly and efficiently. 3D because our surface world is too crowded to permit non-stop movement, and getting to and from ground level needs to be as easy and straight forward as possible. This is not just about moving people, but rather the transit solutions are a sub-set of SMART development. Other areas of development could include warehousing and freight delivery, for example. The common denominator between all such subsets is the multifold increase in energy and time efficiency, something all responsible citizens and their respective institutions should want to support.
Movement of people and freight is at the very foundation of society itself and the efficiency of our means of transportation are paramount to the prosperity of every one of us, not to mention the sustainability of our, and every other, species on this planet. I can see no other effort so worthy of philanthropic, government, and corporate support. Now I know the numbers I throw out above are hardly worth the paper they aren’t written on, but the ridership numbers are, you will agree, very modest, and I was, after all, just trying to get readers thinking. To make this work, the independent business models have be so lucrative that they are like taking candy from a baby. Independent businessmen need to have enough to gain that they will relentlessly pursue each available lucrative route. The object is to iron out every legal, fiscal and technical challenge and lay the opportunity at the feet of free enterprise. I know this is a huge challenge, but what other scenario is out there that would enable hundreds of cities, worldwide, to start building PRT infrastructure at once?