Sunday, December 13, 2009

63> ULTra – Architecture and Iteration

There has previously been, in my mind at least, some question about whether ULTra is really PRT. After all, the 40 km (25mph) speed is hardly “rapid”. And the distances that passengers will be willing to travel at those speeds are somewhat limited as well, although I suppose they are far enough to be legitimately called “transit”.

I started writing this post with a number of negative suppositions. I have previously criticized the ULTra design for being little more than a golf cart, and wondered aloud what the advantage of automating such a vehicle really was. Actually I was about to call for ATS (The company that makes ULTra) to consider a purchase of company like Taxi 2000, or PRT International, as a way forward out of the constraints of it’s present design limitations. I am forced, however, to reconsider.

I have been selling the ULTra designers short, I now believe, and this is why.  Many of the aspects I don’t like about ULTra are truly intermediary. They will not stop ULTra from becoming much better (and more versatile) in future iterations. It seems that the designers over at ITS have a motto of extreme simplicity and conservatism. Anything else is kept “close to the vest”.   Here is one example. The traditional steering, (as opposed to track constrained steering) at first glance, would seem to have all of the negatives of cars. It would skid on ice, for example. Safety issues would seem to prohibit any kind of speed with an automated guidance system. The idea of a track would seem SO much better than trying to center the vehicle with lasers and sensors. So why didn’t they do it? Well for one thing, tracks are less versatile, because they prohibit the vehicle from being able to move freely on any paved surface. But it is mostly, I believe, because they didn’t need to. Tracks would offer the potential of much higher speed but they don’t need speed. It’s only an airport “people-mover”. But the fact is that a track or guide rail is still perfectly compatible with ULTra. They just chose not to use one, for now. Lasers can be turned off, but you can’t easily pull up the tracks. Therefore lasers win. If and when speed becomes an issue a simple rail that sticks up under the center of the vehicle could be added, with minimal modifications to the vehicle.

One interesting aspect of ULTra is that it could presumably be driven away by a human operator, using a plug-in video game style controller. This would seem like a natural way for mechanics to move vehicles around a maintenance facility, for example. That raises intriguing questions about dual-mode, doesn’t it?

Don’t be too put off by the weight. They are using the old, heavy, lead-acid batteries. But once again, the only trade-off has been to design-in some extra space. They can upgrade to Lithium-Ion or even third rail at any time. It was explained to me that track electrification was deemed too costly, but I can’t help but wonder about partial electrification, so that the batteries could get some on-route charging. The possibility of easily swappable batteries also comes to mind.

I also hate the track, especially as seen from below. That would seem to be a hard sell for city streets.  This, also, is not really an issue that can’t be much improved. There is nothing that says that the track must be massive concrete, for example, although noise could become an issue of the track was pure steel. There is a gradation between rails and roads. If redundant road area (anything not in line with being directly under the wheels) is removed you are left with a pair of very narrow beams – seems pretty much like a pair of rails to me. ULTra can theoretically drive on such “rails”.

I guess the lesson here is to beware of false choices. This does not just apply to Ultra. I was bemoaning the huge turning radius of the Anderson designs and a similar thought occurred to me. There is nothing inherent in the concept that prohibits tight turns. It I just that it necessitates a more complex bogie than is called for in the current business plan. 

It is easy to look at a system from afar and the hard choices that have been made and to rap them up as defining that system, rather than see them as a collection of business decisions. ULTra is not a clunky, slow, heavy vehicle on an ugly, massive roadway. ULTra, like other systems, is an architecture first, and the rest of it is a means to salable iteration of that vision. This architecture, I am finding, is surprisingly tweekable.


afransen said...

I think you raise a lot of good points, and perhaps ULTra will be a good solution for more applications than people give it credit for (I was actually struck at how ultra-conservative they were based on their promotional materials). However, they do have the flaw of having a supported architecture, which does have some serious, inherent flaws as you've pointed out, elsewhere. Is this what you mean when you say they should acquire another PRT firm; they should acquire a firm with a suspended architecture?

Dan said...

Dan The Blogger Responds -
No, Alfransen, I take that back. On the face of it, the Anderson designs seem much more sophisticated, and I thought that the one with the track record and the one with the seemingly better technology would make a good team. The problem is that I’m not sure that the slim monorail/linear motor design is of sufficient advantage (as compared with the flexibility of ULTra) to be of value. Look at it this way. If Ultra married Skyweb Express and they had a baby it would look like Vectus, and they have yet to sell that system even though it’s been tested for years.

I also cannot say that they have anything to gain, from a business standpoint, by getting into hanging systems. They first need a much faster, lighter, vehicle, with a reduced guideway profile. That would help them get into the general public transit market. They are, at present, a company most likely to find business on private property, such as campuses, hospital complexes, and other airports. That doesn’t matter though, because cracking the public funded transportation market requires a well-established company with lots of projects under its belt. It really doesn’t matter that hanging is the way to go theoretically. It won’t bring in he next big contract, so they won’t (and shouldn’t) concern themselves with it. Later on, we can always “pimp their pod” with a hook on the roof!

afransen said...

I suppose you're right, but any reasonably successful PRT will impose an architecture we might be stuck with for a long time, hence the legacy of right-hand drive countries vs. left-hand drive countries. We are stuck in a bad equilibrium. Same goes for the old railway days, where every railway used its own gauge. These are bad equilibria that take a huge amount of effort to escape once they are allowed to firm up.

So, I can see the appeal of just getting any PRT out there, regardless of its inherent flaws. But there's also the danger of not correcting those flaws when the chance arises, and being stuck with a suboptimal system.

akauppi said...

...and same goes for the mobile phone systems, as well.

We're "stuck" with GSM variations, CDMA and who knows what. It's a partial hassle, but not too bad a situation.

Personally, I prefer getting systems "out there" to overdesigning them in a cabinet. That never ever seems to bring much good (though GSM is an exception, but that was based on _loads_ of practical experience from the NMT network).

If we look at PRT as "horizontal elevators" instead of as mini tramways, there shouldn't be a problem in maintaining multiple non-compatible systems even within the same city. Anyways, I see this always from a service standpoint - the companies should not offer a track. They should offer a transportation service. Like ULTra actually does.

cmfseattle said...

"Our mature democracy favors incremental change while resisting large-scale innovative
change." (p.13)

it will be interesting to see what happens in San Jose.
San Jose Airport - $4M Study

Morgantown: OPERATIONS (p.11)

Jay Andress said...

Dan, Hang in there (pund intended)I just think that the suspended design will win out eventually for a number of reasons. Lightweight vehicles (which will increase fuel efficiency and speed) need to be "locked" in to the track. This ability to "lock" in to the track is easier with suspended systems. Another reason...the ULTRA and Masdar systems uses a recharging battery system which is fine for short distance and low demand systems (where vehicles can sit at the recharge stations) but the ultimate PRT/DM system needs live electric feed. The reason that ULTRA and Masdar can be supported is because they do not have electric feed systems. The safety factor is just too significant with individual vehicles traveling and crashing into live electric systems. If you look at the Magnemotion car designs , although it is a supported system they put the electric lines above the vehicles...for very good reasons.
The supported systems are "comfortable" for the public now because that is what they are used to...but the goal of a PRT/DM system that can achieve so much (150mph plus, 300% increase in fuel efficiency, complete oil independence and significant reduction in GHG) should be...needs to be... a suspended system. You cannot achieve the potential of PRT/DM with a supported system.


cmfseattle said...

TriTrack is an example of a supported system that is designed to exceed 150mph and does not include live electric rails on the guideway.

Dan said...

Dan the Blogger agrees.

Hello, gentlemen. It’s Thursday night and I still have no idea what my next post will be about, and I have a lot of other stuff to do, so I may very well address these issues further as a full post. I agree with everything that has been said here, though.

I was wondering… Where is PRT International in that San Jose RFI? What is the agreement with Taxi 2000? Do they compete head-to-head? In this symposium, Dr Anderson appears only briefly and just pushes his site.

Also, while we’re all gathered here, (if, indeed, we still are) any thoughts on my Wiki? Should I just do a Wikipedia of PRT? (I can, of course, seed the thing with entrees from the real thing, and other sources) or should I make it a tool for navigating new standards and design issues? Or both? Or something else?

I’m inclined to include some design work functionality, because the reasons for every little detail in complex machines are related to other issues. For example, a “wheel” relates to traction, bearings, bore, previous designs, rpm, propulsion, etc. Discussions of all of these subjects can be linked to the “wheel” page, enabling more intelligent and informed discussions about any current wheel design. Every aspect (pros and cons) of the finished design can be, therefore, foot-noted.

On the other hand, a generalized site would be a killer way to organize PRT links …I wonder. Is there is a meaningful way to split these functions in a single wiki? It seems like just not-cross linking the pages might be enough, Does the structure of a wiki itself mean that there is really no problem?

akauppi said...

Wikipedia of PRT would be wonderful.

Though, it makes me think, don't such exist already? The problem with Wikis in general is to maintain the high level of objectiveness, especially when a narrowed down area s.a. PRT would be discussed.

But the Wiki would indeed enable a more "flat" way of contribution and discussion than a blog does.

I have an idea about -eventually- making a book about PRT. It would be needed once the designs pick up, or it could already be helpful in cases s.a. San Jose and Sweden. Maybe the Wiki could "be" this book, describing the things one needs to be concerned with, in a balanced and entry level way.

If it becomes an emotional fighting ground, it will be more harm than use.

John Greenwood said...


I agree with your views about ULTra, "Two separated tracks" seems to me more versatile than a single beam either above or below.

I also agree with Jay Andress that it will be essential to trap the vehicle at higher speeds but I think this could be done as an add-on feature along with electrical pisk-up.

Super capacitors will probably be better than batteries, they are more efficient, last many more charge-dischage cycles, and have higher peak currents. The power/weight ratio is currently about a tenth of batteries. (Info from wikipedia)

Dan said...

Dan The Blogger Responds-
Thanks for your thoughts, guys. Akauppi, what you say makes a lot of sense. Such a resource is sorely needed. The amount of material out there is huge. Just compiling it in a format that could be easily used would do the PRT community a lot of good. I suppose part of my reluctance to start down this road is the amount of time it would take, something I have very little of. The fact that a wiki could be used to describe the reasoning behind design details would seem to be a very different thing. I guess I would need some kind of “gateway” to separate the two. Perhaps my “SMART” acronym (Standardized Modular Automated Rail Transport) would do. I guess the main problem is in alphabetical search. I don’t want someone getting bogged down in pages that deal in details for an ongoing project if they just want general info. Wikis don’t necessarily need to have unfettered public access on the editing level. I think an “invitation only” approach would probably be best. If you are serious about wanting to contribute content, either written or compiled, we should communicate further via email. Perhaps a wiki that is unconnected to my blog would be best.

Hi John – As I was writing the “SMART” acronym above I couldn’t help but notice the similarities between SMART and your ongoing “MAIT” effort. Is the only difference our design sensibilities? Anyway, I didn’t say that the two separated tracks is better, especially in respect to hanging, just that it has some significant advantages. Hanging is still the only system that truly minimizes ground level interferences of all types. In sprawling cities like Houston, Atlanta, and L.A., I believe most stations would be open-air, bus stop style or they wouldn’t exist at all. That would leave much of the city unserved. There just isn’t enough ridership (per station) to justify powered, elevator-equipped stations. I also believe cost of track is a sort of “holy grail” when it comes to PRT, because the “network effect” is everything. Anyway, there’s more in my upcoming post.