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Why no decent scale models of PRT using off the shelf robots? (Izmir Institute of Technology PRT Demostration project)

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Tim J.

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Aug 1, 2013, 11:47:14 PM8/1/13
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Hello,

I came across the Izmir Institute of Technology PRT Demostration project (https://sites.google.com/site/ceng314prt/). When I search YouTube there are plenty of examples of impressive, simple bots (Pololu 3pi Line Maze Solving Robot, http://youtu.be/mJV-KDqHgDQ which sells for US$100 fully  assembled.)   There are very simple line follower bots.  But if you search for "PRT scale model" in YouTube the results are, politely, less than impressive.  (The film of the Aerospace Corp. model, from the 1970s(!!), are better than anything else.)

After this I wondered to myself why no one has created a decent PRT scale model with a dozen or so small bots running at high speed in a line drawn network using some of these off the shelf bots?  I would have thought some of robot aficionados would take it on as a challenge given they wouldn't have to start from scratch as there are so many algorithms and concepts in the public domain.

I found some work on other PRT models (http://www.autoroadvehicles.com/downloads/atra-2013-01-13-control-system-bob-johnson-3.pptx) but it was just one vehicle.  The discussion of scale model I have seen in this forum from last year seemed to focus on what scale it should be or on recreating the motion control system for one vehicle (https://groups.google.com/forum/#!topicsearchin/transport-innovators/Skytraxprt/transport-innovators/6DDSL1S6C0M).  

I would have thought the real challenge is the issue of continuous communication between the vehicles and the line side controllers and a central "dispatch" controller.  I realise that this is quite complicated to implement so maybe I am expecting too much.

Regards,
Tim
DISCLAIMER: I'm a curious (and sceptical) observer of PRT.

Dennis Manning

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Aug 2, 2013, 12:06:49 AM8/2/13
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Tim J.
 
Did you see any information on the Skyweb Express ( www.skywebexpress.com ) 20 vehicle table top PRT scale model. They might be willing to talk about the challenges of building a PRT scale model.
 
Den
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Tim J.

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Aug 2, 2013, 12:35:30 AM8/2/13
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Hi Den,

Yes, I had seen their video but the vehicles just queue behind one another then advance to the head of the queue and then move to the next queue. The track they have allows for more complex operation than that.  I can only assume that given they have posted only that vision on-line then that was the best they could achieve.

I suppose what I was expecting is something more closely approximating what exists in all the fancy CGI simulations - merge, de-merge, off-line stations, vehicles bypassing stations.


On Friday, 2 August 2013 14:06:49 UTC+10, Dennis Manning wrote:
Tim J.
 
Did you see any information on the Skyweb Express ( www.skywebexpress.com ) 20 vehicle table top PRT scale model. They might be willing to talk about the challenges of building a PRT scale model.
 
Den
Sent: Thursday, August 01, 2013 8:47 PM
Subject: [t-i] Why no decent scale models of PRT using off the shelf robots? (Izmir Institute of Technology PRT Demostration project)
Hello,

I came across the Izmir Institute of Technology PRT Demostration project (https://sites.google.com/site/ceng314prt/). When I search YouTube there are plenty of examples of impressive, simple bots (Pololu 3pi Line Maze Solving Robot, http://youtu.be/mJV-KDqHgDQ which sells for US$100 fully  assembled.)   There are very simple line follower bots.  But if you search for "PRT scale model" in YouTube the results are, politely, less than impressive.  (The film of the Aerospace Corp. model, from the 1970s(!!), are better than anything else.)

After this I wondered to myself why no one has created a decent PRT scale model with a dozen or so small bots running at high speed in a line drawn network using some of these off the shelf bots?  I would have thought some of robot aficionados would take it on as a challenge given they wouldn't have to start from scratch as there are so many algorithms and concepts in the public domain.
 
I found some work on other PRT models (http://www.autoroadvehicles.com/downloads/atra-2013-01-13-control-system-bob-johnson-3.pptx) but it was just one vehicle.  The discussion of scale model I have seen in this forum from last year seemed to focus on what scale it should be or on recreating the motion control system for one vehicle (https://groups.google.com/forum/#!topicsearchin/transport-innovators/Skytraxprt/transport-innovators/6DDSL1S6C0M).  

I would have thought the real challenge is the issue of continuous communication between the vehicles and the line side controllers and a central "dispatch" controller.  I realise that this is quite complicated to implement so maybe I am expecting too much.

Regards,
Tim
DISCLAIMER: I'm a curious (and sceptical) observer of PRT.

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Jack Slade

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Aug 2, 2013, 12:47:10 AM8/2/13
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You can look at my operating bench model at  SKYTRAXPRT  on youtube.  If you can ignore my crappy handiwork( I built it with wood)  and actually look at how it operates,  I think it shows how one very simple station would work.  Only with 5 cars,  because I did not have the space for a complete system.
 
Jack Slade

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Dennis Manning

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Aug 2, 2013, 12:52:25 AM8/2/13
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That doesn’t sound like PRT scale model I’ve seen. Try:
 
 
Scroll down to  Alpha System (page 6)
 
Where is the on-line post you mention. I don’t believe I’ve ever seen it?
 
Dennis
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Rick D

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Aug 2, 2013, 12:56:18 AM8/2/13
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Tim,

Might it not be easier and more informative to build accurate simulations of a large system?

Once the vehicle, track side, and central control systems are validated, a large scale prototype to validate key components and functions.

Isn't this what Vectus did?



From: Tim J. <tje...@gmail.com>
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Sent: Thursday, August 1, 2013 11:47:14 PM
Subject: [t-i] Why no decent scale models of PRT using off the shelf robots? (Izmir Institute of Technology PRT Demostration project)

Kirston Henderson

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Aug 2, 2013, 1:00:48 AM8/2/13
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It is often less costly to just build the full-size system.

eph

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Aug 2, 2013, 1:04:20 AM8/2/13
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This approach works well if funding is available.  Make CAD drawings, computer simulations and build the design.  If you are trying to persuade investors on a limited budget, I think a working model instead of a video montage (real or CG) gets more respect.  Urbanaut built a scale model and got funding to build in Korea.  The fate of the system is unfortunate, but does not necessarily reflect the process.  I think it's harder to fake a working scale model.


F.

Kirston Henderson

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Aug 2, 2013, 1:20:43 AM8/2/13
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That is precisely the reason that MegaRail® designed, built, and
tested a full-size MicroWay™ mass transit passenger car working demo
model. With it, we were to fully test the critical vehicle steering
and switching with the real hardware, including the essential portion
of a short test guideway. A single 49-ft section and full sized
elevated guideway was built to verify guideway strength and deflection
and the emergency escape walkway feature.

Kirston Henderso
MegaRail® Transportation Systems, Inc.

Tim J.

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Aug 2, 2013, 2:27:18 AM8/2/13
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Hi Dennis,  

It's on their website (on the link you sent me under "Technology")  see:  http://www.taxi2000.com/images/movies/AlphaVehicles.wmv




On Friday, 2 August 2013 14:52:25 UTC+10, Dennis Manning wrote:
That doesn’t sound like PRT scale model I’ve seen. Try:
 
 
Scroll down to  Alpha System (page 6)
 
Where is the on-line post you mention. I don’t believe I’ve ever seen it?
 
Dennis

Tim J.

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Aug 2, 2013, 2:50:31 AM8/2/13
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By simulation I take it you mean "computer simulation".    What I was expecting was a test network with a fair number of vehicles (10+) with all that MECHATRONIC complexities involved in integrating the electrical, electronic and mechanical systems.  I don't think a full scale prototype would be cheaper than small robots for this.

I'm not doubting the necessity for full scale prototypes but if there is only single or a couple of vehicles this doesn't really test resolve the functioning of the SYSTEM.  My original curiosity was stirred by the fact that as the full potential of PRT is supposed to emerge only when there is a number of vehicles on a non-simple network then why are their no decent scale models of such operation.   It seemed to me superficially that there is not a technical barrier to constructing one.

Perhaps the Skyweb Express model is more sophisticated than their own video shows (that's what the description in their documents say p.6 http://faculty.washington.edu/jbs/itrans/SWE%20marketing%20intro.pdf)  but I would be interested to see it.  As it stands I think their video is under whelming.  (There are worse on YouTube from JPods).

Regards,
Tim

Rick D

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Aug 2, 2013, 9:32:07 AM8/2/13
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Tim,

Certainly a VERY underwhelming video at first look. I'd agree that it looks jerky and seems to be vehicles going from one stopped line to another.

The jerkiness would be why I would steer away from miniature models. A computer simulation setup with separate computers simulating different aspects of the system would fully validate the control systems on as big a system as the computer memory and performance can handle.

I've seen transit system control centers, automated and manual train operation, set up and fully operational while the track is still being laid. The control room equipment simply communicated with computers simulating the movement of trains and track and signals. This capability is almost vital, because even once the system is fully operational and all hardware is installed and trains running, the simulation system provides a means to train control centre personnel by simulating accidents, failures, and other various incidents.

For automated systems, one computer running vehicle control software and another running track/system interface validates vehicle  system control. And again, you can validate failures, incidents, and emergencies for the control software that would be difficult to duplicate in real life.

For the hardware validation, go as big as the budget can allow (Vectus, Ultra, or MegaRail as example). All you need is a divergence, a merge point, a high speed section, a few curves, a station. Something like this: http://www.aar.com/tracks.php (but in PRT scale).

With that covered, regulators can validate controls and hardware, and clients know that the systems works, is reliable (run a 10,000 mile simulation on the test track), and is fully scalable.
 


Sent: Friday, August 2, 2013 2:27:18 AM

Subject: Re: [t-i] Why no decent scale models of PRT using off the shelf robots? (Izmir Institute of Technology PRT Demostration project)

Rick D

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Aug 2, 2013, 9:40:43 AM8/2/13
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Tim,

I failed to expand on the scale model and simulation a little in my last post and so will continue here.

"What I was expecting was a test network with a fair number of vehicles (10+) with all that MECHATRONIC complexities involved in integrating the electrical, electronic and mechanical systems."

The problem is that the scale model of the vehicle shows you virtually nothing about the reliability or operation of the final vehicle.

The skyweb video isn't so bad once you understand that the lines are actually stations. But getting the little vehicles to behave correctly and the "MECHATRONIC complexities involved in integrating the electrical, electronic and mechanical systems" is almost  as complex as the full scale version but is almost immaterial to the final full scale prototype.

For example, instead of spending all that time on little vehicles, there could be one computer simulating all of the cars, track, signalling, and other system components, and another connected by WiFi simulating a single vehicle.

As discrete system electronics are designed/adopted they can be integrated in their final form into the simulation. That is use the real communications hardware, propulsion controllers, power supplies, etcetera.

Meanwhile the full scale prototype validates the physical performance of the vehicle that corresponds to the outputs in the simulator.


Sent: Friday, August 2, 2013 2:50:31 AM
Subject: Re: [t-i] Why no decent scale models of PRT using off the shelf robots? (Izmir Institute of Technology PRT Demostration project)

Dennis Manning

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Aug 2, 2013, 12:06:08 PM8/2/13
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Tim J:
 
You wrote: Yes, I had seen their video but the vehicles just queue behind one another then advance to the head of the queue and then move to the next queue. The track they have allows for more complex operation than that. I can only assume that given they have posted only that vision on-line then that was the best they could achieve.
 
That is what confused me. The video isn’t very good. The queuing that takes place is on the off-line tracks only. So if you look closely you will see that the model shows merge and demerge. The on-line track portions in the model are deceptively short.
 
I agree there is room for much better PRT scale models. I think it’s just the normal barriers – time, money, the right people to do the work,  etc.
 
Dennis
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eph

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Aug 2, 2013, 1:09:22 PM8/2/13
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What would be needed is a "reality check" third party simulator that took a vehicle model with all it's characteristics and all the output data from the proprietary computer simulation and just verified that all characteristics, physics, etc.  all "worked".  Then the computer simulation would be on a similar footing with a scale model.

Building a full scale prototype is easier in some ways because COTS either exist or they don't so the design matches reality which is not the case with small scale models.  The big expense is the infrastructure needed to test the prototype at speed and in merges and diverges.  Road based vehicles have an advantage there since they can use existing infrastructure to a great extent.

I'm a bit on the fence on this one.  Small scale also has portability whereas full scale requires a major installation.


http://www.urbanaut.com/Basic%20Principal%20and%20Technology%204.htm




F.

Tim Joy

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Aug 2, 2013, 11:47:17 PM8/2/13
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Do any of the simulations include a reality check of the kind you propose?  That sounds eminently logical to me.

I read in the Aerospace Corp. review of the San Jose proposal they were concerned none of the vendors mentioned potential problems with wireless communication.


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Jack Slade

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Aug 3, 2013, 3:18:46 AM8/3/13
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Only a fool would plan PRT safety using wireless data in a situation where fiber-optics can easily be used.  Radio can be interferred with...by faulty local equipment,  by thunderstorms,  or by sabotage.   I don't have such a high opinion of Aerospace as I used to have on the recommendation of people who knew their reputation 40 years ago.  Too many people have retired or died,  and their replacements just use their heads to hang hats on. 
 
Jack Slade

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Subject: Re: [t-i] Why no decent scale models of PRT using off the shelf robots? (Izmir Institute of Technology PRT Demostration project)
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Tim J.

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Aug 3, 2013, 6:42:50 AM8/3/13
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I don't mind the jerkiness (although there are ways of simulating mass with the motor controllers such as better throttles on model railways ["model railroads" to you Americans :-)])  

I just don't understand the point of creating a fleet of vehicles, running all sorts of test and then showing us ONLY that.

My initial curiosity about this question was prompted by the following paragraph from the blog http://openprtspecs.blogspot.com.au/2013/02/railbotics.html
Ever see the video of that old tape by Aerospace Corp?  That is more than a good primer on PRT. That model is one very cool toy…There are still thousands of model railroad enthusiasts out there who get great satisfaction building similar stuff, not to mention robot buffs.  Could model “railbots” (not to be confused with the game) ever gain a following?  After all, a working model of the SMART PRT platform would certainly be equally fun to watch and vehicle avoidance and routing strategies would offer programmers something truly challenging to chew on.

I remain to be convinced about PRT in widespread network but I thought this was a fair point.  I find all the computer simulations like watching "Avatar"; anything is possible in CGI.

Tim

Eric Johnson

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Aug 3, 2013, 11:54:55 AM8/3/13
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SkyWeb Express only has this video posted with a small clip of their models merging. Is there another video of their model setup?
Eric

Dennis Manning

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Aug 3, 2013, 4:59:50 PM8/3/13
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What is your reservation about PRT in a widespread network? If one can have a large scale baggage handling network what problems does PRT have that make scalability a show stopper?
 
Dennis
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Tim J.

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Aug 4, 2013, 12:22:39 AM8/4/13
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I don't think large scale baggage handling is equivalent to a "widescale network" as it exists in a controlled, sympathetic environment and solve the  problem of the speed of disembarking by throwing its "passenger" off down a slide without stopping.  It's a limited analogue.

I should have added the extra condition of widescale URBAN networks.   to justify their capital cost would have to operate at, or near, their theoretical capacity.    If the origin/destination load is not balanced, it will need to overcome the speed of loading and unloading (larger stations?) and for a system of 100s of vehicles all will need to operate faultlessly.

Back on the issue of airport baggage handling I was surprised to read about the failed Denver Airport system that they were BOTH a.warned at the start that it was impossible to achieve (both in the time frame or at all at the time) AND b. that the tug & trolley system could NOT support the requirements.  The first proved to be true and the second to be false.  

I read some of the Aerospace Corp. review of San Jose and it seemed obvious that the headway of 6 seconds was excessively conservative but I assume this was the best the vendors who replied to the RFI reported to them.  Even at half that (still conservative) a network should be able to handle the projected 2030 demand.  In that kind of application I would imagine it might be superior.   I haven't analysed the alternatives but I think PRT would have to prove itself in just such an installation.

Perhaps the Amritsar project will put all of this to the test but I have read that to overcome capacity constraints they plan to have extra guideways.

I suppose part of my reason for posing the question on scale models in this forum in the first place there seemed to be an obvious gap between the (hyperbolic?) claims and the `facts on the ground'.

More broadly I always bear in mind that there are significant social and political problems in all forms of transportation for which there are no technological solutions.

I'm sorry if I have gone on so lone but I've tried to give a complete answer.   I look forward to any replies.

Regards,
Tim
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Jack Slade

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Aug 4, 2013, 4:12:06 AM8/4/13
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Tim,  I want to tackle your second paragraph only.
 
Not so.  When cities build a streetcar or subway line they never expect to get a cent of capital costs back.  In addition,  they know they will always have to subsidize it annually,  and over 20 years the subsidy will be greater than the capital costs.
 
If they spend an equal amount of money building PRT,  even light to moderate traffic will break even at the farebox.  When nobody moves,  the system costs nothing...no drivers,  no energy, and users should still be paying less than existing modes charge.  I have calculated $0.15 per mile will produce profits.
 
Jack Slade
 

From: Tim J. <tje...@gmail.com>
To: "transport-...@googlegroups.com" <transport-...@googlegroups.com>
Sent: Sunday, August 4, 2013 12:22:39 AM
Subject: Re: [t-i] Why no decent scale models of PRT using off the shelf robots? (Izmir Institute of Technology PRT Demostration project)
From: Tim J. <tje...@gmail.com>
To: transport-...@googlegroups.com
Sent: Friday, August 2, 2013 2:27:18 AM
Subject: Re: [t-i] Why no decent scale models of PRT using off the shelf robots? (Izmir Institute of Technology PRT Demostration project)
 
Hi Dennis,  
 
It's on their website (on the link you sent me under "Technology")  see:  http://www.skywebexpress.com/
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Tim J.

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Aug 4, 2013, 7:52:40 AM8/4/13
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Hi Jack,

Is that $ 0.15 per passenger mile or per vehicle mile?  
If its $0.15 per passenger mile what is the load factor?  
This would cover all operating costs including power, maintenance, cleaning etc.?

Most public transport doesn't pay for itself directly but there is a positive economic return.  In most cases the government subsidy is realised in the increased value of residential and especially commercial real estate along the route.  The alternative of buses or cars & car parks would be unsatisfactory.   The systems I was thinking about have to carry the crush-load of morning and evening peak,  The waste in the off-peak is only justifiable by their peak capacity.

In my thought experiment if these types of systems were replaced with widespread PRT I see the constraints on PRT at peak times would tend make it inoperable, particularly with the asymmetry of travel .  Is this fair?  Are there circumstances where light-rail is preferable?

If you're right we should see PRT systems spring up in the modernising cities of Asia, South America, Africa, the Middle East and even the conversion of existing public transport to PRT.

Do you think the Amritsar plan will be a test of the paradigm?  They are quoting figures of up to 100,000 passengers per day.

Just to tie this back to the topic of the thread: the capacity issue is why I was curious to see a model simulating a network running at its limit.

Regards,
Tim

Eric Johnson

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Aug 4, 2013, 10:56:47 AM8/4/13
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Tim,
Let me take a crack at what you say and ask. Long posts are not a problem as we are here to discuss innovation transportation.

While there are differences between PRT and baggage systems, both are involved in getting something from multiple origins to multiple destinations in a complex layout. These baggage systems prove that we can write software that handles this complexity well and quickly and that we can build these complex networks. I see many basic PRT functions being verified by these baggage systems.

PRT networks provide better coveraged at lower cost vs any other transit system. If we assume inclusive system costs are $15 Million per mile, operating & maintenance costs of 4%, debt service costs are 5% of the capital costs, ticket price of $2.50 per rider, then we need 1538 riders per mile to break even. In the Phoenix area, that would mean a ~10% trip share which seems very doable considering 2/3 of the folks would be within a 5 minute walk of a station in the covered area. I've attached an Excel spreadsheet that you can play with and see what your numbers would do to ridership.

Capacity is an interesting discussion since your point applies to every transportation type, yet few people serious quibble when the new road expansion is swamped when it opens up. The same is possible for PRT and the nice thing is it's fairly easy for PRT to expand around those choke points or increase guideway capacity by reduced headways, platooning, increasing per pod ridership numbers, etc. If PRT capacity is maxed out, it should be pretty easy to get new financing to expand.

Denver was not an impossible problem. It could have been fixed with good leadership & time to debug the system. The system didn't work because of poor decisions made at multiple points in planning, design, and construction. Then since it wasn't working airport leadership took the easy way out by blaming the system instead of fixing it.

Aerospace went with 6 second headways even though we have plenty of systems that have proved 3 seconds or less are safe and reliable (Cabintaxi, Morgantown, Ultra, etc). Plus they never considered the idea that system operation after 30 years would confirm lower headways as being realistic and safe too.

Amritsar has steady heavy traffic all day long for some 20 hours a day. There system can handle 50,000 people per day per direction since they are looking to pack each pod with 6 people. If we assume they average 5 people per pod and 6 second headways that's 3000 people per hour per direction or some 60,000 people per day. Station capacity & design seems to be the main issue to handle that many people.

We base our claims on what PRT can do on simple math (headway * pax per pod, station throughput, speeds, etc) and that we've had several PRT test systems that have separately proven the concepts with different software & hardware. Guideway construction, vehicle design & construction, station construction, vehicle communications, etc are well known. We can use existing software or write new programs to meet our needs. The only thing needed to make a new PRT functional is a test track program to verify integration & operations.

These are just some of the reasons behind why I'm excited about what PRT can do.
Eric


On Saturday, August 3, 2013 9:22:39 PM UTC-7, Tim J. wrote:
I don't think large scale baggage handling is equivalent to a "widescale network" as it exists in a controlled, sympathetic environment and solve the  problem of the speed of disembarking by throwing its "passenger" off down a slide without stopping.  It's a limited analogue.

I should have added the extra condition of widescale URBAN networks.   to justify their capital cost would have to operate at, or near, their theoretical capacity.    If the origin/destination load is not balanced, it will need to overcome the speed of loading and unloading (larger stations?) and for a system of 100s of vehicles all will need to operate faultlessly.

Back on the issue of airport baggage handling I was surprised to read about the failed Denver Airport system that they were BOTH a.warned at the start that it was impossible to achieve (both in the time frame or at all at the time) AND b. that the tug & trolley system could NOT support the requirements.  The first proved to be true and the second to be false.  

I read some of the Aerospace Corp. review of San Jose and it seemed obvious that the headway of 6 seconds was excessively conservative but I assume this was the best the vendors who replied to the RFI reported to them.  Even at half that (still conservative) a network should be able to handle the projected 2030 demand.  In that kind of application I would imagine it might be superior.   I haven't analysed the alternatives but I think PRT would have to prove itself in just such an installation.

Perhaps the Amritsar project will put all of this to the test but I have read that to overcome capacity constraints they plan to have extra guideways.

I suppose part of my reason for posing the question on scale models in this forum in the first place there seemed to be an obvious gap between the (hyperbolic?) claims and the `facts on the ground'.

More broadly I always bear in mind that there are significant social and political problems in all forms of transportation for which there are no technological solutions.

I'm sorry if I have gone on so long but I've tried to give a complete answer.   I look forward to any replies.

Regards,
Tim
PRT Estimator4 130610.xls

Dennis Manning

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Aug 4, 2013, 12:26:19 PM8/4/13
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Eric and Jack:
 
Pretty good responses to Tim J’s misgivings about PRT being able to handle widespread urban deployments. Jay: I’d like to add just a short comment. You stated: I should have added the extra condition of widescale URBAN networks. to justify their capital cost would have to operate at, or near, their theoretical capacity.
 
I think you make a series of unwarranted assumptions. To begin with there is wide range of yet unproven capital costs for PRT. Second there is also a wide range of what constitutes theoretical capacity which includes vehicle speed, size, and headway. Then there is a large difference of opinion on what the ridership will be on any given system. However, if you make some basic and I think reasonable assumptions as to cost, capacity. and demand as Eric has done you will find PRT will do nicely at large urban scale. It’s easy to be be pessimistic and attribute high cost, low capacity numbers to PRT to argue it won’t work, I suggest you look over the information on these parameters. Perhaps it will alleviate some of your misgivings, and at this point I’d ask what you are basing your thinking on as to cost, capacity, and demand?
 
Dennis
 
Sent: Sunday, August 04, 2013 7:56 AM
Subject: Re: [t-i] Why no decent scale models of PRT using off the shelf robots? (Izmir Institute of Technology PRT Demostration project)
 
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Jack Slade

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Aug 4, 2013, 1:30:13 PM8/4/13
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Calculations were for vehicle miles.  However,  when only the first line is built I can forsee the necessity to move 3 people per vehicle during rush hour.  We only get densities like this when we force people to travel from a couple miles each side of the line to use the system.  When the network gets finifhed walking distances shorten,  and line densities of 30,000 per mile will be unherd of,  just a fading bad memory.  I don't expect line density to ever exceed 5,000 except perhaps at special events such as ballgames,  rallies, and some organized celebrations after a full network is in operation.

Eric Johnson

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Aug 4, 2013, 5:22:57 PM8/4/13
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Here is a video about baggage handling at Amsterdam's Schiphol Airport. It shows conveyor belt, a PRT style system, and storage operations in a 13 minute video. 
Eric


On Saturday, August 3, 2013 9:22:39 PM UTC-7, Tim J. wrote:

Jack Slade

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Aug 4, 2013, 5:58:31 PM8/4/13
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Good video.  Did you notice the size of those baggage-transfer containers.  They are bigger than my PRT cars,  and move straight into the cargo hold...by conveyor.  Only last week somebody tried to laugh at my PRT conveyor system for moving people.  Ha Ha.
 
Jack Slade

From: Eric Johnson <itse...@gmail.com>
To: transport-...@googlegroups.com
Sent: Sunday, August 4, 2013 5:22:57 PM
Subject: Re: [t-i] Why no decent scale models of PRT using off the shelf robots? (Izmir Institute of Technology PRT Demostration project)
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Tim Joy

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Aug 4, 2013, 11:56:47 PM8/4/13
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Hi Eric,

 

Is it right to say “Amritsar has steady heavy traffic all day long for some 20 hours a day”?  Surely that would be a unique situation, unprecedented in fact.  (I don’t know much about the Golden Temple or Sikh rituals so I am willing to concede that it may be the case).

 

Also you say “Station capacity & design seems to be the main issue to handle that many people.“  Isn’t that the million dollar question for PRT?  The real constraint is in the stations.  (Not a unique problem to PRT).  I think I read somewhere that the Amritsar plan is to duplicate the guideways in some areas to add capacity.

 

If you say “The only thing needed to make a new PRT functional is a test track program to verify integration & operations“ does that mean CabinTaxi, ULTra and Vectus have NOT shown PRT is functional?  (Excuse my ignorance but I am guessing you have a different design).

 

You said:

Amritsar has steady heavy traffic all day long for some 20 hours a day. There system can handle 50,000 people per day per direction since they are looking to pack each pod with 6 people. If we assume they average 5 people per pod and 6 second headways that's 3000 people per hour per direction or some 60,000 people per day. Station capacity & design seems to be the main issue to handle that many people.

 

We base our claims on what PRT can do on simple math (headway * pax per pod, station throughput, speeds, etc) and that we've had several PRT test systems that have separately proven the concepts with different software & hardware. Guideway construction, vehicle design & construction, station construction, vehicle communications, etc are well known. We can use existing software or write new programs to meet our needs. The only thing needed to make a new PRT functional is a test track program to verify integration & operations.

 

 

 

 

From: transport-...@googlegroups.com [mailto:transport-...@googlegroups.com] On Behalf Of Eric Johnson
Sent: Monday, August 05, 2013 12:57 AM
To: transport-...@googlegroups.com
Subject: Re: [t-i] Why no decent scale models of PRT using off the shelf robots? (Izmir Institute of Technology PRT Demostration project)

 

Tim,

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Tim Joy

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Aug 5, 2013, 2:42:57 AM8/5/13
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Hi Eric,

 

I’ll have to study your spreadsheet to get a better feel for it.  It’s impressive with a lot of information.

 

After an initial view the first thing that comes to mind is I would have thought elevated stations would cost more than your calculations would indicate.  Have you compared these costs with any similar structures?

 

Tim

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From: transport-...@googlegroups.com [mailto:transport-...@googlegroups.com] On Behalf Of Eric Johnson


Sent: Monday, August 05, 2013 12:57 AM
To: transport-...@googlegroups.com

Subject: Re: [t-i] Why no decent scale models of PRT using off the shelf robots? (Izmir Institute of Technology PRT Demostration project)

 

Tim,

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