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Advanced Coupler Adding slack and damping

#31 User is offline   Genma Saotome 

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Posted 10 May 2019 - 09:03 AM

View Postcopperpen, on 10 May 2019 - 02:34 AM, said:

As the main part of the object by definition of its name is invisible, I don't think you would need a major offset.


How about the 25m gap I have between the track and the surface of the water? My point is not all routes are alike.

#32 User is offline   copperpen 

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Posted 10 May 2019 - 10:58 AM

As that part of the wag/model is invisible, what does it matter how big the gap is. I am not talking about putting a stonking great 86 foot boxcar complete with skin in midair, just a small cube with all sides alphaed out. While it is clear that not all routes are alike they all have one common denominator, a TDB. To my mind all that is needed is a shape that is far enough below the tdb level to avoid crash detection that can be placed and not collected.

#33 User is offline   Genma Saotome 

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Posted 10 May 2019 - 12:22 PM

Ahhh, I did not realize what you intended for the shape... nevermind!
:give_rose:

#34 User is offline   steamer_ctn 

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Posted 20 June 2019 - 01:57 PM

A working version for Advanced Coupler operation has been added to MG.

A demonstration activity has been created and is available from here.

The key parameters required to configure the advanced coupler are as follows:
ORTSTensionStiffness ( a b ) - coupler forces, where a = coupler force at end of Zone 2, and b = coupler force at end of Zone 3.
ORTSTensionR0 ( a b ) - coupler displacement distances, where a = zero length (adjusts distance between cars), and b = displacement distance of Zone 1.
ORTSTensionSlack ( a b ) - coupler displacement distances, where a = displacement distance of Zone 2, and b = displacement distance of Zone 3.
ORTSCompressionStiffness ( a b ) - coupler forces, where a = coupler force at end of Zone 2, and b = coupler force at end of Zone 3.
ORTSCompressionR0 ( a b ) - coupler displacement distances, where a = zero length (same as value above), and b = displacement distance of Zone 1.
ORTSCompressionSlack ( a b ) - coupler forces, where a = coupler force at end of Zone 2, and b = coupler force at end of Zone 3.

ORTSBreak ( a b ) - Coupler breaking force, where a = force at end of Zone 2, and b = force at end of Zone 3.
CouplingHasRigidConnection ( a ) - defines coupler as rigid (very small amount of slack), where 0 = flexible coupler, and 1 = rigid.

For more information on setting up Advanced Couplers see here.

#35 User is offline   Traindude 

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Posted 20 June 2019 - 08:30 PM

Something else to think about while we're rewriting the coupling code...

http://www.elvastowe...-front-coupler/

#36 User is offline   Lamplighter 

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Posted 07 July 2019 - 03:32 AM

Hello!
I tried this new feature.
I used the same two trains. One with advanced cuplers and the other with standard couplers.
I tried it on the simulator OR MG and standard OR.

Here's my code for advanced couplers:
Comment ( "Open Rails Advanced Couplers" )	
Coupling (
Type ( Chain ) 
Spring ( 
ORTSTensionStiffness ( 4e5N 2.64e7N )
ORTSTensionR0 ( 0cm 1.0cm )               
ORTSTensionSlack ( 0.5cm 1.5cm )           

ORTSCompressionStiffness ( 4e5N 2.64e7N ) 
ORTSCompressionR0 ( 0cm 1.0cm )     
ORTSCompressionSlack ( 0.5cm 1.5cm )   

ORTSBreak ( 8.5e5N 8.5e5N ) 
) 
CouplingHasRigidConnection ( 0 )
Velocity ( 0.01m/s ) 
)


I found out that the advanced couplers function partially. He can only tension, but no longer compression (with braking or without power and so on).
Here's an overview:

https://1iq.cz/img/C9a2k/66XPz.png

And here video (OR MG + Advanced Couplers):
https://youtu.be/ZmdmhDLkqXo

and video (OR MG + Standard Couplers):
https://youtu.be/vSNesJuoAZo

I'm not sure I'm doing something wrong.

#37 User is offline   steamer_ctn 

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Posted 07 July 2019 - 11:59 PM

View PostLamplighter, on 07 July 2019 - 03:32 AM, said:

I tried this new feature.
Thanks for the feedback.

Firstly a couple of comments.

This feature is still a WiP (work in progress) as the code is closely entwined with the basic code for train movement in OR, and I am still trying to integrate the features without breaking basic train movement.

View PostLamplighter, on 07 July 2019 - 03:32 AM, said:

I tried it on the simulator OR MG and standard OR.
The advanced coupler code has not presently been integrated into the mainstream (standard) OR program. So apart from comparing "standard" coupler features between the standard OR and OR MG, there is no value in looking at advanced couplers in standard OR.


View PostLamplighter, on 07 July 2019 - 03:32 AM, said:

I found out that the advanced couplers function partially. He can only tension, but no longer compression (with braking or without power and so on).
The activity demonstrating this feature shows one scenario where compression does happen, ie when traveling over an undulating section of track. Also reversing the train will cause the couplers to compress and the train to "bunch" up.

Compression may not automatically happen in all the scenarios suggested (eg braking, without power, etc). For example turning power off on a train may not cause compression if all the cars continue to move at the same speed with respect to each other, and slow down at the same rate. Similarly braking the train (using the train brake) may not cause compression either as the cars may not change speed relative to each other, and thus all slow down at the same rate.

I notice that you have appeared to brake the train with the locomotive brake only, and in this situation there may be some form of compression introduced to the train, and perhaps this is not showing up correctly at the moment.

So whilst compression is still present, it may not be fully functional for the advanced couplers in all valid instances where it makes sense to appear. Hopefully this will be corrected in the foreseeable future with a further patch.
You may also wish to review your R0 and Slack statements as the values do not appear to "increment" correctly across the various zone boundaries for the coupler.

Thanks again for the feedback.

#38 User is offline   darwins 

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Posted 08 July 2019 - 07:35 AM

Here is an interesting thought. Not really on the technical side, but on the practical. Just as dual braked vehicles were common on UK so were vehicles with two types of coupling for many years.

I refer of course to passenger carriages ( LNER / SR / BR ) with Pullman gangways and buckeye (knuckle) couplers. Carriages were joined within sets (carriage to carriage) by knuckle couplers with the Pullman gangways providing a part of the required strength. The couplers were drop head type with a draw hook underneath. Such rakes were always coupled to locomotives (and to vehicles without Pullman gangways) by dropping the knuckle, extending the side buffers and using the locomotive (screw) coupling.

Presuming that the two types of coupler would have different properties, which one would the modeller choose to use in an OpenRails wag file?

#39 User is offline   Lamplighter 

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Posted 08 July 2019 - 12:45 PM

View Poststeamer_ctn, on 07 July 2019 - 11:59 PM, said:

Compression may not automatically happen in all the scenarios suggested (eg braking, without power, etc). For example turning power off on a train may not cause compression if all the cars continue to move at the same speed with respect to each other, and slow down at the same rate. Similarly braking the train (using the train brake) may not cause compression either as the cars may not change speed relative to each other, and thus all slow down at the same rate.

I notice that you have appeared to brake the train with the locomotive brake only, and in this situation there may be some form of compression introduced to the train, and perhaps this is not showing up correctly at the moment.


I brake the locomotive therefore to point out on inertia forces.
But the HUD (and display) only shows a "pull". Even if the train stops.

Thank you for the explanation and I wish you much success to complete this feature.

#40 User is offline   Lamplighter 

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Posted 09 July 2019 - 12:13 AM

I would add an my opinion.
My English is not worth anything. I'll try to describe it best:

Longitudinal movements occur whenever the tensile force changes. Change force tensile occurs when: Descent and ascent railway track, power unit acceleration and deceleration, etc.
Pulling and pushing devices (eg couplings and buffers in Europe) or automatic couplings (eg in the USA or Russia) eliminate these movements.
When driving, there is always a longitudinal movement of the vehicle within the entire train.
How much coupling springiness allows (plus in Europe with the springiness of buffers).

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