Issue with shaft/gear linkages

BillM
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Issue with shaft/gear linkages

Post by BillM »

Art

I've been pushing the boundaries of what should be possible with Ticker.exe. I'm running version 2.03B of Ticker. I started a work around for being able to create a library of gears for a chronometer sim experiment using mtass files and ran into issues where my model would simply lock up...I'll tell you about the technique later. It took me a while to come up with a simple gear set example to show the issue.

I've possibly isolated a shaft naming / gear linkage issue. I tried zipping the project file but unfortunately the zipped file is is slightly greater than 2MiB.

I'll describe the issue, perhaps it will behave differently on your system. (I've created jpeg snapshots of gear settings to illustrate what I created and included them in the attached zip file).

I create a spur gear set with mod 0.3349, 1mm shaft, 1.1mm collars, 0.5mm collar depths 120T wheel, 18T pinion. When added to the workbench the wheel is mounted on Shaft, the pinion is mounted on Shaft[2]. I expected this numbering system. However both the Wheel and its pinion are locked simply to Shaft. The pinion should have been locked to Shaft[2].

I then create a planetary set, mod .2623, face width 0.5mm, shaft 1mm, collars same as spur gear set 144T wheel, 16T pinion.
I add the wheel to the shaft of the pinion of the spur gear set, and then add the planetary pinion to the planetary wheel. The planetary pinion's shaft is Shaft[3] as expected. However both the planetary wheel and pinion are locked to Shaft rather than their proper shafts.

The the model will lock up after a while. At first I would set a low rpm motor on the spur gear and things would look like the sim was working. If I turn off the spur motor and then enable a motor on a different gear or pinion the sim model would struggle to move at all. I assume this is because of the linkages on gears that conflict in CW, CCW rotations when all linked to the same shaft.

Bill Michael
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TickerProject-LinkageErrors.zip
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ArtF
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Re: Issue with shaft/gear linkages

Post by ArtF »

Thanks Bill:

I will investigate the issue. I have made a few changes since last release, Ill see what it does here. Im close to another release
shortly so if I can replicate this, Ill fix it up.

Art
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Re: Issue with shaft/gear linkages

Post by ArtF »

Bill:

I dont think its a naming issue per say. While non gears or imported objects list their shafts by name, the gears only have the word
"Shaft" as their shaft name no matter the real shaft. This was done as gears at the time could only have one shaft. I will redo this though,
as now that imports from Vexx are so easy, this is an issue. I will have the system name the shafts on all objects to more easily see
the issues that may exist.
The next version is close to ready with Ellipticals being available, as well as elliptical planetaries. I will make the shaft naming changes
before release. I have found a few other bugs that need to be addressed as well. I have seen some issues with MTass files of some types not
changing their linkages properly and am looking into that as well. Thanks for the report, I suspect the MTass error is your true culprit.
Perhaps under global properties I should show a list of objects constrained to an object. That may make it clearer.
In the end I need to make a way to make your own constraint joint, such as when designing a planetary where the placed gear needs to
be joined to an existing ring gear and the inside as well at the same time. Constraints are easier than in most sim's , as each object can be
constrained to any other object as a binary IS or ISNT connected. The details of the constraint, prismatic, distance, orientation, degrees of freedom
and such are all automatic and need not be worried about, so it may be time to add the "Constrain this Object to That Object" button.

Work continues.. hope your spring is sprung..

Art
BillM
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Re: Issue with shaft/gear linkages

Post by BillM »

Art,

I think I'll wait for the next version. I reloaded version 2.03B, recreated the gear example as described earlier but could not re-create the problem.
Perhaps something had gotten corrupted in the version 203B that I had been using.

The gears in my example were created directly from the Spur Gear and Planetary Gear 3D model tools. I have experimented with tass files (my balance & crown gear).

I've also experimented with creating gear pairs and saving them as mtass and also creating a single gear mtass file. This experimenting was to see if gears in mtass files would behave as placeable gears and how to use them.

The tass and mtass files behave differently during Asset import. Tass assets can be placed anywhere on the workbench. When placed on a shaft it can be locked to the name of the shaft, e.g. Shaft[2] (if I rename the shaft the asset reflects the name change).

With an mtass gear pair, I load it off to the side on the workbench. Using the "copy selected" command, add the copied gear to either an existing shaft or to a gear (providing the gears have the same module). This copy technique seems to work but perhaps possibly messed up the sim model I had been building.

Bill
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Re: Issue with shaft/gear linkages

Post by ArtF »

Bill:

New version almost ready. A weakness to the importing is that constraints can't be done by the user ( as of yet), its all automatic and so I may have
missed something in some algorithm that causes that occasional glitch. This version has many fixes , and added helpers such as asking if you'd like a shaft removed it its no longer used.
Also, if placing on a shaft , and switching to another placement the shaft that was elongated for selection will automatically shrink
and recalculate again. The ellipticals are new and from Gearotic with certain changes to allow full 3d motions.

We'll see if that helps, should be out within a couple days.

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Re: Issue with shaft/gear linkages

Post by ArtF »

Bill:

Version 2.04Beta is now online. I will be making a video to show the elliptical operations, but I figured Id let you know it is now
online so you can play and see if it fixes any of your issues. You can make planetary ring ellipticals, but cannot use sun/planet
full planetaries with the ellipticals as I'll explain in the video. It has to do with the formulation I use for ellipticals which is not a
typical formula. I may add a functional gear design later on with noncircular planetary capability for that kind of requirement.

Art
BillM
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Re: Issue with shaft/gear linkages

Post by BillM »

Art

I've downloaded v2004B. I managed to crash Ticker. The attached zip file contains two versions of a project where I used the built in capability to place a bevel wheel/pinion. I attached a 100RPM motor to the pinion.

A-AutoPlaceBevels Runs fairly well. I attached the Ticker-Success log file for the successful run/exit

I then fused the shaft of the wheel to the workbench, tried to run the simulation...Ticker crashed.
This is saved as A-AutoPlaceBevels02 & Ticker-Crash log file is the corresponding log file.

Some Observations which I've seen in previous versions:

There are two shafts: Shaft & Shaft[2]. The Wheel is locked to Shaft, the Pinion is locked to Shaft[2] as I expected.

If I first select the pinion and then the wheel and Translate On Plane changes in X moves the pinion along the Z axis, Y moves it in Y, Z moves the pinion along the X axis is this normal?

Bill
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Re: Issue with shaft/gear linkages

Post by ArtF »

Hi Bill:

I think you forgot to attach the files, ..

>>If I first select the pinion and then the wheel and Translate On Plane changes in X moves the pinion along the Z axis, Y moves it in Y, Z moves the pinion along the X axis is this normal?

The translation directions are localized. Z means up or down a shaft no matter the orientation, X,Y are orthogonal to the Z axis. There is
no "right" or "wrong" to this axis system, I'm not sure it'd be better to have it locked permanently to the actual world XXZ axis or define it as Left,Right and Z down on shaft as a paradigm.. Im open to thoughts on the subject. Interface in this type of program is truly difficult to determine as to what's more intuitive or easy. I often try many things just to see how they feel..

Repost the files and Ill let you know what's crashing..and stop it from happening again.

Art
BillM
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Re: Issue with shaft/gear linkages

Post by BillM »

Art

I'll give it a try again. Hopefully the file will stay attached this time.

I don't know if there is any good way to deal with coordinate systems when dealing with rotational vector transform matrices. I'm a bit familiar with inertial systems dealing with roll, pitch and yaw and having to know the gimbal order of operations and also having to define if it's a right handed or left-handed coordinate system.

Bill Michael
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V204B bevel crash.zip
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Re: Issue with shaft/gear linkages

Post by ArtF »

Thanks Bill:

Ill let you know what I find.

Art
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Re: Issue with shaft/gear linkages

Post by ArtF »

Bill:

Hmmm, fopr some reason, both of these files load and run fine. Does one crash at load for you, or when sim'ed?

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Re: Issue with shaft/gear linkages

Post by ArtF »

Bill:

I do see the log has broken in your logs, I just uploaded a fix for that.

Art
BillM
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Re: Issue with shaft/gear linkages

Post by BillM »

Art

I loaded V2.05B and the crash problem is no longer there. Under 2.04B, the file A-AutoPlaceBevels02 loaded but crashed when I tried to run the sim.

I'm trying to figure out something with sharing links to files on a google drive. As I build more extensive examples, even zipped versions of project files will exceed the allowable attachment size of messages.

The following is a link to a folder Named "Experiment to place Spur Gears Manually"
https://drive.google.com/drive/folders/ ... share_link

The folder contains two project files. One project has a pair of spur gears placed automatically by the Ticker software.

The second project file contains the same two gears except that I placed the pinion manually. The shaft spacing is calculated to be 23.11 plus an additional .17mm. Although the gears appear to move they are in fact not really meshed during simulation.

How is the gear placement done by ticker that is different from attempting to place the gear manually? I've turned on Wireframe when running the simulations. The wireframe surrounding the gears appear to be approximately cylinders rather than something that follows the outline of the gear teeth. I think I'll have to look at some of the other project files that come with Ticker to see what the wireframes look like on other objects.

Bill Michael
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Re: Bevel Gear instabilities

Post by BillM »

Art

I'm not sure if this is an issue with v2.05B or my system.
This link https://drive.google.com/drive/folders/ ... share_link is to a folder Titled Bevel Gear Instabilities.

I've noticed in the past that when I place an object such as a balance from a tass file that the model was not stable. I figured at first that the problem was the tass file. I decided to experiment with bevel gear that have a 10:1 gear ratio.

I've created two projects: BevelGearExperiments and BevelGearExperimentsV2.

I use the Ticker bevel gear creator to make the upper left gear set. After that I use the "copy Selected" tool to create the other three gear sets.

In BevelGearExperiments the upper left gear set has its pinion powered at 100rpm. In the upper right set I turned the wheel vertically and also had its pinion powered at 100rpm. The lower left and lower right gear are similar except that motors have been attached to the wheel and are 10rpm. I run the simulation at 100% motor speed so 10rpm or 100rpm are the actual rpm's. The upper two gear sets driven by the pinions become unstable whereas the lower two gear, sets driven by the wheels, appear to be stable.

If I fuse the upper right wheel shaft to the workbench, Ticker crashes.

BevelGearExperimentsV2 is almost identical to the first experiment. This time I loaded the BevelGearExperiments project and used the "copy selected tool" to mount the wheel to the upper left pinion, saved the file as BevelGearExperimentsV2 and then ran the simulation. The simulation ran. When I restarted ticker, I loaded BevelGearExperimentsV2 that I had just saved....Ticker crashes as soon as I try to run the simulation.

Quite puzzling .

BillM
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Re: Issue with shaft/gear linkages

Post by ArtF »

Thanks Bill:

Im looking into it.

Art
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