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Issue with shaft/gear linkages
Posted: Wed Apr 12, 2023 2:28 pm
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
Re: Issue with shaft/gear linkages
Posted: Thu Apr 13, 2023 1:14 am
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
Re: Issue with shaft/gear linkages
Posted: Thu Apr 13, 2023 12:08 pm
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
Re: Issue with shaft/gear linkages
Posted: Fri Apr 14, 2023 2:34 am
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
Re: Issue with shaft/gear linkages
Posted: Sun Apr 16, 2023 1:40 pm
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.
Art
Re: Issue with shaft/gear linkages
Posted: Sun Apr 16, 2023 3:30 pm
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
Re: Issue with shaft/gear linkages
Posted: Sun Apr 16, 2023 11:00 pm
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
Re: Issue with shaft/gear linkages
Posted: Mon Apr 17, 2023 12:07 am
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
Re: Issue with shaft/gear linkages
Posted: Mon Apr 17, 2023 1:42 am
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
Re: Issue with shaft/gear linkages
Posted: Mon Apr 17, 2023 12:22 pm
by ArtF
Thanks Bill:
Ill let you know what I find.
Art