I started converting that rack and pinion working paper that I circulated a few days ago into code. First pass is being done in Visual Basic to debug the approach. When Java scripts activated in AoI go south they tend to reset my PC instead of giving me nice error messages, so the two step approach is worth the extra time for me.
I've got the pinion gear done. The calculations are essentially the same as we had in the Involute Profile gear routine, exceit has a bit more robust formula development. This one is set to 14.5 degree gears only which gives us a pretty narrow range of gears that we can design using these formulae.
In the morning, or tonight, I will do the rack coding. It looks pretty simple.
According to Kiplinger, the guy who wrote the paper, Kent's Mechanical Engineers' Handbook, Design and Production, Twelfth Ed.,
Wiley, 1958 has a bit of information in the form of some advice about what size pinion gears will work with what kind of racks. I checked Amazon and there was exactly ONE (1) copy of the 1958 edition for sale. The price wasn't bad and the condition is listed as very good, so I bought it just to have backup for this coding.
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Got the rack profile done. It was easy and it looks good. Now I've got to extend that profile to let the user specify the number of teeth in the rack or its length or something like that and put a closed base on it so that it will work in AoI as a profile.
I should be able to write the script for AoI in the morning. I've pretty much got all of the code written and tested.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
I've got the Java script giving pretty much the same numbers that the VB.NET test code does for the rack polygon. I've also resolved the input differences between the existing involute profile gear script and the rack script.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
***Cool. With this I think that AoI is starting to look like more of a CAD system than BlenderCAD, despite the name... ***
If we just keep adding scripts that do useful engineering design kinds of things it should be before too long. :-)
Actually, as I said before I think that rack and pinion might be a nice polymer-oriented alternative to those threaded rods we're tending to use these days. We ought to be able to design a really light weight, low power RepRap driven by, say, those little yellow plastic G4 gearmotors. We already know how to use shaft-encoding with those. :-D
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Having trouble doing in Java a procedure that was a pain in the neck in VB.NET. Looks to be maybe even more unpleasant in Java than it was in VB.NET. Giving up for the night. It's just grind now to get it to work. Should be no big surprises.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Now the numbers for the rack polygons in the VB.NET and Java match up perfectly. Turned out that you had to differentiate between tooth counts in the pinion gear and the rack. It's logical once I figured it out, but it sure wasn't while I was in pure propellerhead mode. Silly me. :-P
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It was truly said that Java was Sun's revenge on the world when the it didn't immediately see and worship in wonder the obvious brillianceof C++ and OOP. :-S
I have never in my life encountered such a bloody brain damaged parser in a compiler. The diagnostics are about as informative as the old Error 240 (which translated, roughly, "you screwed up, buddy, but we're not going to give you even so much as a clue as to what you did wrong or even where you did your wrong thing) statement in 1960's IBM FORTRAN IV.
I'm for a couple of tylenol and bed.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Finally found the "problem" this morning. I'd accidently used a capital "I" in an "if" statement. The parser couldn't even give me a decent idea of what line the problem was on. :-s
Anyhow, I have a working script now and have blogged it. I want to polish it a bit and do things like add a variable that lets you specify the depth of the bar under the rack. Other than that, it looks pretty much done.
AoI has been giving me fits for some months recently. It seems to randomly just freeze my display and at times even reset my PC. It even does it with my new PC which is both new and powerful.
Windows XP finally decided to give me a hint about what was happening. I got an annotated Blue Screen of Death, something very rare in XP which told me that I was initiating an infinite loop in the ATI2DVAG.dll. I checked up on that and discovered that that is part of the driver for ATI graphics cards. Further, any number of applications trigger this sort of problem. I just discovered one of them in AoI.
Anyhow, I have a warrenty with Dell for this machine and its THEIR problem. :-D
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Just a note. I've been idly trying to break the rack/pinion scripts. When you try a 4 toothed pinion it overlaps with the rack if you choose a pressure angle < 20 degrees.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
I started converting that rack and pinion working paper that I circulated a few days ago into code. First pass is being done in Visual Basic to debug the approach. When Java scripts activated in AoI go south they tend to reset my PC instead of giving me nice error messages, so the two step approach is worth the extra time for me.
I've got the pinion gear done. The calculations are essentially the same as we had in the Involute Profile gear routine, exceit has a bit more robust formula development. This one is set to 14.5 degree gears only which gives us a pretty narrow range of gears that we can design using these formulae.
In the morning, or tonight, I will do the rack coding. It looks pretty simple.
According to Kiplinger, the guy who wrote the paper, Kent's Mechanical Engineers' Handbook, Design and Production, Twelfth Ed.,
Wiley, 1958 has a bit of information in the form of some advice about what size pinion gears will work with what kind of racks. I checked Amazon and there was exactly ONE (1) copy of the 1958 edition for sale. The price wasn't bad and the condition is listed as very good, so I bought it just to have backup for this coding.
Got the rack profile done. It was easy and it looks good. Now I've got to extend that profile to let the user specify the number of teeth in the rack or its length or something like that and put a closed base on it so that it will work in AoI as a profile.
I should be able to write the script for AoI in the morning. I've pretty much got all of the code written and tested.
I've got the Java script giving pretty much the same numbers that the VB.NET test code does for the rack polygon. I've also resolved the input differences between the existing involute profile gear script and the rack script.
Cool. With this I think that AoI is starting to look like more of a CAD system than BlenderCAD, despite the name...
***Cool. With this I think that AoI is starting to look like more of a CAD system than BlenderCAD, despite the name... ***
If we just keep adding scripts that do useful engineering design kinds of things it should be before too long. :-)
Actually, as I said before I think that rack and pinion might be a nice polymer-oriented alternative to those threaded rods we're tending to use these days. We ought to be able to design a really light weight, low power RepRap driven by, say, those little yellow plastic G4 gearmotors. We already know how to use shaft-encoding with those. :-D
Having trouble doing in Java a procedure that was a pain in the neck in VB.NET. Looks to be maybe even more unpleasant in Java than it was in VB.NET. Giving up for the night. It's just grind now to get it to work. Should be no big surprises.
Now the numbers for the rack polygons in the VB.NET and Java match up perfectly. Turned out that you had to differentiate between tooth counts in the pinion gear and the rack. It's logical once I figured it out, but it sure wasn't while I was in pure propellerhead mode. Silly me. :-P
It was truly said that Java was Sun's revenge on the world when the it didn't immediately see and worship in wonder the obvious brillianceof C++ and OOP. :-S
I have never in my life encountered such a bloody brain damaged parser in a compiler. The diagnostics are about as informative as the old Error 240 (which translated, roughly, "you screwed up, buddy, but we're not going to give you even so much as a clue as to what you did wrong or even where you did your wrong thing) statement in 1960's IBM FORTRAN IV.
I'm for a couple of tylenol and bed.
Finally found the "problem" this morning. I'd accidently used a capital "I" in an "if" statement. The parser couldn't even give me a decent idea of what line the problem was on. :-s
Anyhow, I have a working script now and have blogged it. I want to polish it a bit and do things like add a variable that lets you specify the depth of the bar under the rack. Other than that, it looks pretty much done.
AoI has been giving me fits for some months recently. It seems to randomly just freeze my display and at times even reset my PC. It even does it with my new PC which is both new and powerful.
Windows XP finally decided to give me a hint about what was happening. I got an annotated Blue Screen of Death, something very rare in XP which told me that I was initiating an infinite loop in the ATI2DVAG.dll. I checked up on that and discovered that that is part of the driver for ATI graphics cards. Further, any number of applications trigger this sort of problem. I just discovered one of them in AoI.
Anyhow, I have a warrenty with Dell for this machine and its THEIR problem. :-D
Just a note. I've been idly trying to break the rack/pinion scripts. When you try a 4 toothed pinion it overlaps with the rack if you choose a pressure angle < 20 degrees.