Reply with QuoteI have only seen one other machine similar to the one you have linked to, and it's made by Index. http://www.index-werke.de/de/deutsch/546_DEU_HTML.htm
TriPlanar Machine
Hi Guys,
I'm just kinda obsessed with parallel machines and found this amazing design called a "TriPlanar" from a German University recently.
There's a video with explanation of the motors but in German only. Looks like a 2D linear stepper motor/table. Amazing technology!
http://rtm.upb.de/forschung/triplanar/index.php
Quite a few videos here;
http://rtm.upb.de/forschung/triplanar/multimedia.php
I'm having fantasies of the CNCBrain controlling one of these babies.
Each (lower) leg could be controlled by a small x-y table. Arguably mechanically simpler to build than a "traditional" Hexapod. Only 3 ball type joints at the lower legs and 6 roller bearings at the platform for 6-axis control.
If instead of the XY tables one used a linear actuator, this reduces to 3-axis and would be exactly like the Linapod or "Triaglide" design.
It could operate in any orientation too as you can see.
Always the biggest problem with these PKMs is the control. At first thought it does not look to be trivial.
Any thoughts comments?
Mark
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I have only seen one other machine similar to the one you have linked to, and it's made by Index. http://www.index-werke.de/de/deutsch/546_DEU_HTML.htm
i can't grasp the profits over just mounting a x-y table to the ceiling with a z-axis hanging from it and placing the workpiece underneith of this construction.
though i can grasp the profits of a x-y mounted to the ceiling like no coolant in precious places ,gravity taking up some backlash maybe and just looking beautifull.
just the x-y with a mounted z will stay 3-axis wich is no prob for THE BRAIN or any other prog.
can some1 pls explain why it should be better or cheaper building such a triangle construction with roller joints and alikes wich i expect to get somewhat expensive when needing them to be free of any backlash.
this post was posted assuming there is no limit to how stupid a question may be before it is disqualified to being answered.
thx in advance
Finally CHIPS you can have as much as you can without the doc. complainting about your cholesterol.
Hmmm, interesting. It wasn't really a question I was asking was it? Isn't this about discussion and sharing info? "Stupid question disqualifying itself"?Originally Posted by ironDigit
Yes, how stupid of the guys in this German university to be wasting what must be substantial amounts of money and time in this research.
Why don't you let them know, they may appreciate your input on that.
As a matter of fact, why don't you do some rounds around other universities while you're at it?
Research is just that, exploration into areas previously unknown. It is also partly to see how such devices operate in real life. Hopefully there will be commercial benefits if 2D motors were easy to make anyway.
Perhaps one day no? Or do you want no progress which ever direction that will takes us? Oh,... XY tables that's right.
In other words, people have to TRY ideas.
One of the reasons you don't see too many PKMs is that they expensive. Both the control system and hardware, although the control system is far less of an issue now days.
You're complaining about antibacklash expensive bearings in this design?
What about the backlash in the ballscrews themselves, the ball screw holder, the motor coupler and the linear errors in the guideways? Do you know how errors propagate in this TriPlanar machine design? Are they worse than a cartesian design or some reason?
You know what a Hexapod looks like? How many bearings are used for the end universal joints? Only 2 for each side on this design.
As for the advantage of having this thing on the ceiling, the vids just show it being used in either configuration, on ceiling or floor. It's a research program! They can. They probably find it easier practically speaking to mount it "upside down". Big deal.
The advantage of this configuration as opposed to an XY and Z stuck on a roof? How about 6-axis movement instead of three?
Yes, you surely know how to get at the heart of the discussion.
Mark
The Blight,
Thanks for that link. Nice, I hadn't seen this Linapod (Hexaglide) before. Not many of these machines in real products are there?
You can see what a small working volume it has for it's size. Well, it looks quite small to me anyway.
Yet another reason they aren't many of these around. They're really designed for particular applications in mind I suppose.
Mark
This machine must have been designed for some very specific function. I cannot see the practical advantages of such a machine in the real world. Those 3 moving carriages up top would be hugely expensive to build, and I see no method of moving the Z axis up and down. But if you know the Germans, they have a tendency toward large and highly complex mechanisms. Their WW II tanks were a perfect example- monstrous in size and very complicated leaving them mostly broken down and stuck in the mud while US and Russian tanks were built in the thousands and simply overwhelmed them with reliability and numbers.
Unless someone who can read German can enlighten us, I don't know if it is designed for a specific purpose. It appears to be just a research program for this design. Perhaps to find out what advantages, if any, there are in the real world. Refine and assess control issues. Profs always need poor unfortunate students to do their work for them.
Their may be some specific applications it could excel at.
The 2D motor looks expensive alright. I don't think it's that complex in principle though. No, don't see them rolling off the product line just yet! Just compare the (mechanical) complexity of the Hexapod with this one and I see obvious advantages in the design. Only 1 degree of motion at the top of the delta shaped struts as opposed to 2 for a uni joint on a Hexapod. Isn't a Uni joint more complex than a single bearing? Everything counts to eliminate any errors at the business end.
The Z-Axis movement is simply attained by moving the "pad" all outward or inward. All in the vids.
From what I have read, one of the advantages with PKMs in general is that positioning errors don't add like Cartesian systems.
You don't have "stacking" errors like a Cartesian system. For e.g. a rotary table on top of the XY. The table has some linearity error and the rotary table run-out error.
I'm talking about the inherent mechanical design not any compensation that could be done on an Cart system
Anyway, I think it's interesting although perhaps very far from practical at this time.
Thanks for you comments.
Mark
Maybe this will help with the translation?
I use the Google translator (works most of the time)
http://translate.google.com/translate_t?hl=en
.
Free DXF - vectorink.com
Lets see a cutter on the TriPlanar machine please.
Unless you are doing extremely high speed cutting with resonant tooling and slow down the feed until you can't see the chatter marks. If its got to be this good, move at 3 M/sec, 1HP feed power, with 5 micron resolution, with 100KG side load on cutter. In their dreams. What a waste of resources.
Great type of mechanism on flight simulators. What's new about this except that it has become fragile and added lots of extra joints for lost travel, and given someone a job for years writing custom software to drive it.
Hitting a golf ball with a cricket bat, I reckon.
Fellas. Put a spindle motor on it and a chunk of metal and discover chatter.
Last edited by neilw20; 07-13-2008 at 02:24 PM.
Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. THREE ways to fix things: The RIGHT way, the OTHER way, and maybe YOUR way, which is possibly a FASTER WRONG WAY!
The machine I linked to is actually a lathe, and it is used. I have never seen it working, but I have some colleagues who have.
You should take a look at some of the other index machines. Some of the multi spindle machines are truely amazing. These machines are also quite expensive, but the quality is supreme.
Sharpshooter: WWII data from the discovery channel?
Naw- History channel- Discovery is all about fishing in Alaska.
The Blight,
I didn't even twig that it was a lathe, I've seen these arrangements before but not as a lathe. I've had thoughts about this myself but never knew why it's never been tried. Now I know.
By the way, thanks for your open mindedness.
Regards,
Mark
fo shizzle......
well can some1 pls share with me then wath this machine can do, that a x-y hanging from fishingwire can't?
And using the educational purposes excuse is plane sorry ,cause this kind a machines been around for a long time and have already proved both expensive as complicated plus hard to expand when new needs arise.And(i must admit there is alot of and's in my post by now)the displayed design is quite limited at it's capabillity's as overcomplicated by .......and it can not perform anything wonderfull for as far as i can tell
here is an example of what these guys are trying to achieve :http://www.cybamantech.co.uk/?page=cybaman
the cybaman contrary to this german design CAN do some neet tricks the german machine or a regular x-y table standing ,hanging or even floating on a ship or spacecraft can NOT.
i hope i shared enough this time not to be disqualified again.Since i do still believe that sharing info is not just yaysaying and blowing smoke up our spindle trueholes.
maybe you can tell me about this wonderous elements you spoke of like : motormounts and ballscrews wich experience backslash and comma's cause offcourse these are new to me.
Finally CHIPS you can have as much as you can without the doc. complainting about your cholesterol.
The machine he pointed to is essentially a 5 axis mill. It can drill holes or mill pockets at an angle which only a 5 axis machine can do. It is a little more limited then a 5 axis machine in the sense that it does not have a full 180 or 360 degree pivoting range (or whatever you call it). If you watch some of the videos on the first link, you will see the machine using this function.
As far as I can see, there is only a need for ball bearings in that design, and they are far cheaper then linear rails. So a lot of cost is saved there. There is no ball screw in this design, so there is no cost there (no service cost either. Ballscrews wear out pretty fast on CNC machines). There should be no slop there either if the preload on the bearings are correct.
The cybaman machine is a nice machine, but can it do something a 5 axis mill can't do?
And last. I'm glad you are not a teacher (if you are, I'm just glad I'm not one of your students). Doing research on something that is working is a valid point. It might be too expensive at the moment, but at some point the software and hardware to drive it will or might come down to a reasonable price. At one point cars were so expensive that most people could not afford them, but now allmost every family has one. I hope these guys continue to do research, so that we one day might end up with some amazing machines.
Hi The Blight.
Hi there.
I direct you to post #10.
Can it hack real work ? which is just about a minimum useful machine.
Even my SX3 is a bit more of a toy, and can shear off a 10mm cutter feeding straight through a tiedown bolt instead of going around it. (destination X variable got clobbered)
Will it pass the test. Hope it does not weigh more than 1/2 tonne to do this !
Show some real results cutting steel or some metal. We (IMHO) need convincing. The Spruce Goose could fly too (in ground effect).
Last edited by neilw20; 07-13-2008 at 08:52 PM.
Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. THREE ways to fix things: The RIGHT way, the OTHER way, and maybe YOUR way, which is possibly a FASTER WRONG WAY!
Thats why it is a research project. To make it better. But seems like you guys are all against research. If you have nothing positive to say in this topic, then maybe you should leave it alone. Zathras wants to share ideas, and not hear about how you guys thinks this is a waste of time.
One of the videos actually shows it cutting aluminum. It doesn't remove a lot of material, but it gets the job done. I would look at it more as a router, and not a mill.
Anyway! It is a nice concept! It might actually lead to something some day, even if you fail to see that.
I saw the Cyberman a while ago, very interesting machine and I like it. Don't think many machines could match it in some respects. The immediate limitation I see with it is that it probably cannot handle a heavy load on the end of the arm.
Look at the envelope too, pretty small! Maybe great for jewelry(as shown in vids) and fine small complex parts I imagine.
Ah yeah,
There seems to be a certain perspective on this device that some people just can't get past.
Every mechanical device has it's limitations and therefore application spread.
No one is suggesting it (the TriPlanar) could be used for machining gigantic bearings for the next super-large-mega-telescope. (http://medusa.as.arizona.edu/lbto/teleindex.html)
Neilw20;
Can it do real work? Of course it can but it will have it's applications limited like any other machine.
I'm not sure if you are making comparisons with the actual machine shown or are talking about the design in general.
There's clearly no way what you describe will happen with this thing. If you look at the specs it's just under 3kg!
However, if you're talking about it's capacity in a larger machine of this design, I dunno. Maybe that's what they will find out if they suspect it could work. Maybe they only envisage particular uses for it on soft materials like wood?
BTW, there is a vid of it cutting metal. Granted it was probably done using very light cuts! Always want to start slow and work your way up.
I would very much disagree with your cynical comment about wasted resources in research. IronDigits also commented on this type of thing being done before and already proven to be complicated and expensive.
This particular design appears to be new, at least to my knowledge it is.
No doubt there have been others before it that have failed. That is the nature of research humans conduct.
Of all the trillions of ideas people have had throughout history, only a tiny fraction of them work! How do we know this? Because we tried a lot of them, we explore, we fail and try again.
I can say with complete certainty, there will be other machine designs in the future that may lead nowhere. The only way we will find out what works in real life is by trying.
I wouldn't have it any other way!
If they had built some monstrosity the size of a truck then I may agree with you funds could have been better spent, but never on the PhD student working on the code (or whatever).
Plonk it on top of the sum total of human knowledge as happens everyday and say; "been there, done that, doesn't work!"
IronDigits;
To sum up above; It has nothing whatsoever to do with so called "excuses".
Yaysayers are not what I'm looking for, discussion with reasoned arguments is. Your first comment (and that's all it was) discussed nothing. You simply stated what a stupid question this all was. Is that what you call "sharing info"? Where are the arguments in this?
------------------
God almighty! All I was trying to do was to share a bit of info and start a discussion again on these sorts of machines.
Yes The Blight has captured my thoughts exactly. If you are just coming to this thread just to junk it, then go somewhere else.
well hooray for science cause if that thing ways just 3kg i'm convinced !
btw : when , in my first post i said somehing about disqualifications i was referring to my own post so i hope that didn't demotivate anyone.
but since learning more about this machine like it weighing 3kg(i love kg im european)i can see it suspended above a ?workshopcarliftbridge? doing some artworks while the oil is being refreshed or in any productionline enabling the wokpiece to conveniently slid by on a conveyorbelt. so thx for sharing so far guys.
Pls can some1 share with me, what kind of highly cost-effective way of motion controlling mechanicle force is at work cause i hope this force may be with all of us very soon since to me and i think lots of other members & lurkers only one of those three "(don't even know what to call m)devices that hold the hole thing to it's base and seem to make all the smooth moves happen ,would make a very nice x-y for a cheapo light ass portable router.Is it magnetic or something ,cause yall promised me no costly and highmaintenance slides and screws,
keep sharing now !.
Finally CHIPS you can have as much as you can without the doc. complainting about your cholesterol.
Ha!!
Isn't this interesting..... essentially the same idea here;
http://crrl.poly.edu/manip/
Now I know what these 2D motors are called; "Sawyer Motors"
Never heard of them before.
http://crrl.poly.edu/~tlng/Sawyer/sawyer.html
and here;
http://crrl.poly.edu/motors/
Found this almost by accident. Not much here but just for anyone's interest.
