Author Topic: Dextre Capabilities  (Read 14413 times)

Offline iamlucky13

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Re: Dextre Capabilities
« Reply #20 on: 04/02/2008 06:23 pm »
Well I'd venture to guess that what makes Dextre special is being designed specifically for space...big temperature swings, light weight. There are robots on earth that have as many or more degrees of freedom.

Robotics applications often end up being so specialized that there's not a lot that can transferred from one application to the next. Motors, encoders, and controllers are relatively generic, but I'm not aware of any particular enhancements for those on Dextre.

Not to mention, ITAR doesn't restrict domestic use the same way it does international sales. A US nuclear plant operator shouldn't have too much trouble buying ITAR restricted hardware.

Offline Jim

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RE: Dextre Capabilities
« Reply #21 on: 04/02/2008 07:22 pm »
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cozmicray - 2/4/2008  1:24 PM
If developers of Space station hardware would include standard robotic repair fittings
the Mr Dextre could work on them.


That is the issue.  Things like blankets don't have "standard robotic repair fittings"

Offline mda

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Re: Dextre Capabilities
« Reply #22 on: 04/02/2008 08:34 pm »
SPDM (Dextre) principally offloads some of the EVA tasks associated with ORU changeout.  As with SRMS and SSRMS, I expect we will find that Dextre is capable of performing other duties when the need arises.  However, Dextre is not intended to replace all the capabilities of a suited astronaut; indeed, it is designed to provide operational flexibility and reduce the exposure of humans to the dangers of EVA where practicable.
Appendix C, in the publicly available link below, includes a list of tasks that were demonstrated for the robotic repair of HST.  None of these tasks were originally intended for robotic repair.  Note that these tasks incorporated tools that Dextre can support with data/power/mechanical interfaces and are demonstrated but not built and ready-to-fly.
http://gop.science.house.gov/hearings/full05/feb2/PaulCooper.pdf
Removal and replacement of MLI blankets has been demonstrated on the ground using a tool designed for Dextre's grasp and tool interfaces.  This operation was not required for the HST robotic repair operations.

Offline Joffan

Re: Dextre Capabilities
« Reply #23 on: 04/02/2008 11:37 pm »
Mostly what Dextre needs though for true Canadian repair capability is a duct tape dispenser. Got any of those in your odd tools set, MDA?
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Offline A_M_Swallow

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Re: Dextre Capabilities
« Reply #24 on: 04/03/2008 01:03 am »
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DMeader - 2/4/2008  6:21 PM

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A_M_Swallow - 31/3/2008  10:09 PM
Sounds like someone forgot to include pliers in Dextre's tool kit.

I have pliers in my toolkit, but I wouldn't use them to tie my shoes. The manipulators on Dextre were designed to grip specific things, just like my pliers were not meant to grip shoelaces.

You would use your hands to tie your shoes.  Hands were not designed to tie shoes but they can do it.

Offline The-Hammer

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Re: Dextre Capabilities
« Reply #25 on: 04/03/2008 01:13 am »
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A_M_Swallow - 2/4/2008  9:03 PM

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DMeader - 2/4/2008  6:21 PM

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A_M_Swallow - 31/3/2008  10:09 PM
Sounds like someone forgot to include pliers in Dextre's tool kit.

I have pliers in my toolkit, but I wouldn't use them to tie my shoes. The manipulators on Dextre were designed to grip specific things, just like my pliers were not meant to grip shoelaces.

You would use your hands to tie your shoes.  Hands were not designed to tie shoes but they can do it.

But shoes were designed to be tied by hands. The blankets weren't designed to be worked on by Dextre.
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Offline robertross

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Re: Dextre Capabilities
« Reply #26 on: 05/07/2008 02:36 am »
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Joffan - 2/4/2008  8:37 PM

Mostly what Dextre needs though for true Canadian repair capability is a duct tape dispenser. Got any of those in your odd tools set, MDA?

That's funny...instead on the Canadarm2, it would be called the "Red Green Machine"   ;)

Offline Steve G

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Re: Dextre Capabilities
« Reply #27 on: 05/07/2008 05:49 am »
All the non-Canadians are scratching their heads at that one!

Offline robertross

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Re: Dextre Capabilities
« Reply #28 on: 05/10/2008 02:05 am »
For those who don't know Red Green, he's a essentially Tim the Toolman Taylor with a roll of duct tape to fix anything (ANYTHING!!!). Of course it's Canadian, so picture a guy in suspenders, living in a log cabin in the woods, and a little weird. At least he's got ingenuity!

Actually Dextre seems like the perfect technology transfer for space surgeries, remote operated. I know they have this out there, but for use in exploration missions, this has great potential.

For what Dextre can do on the ISS, as long as it has it's purpose-built grapple points (smaller than PDGFs), it can latch on. It may not be able to replace the batteries, but I'm sure it will be a welcome addition to a SARJ repair.

Offline tankmodeler

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Re: Dextre Capabilities
« Reply #29 on: 05/13/2008 04:08 pm »
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robertross - 9/5/2008  10:05 PM
For what Dextre can do on the ISS, as long as it has it's purpose-built grapple points (smaller than PDGFs), it can latch on. It may not be able to replace the batteries, but I'm sure it will be a welcome addition to a SARJ repair.
Actually, I do believe it can replace the batteries as they were designed as ORUs with the correct intefaces (could be wrong on that, mind you). On SARJ repair it would be pretty useless, actually, because none of the hardware in the SARJ has the correct interfaces.

Jim has hit the nail on the head for the base capabilities of the SPDM. If something doesn't have the right grapple fixtures, SPDM can't grab it. It's not like a set of waldoes with fingers that can handle anthropomorphic tools.

As for the Hubble tool kit, well it was in development when the program was cancelled but the tools weren't finished, so there's nothing from that to use on the station. The benefit, from an ISS operations point of view, was that the development did show that we could design tooling for SPDM that, with some forethought, could allow us to perform some tasks that weren't originally designed for the SPDM. If we hava a lot of lead-time we can develop the specific tools to do some extra tasks.  It's very much on a case by case basis so no generic statements can be made about any specific case.

Regarding gripping insulation blankets, well, no, there isn't a real ability to do that with enough certainty to call it a "capability". Sure you could grab at a loose piece of blanket, but you wouldn't be able to really tell what you were doing or be sure how or where you had grabbed it. Pretty useless from an operational point of view. If you "just" wanted to poke a loose end back in place for some really important reason, it might be possible to jury rig a rod of material or a tool with a micrograpple fixture and have the SPDM do that, but it's definitely a contingency type operation and you couldn't expect a lot of satisfaction from the job. Besides, by the time you have done an EVA to get the tool out to the SPDM, it's probably better to put that same astronaut out on teh SSRMS to do the job. He/She will be much better at it.

SPDM isn't the answer to everything. It doesn't eliminate EVAs. What it does is reduce the number required for routine tasks and that's enough reason to have it. Like every other system we've provided NASA, once it's in use and everyone's comfortable with it, they'll find other things it can do to help out. Let's face it. No-one was ever supposed to hang an astronaut off the OBSS while grabbed by the SSRMS to fix a balky solar array. When off-nominal situations come up having extra capabilities gives engineers with ingenuity new ways to solve tricky problems. We like to think that our systems provide a cache of those sorts of extra capabilities when they really need them.
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Offline catfry

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Re: Dextre Capabilities
« Reply #30 on: 05/13/2008 04:46 pm »
Thank you tankmodeler.

Offline janmb

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Re: Dextre Capabilities
« Reply #31 on: 05/14/2008 08:50 am »
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catfry - 31/3/2008  9:10 PM

This thing with walking end over end with Dextre attached.. Does that mean the combine could be operated with Dextre attached to Station, Canadarm attached to Dextre, and the free end moving structure or EVA'er around. Structurally would the combine be able to handle the same loads as in non Dextre mode? I can't thing of any reason you would want to do this but now I'm curious.

Whether it is structurally certified for that mode of operation I don't know, but we can always to a bit of deductive reasoning...

The only reason why you would want to at all, would be to gain more reach. Contingencies like the Parazinsky solar array repair comes to mind. Then again, DEXTRE would far from always be a sufficient reach extension for purposes like that.

Secondly, I would assume the more standard mode of operation would be the other way around, SSRMS atteched directly to station, using DEXTRE as an extension in the other end. This may obviously cause clearance issues you could avoid by doing it the other way around, but having a real hard time imagining any such cases.
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Offline synchrotron

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Re: Dextre Capabilities
« Reply #32 on: 05/14/2008 10:55 am »
Dextre is not designed to provide a base for the SSRMS.

Offline synchrotron

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Re: Dextre Capabilities
« Reply #33 on: 05/14/2008 11:00 am »
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tankmodeler - 13/5/2008  3:08 PM
Regarding gripping insulation blankets, well, no, there isn't a real ability to do that with enough certainty to call it a "capability". Sure you could grab at a loose piece of blanket, but you wouldn't be able to really tell what you were doing or be sure how or where you had grabbed it. Pretty useless from an operational point of view. If you "just" wanted to poke a loose end back in place for some really important reason, it might be possible to jury rig a rod of material or a tool with a micrograpple fixture and have the SPDM do that, but it's definitely a contingency type operation and you couldn't expect a lot of satisfaction from the job. Besides, by the time you have done an EVA to get the tool out to the SPDM, it's probably better to put that same astronaut out on the SSRMS to do the job. He/She will be much better at it.

Thermal blanket handling tools have been tested under teleoperation to an R&D level with the SPDM-GT.  Dexterity-wise, they are more effective than EVA gloves.  An astronaut would need a tool with similar tip characteristics to perform the same task.

Offline A_M_Swallow

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Re: Dextre Capabilities
« Reply #34 on: 05/15/2008 03:17 am »
Can new tools for Dexte's tool kit be transferred by simply leaving them in an airlock and picking them up using say the SSRMS?
This would save an EVA.

Offline janmb

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Re: Dextre Capabilities
« Reply #35 on: 05/15/2008 11:57 am »
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A_M_Swallow - 15/5/2008  4:17 AM

Can new tools for Dexte's tool kit be transferred by simply leaving them in an airlock and picking them up using say the SSRMS?
This would save an EVA.

Could.. or would? Most things are possible - few things are desirable.

The preferance would certainly be to fly that new tool kit as external cargo that could be deployed directly from the payload bay.

And if you had to fly it internally (shuttle being decomissioned for example), I cannot imagine the preference would be anything other than taking it outside as (part of) an EVA.


If we are gonna theorize, I guess, if you could find space to fit the tools with double fixtures - both DEXTRE and Kibo compatible, you could use the Kibo airlokc for completely robotic transfer to the outside - but all this is obviously depending on both finding space on the tools to fit both fixtures, as well as the size of the Kibo airlock itself.
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Offline tankmodeler

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Re: Dextre Capabilities
« Reply #36 on: 05/15/2008 12:30 pm »
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synchrotron - 14/5/2008  7:00 AM
Thermal blanket handling tools have been tested under teleoperation to an R&D level with the SPDM-GT.  Dexterity-wise, they are more effective than EVA gloves.  An astronaut would need a tool with similar tip characteristics to perform the same task.
Agree. If you have the right tools, you can possible/probably do it better than an EVA. At the moment, though, I don't think those tools have been actually flight-designed or flown, right?

The thing with special tools, though, is that they tend to be desinged to do one sort of thng very well, but are frequently not too good for other tasks. You need to identify a standard sort of function to design a tool to perform that function.

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Offline Jim

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Re: Dextre Capabilities
« Reply #37 on: 05/15/2008 02:06 pm »
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A_M_Swallow - 14/5/2008  11:17 PM

Can new tools for Dexte's tool kit be transferred by simply leaving them in an airlock and picking them up using say the SSRMS?
This would save an EVA.

EVA is needed to open the airlock.  Also the tools would be too big to be carried internally

Offline hutchel

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Re: Dextre Capabilities
« Reply #38 on: 05/15/2008 03:52 pm »
Actually I can easily suggest that once you get the PDGF's installed on the Russian segment, the opportunity arises that you would want to use one of those as the base for the SSRMS and then use DEXTRE from there.  The question is (and I don't know the various reaches/ distances) would the arm have to inch-worm walk such that it would need an intermediate step to reach the end of the Russian segment.  If that's the case, that intermediate step would have to use DEXTRE as the home.  Now I realize based on the rest of the thread, there is probably little/nothing down that end of the station that DEXTRE is designed to work on, but I'm thinking contingency, future capability - esp if you ended up have an external cargo capability on a future version of ATV.  You would need to rehome SSRMS to the Russian end to grab the ORU and then move it back to where you will store/need it.

Offline Riley1066

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Re: Dextre Capabilities
« Reply #39 on: 06/08/2008 01:41 am »
Regarding the MLI blanket issue with Dextre's grippers ... aren't most of the ORUs stored on the exterior of the ISS covered with MLI blankets anyway? How is Dextre going to swap out ORUs on the ISS if they are all wrapped in MLI?  Or will the Only ORUs that Dextre changes be on the Express Logistics Carriers, leaving ORUs on the External Stowage Platforms for spacewalking Astronauts?
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