IPB

Welcome Guest ( Log In | Register )

38 Pages V  « < 3 4 5 6 7 > »   
Reply to this topicStart new topic
ExoMars
mcaplinger
post Jun 14 2006, 02:24 AM
Post #61


Senior Member
****

Group: Members
Posts: 2192
Joined: 13-September 05
Member No.: 497



QUOTE (djellison @ Jun 13 2006, 02:58 PM) *
I've not actually heard of computing performance being a limiting factor for spacecraft - but I may have missed such reports.

Generally, Doug is right. There's a lot of semi-informed speculation on this thread, less real info. The RAD750's performance is comparatively poor from two factors: first, the process changes that make its internal registers immune from radiation-induced bit flips slow down the clock speed considerably, but more importantly, external components, also rad-hard, are running more slowly, as are the busses. The RAD750 on MRO doesn't even have an L2 cache and it's using a 33-MHz PCI bus.

If you wanted a non-mission-critical computing resource that didn't have to be totally bulletproof against radiation, there are many options, including commercial processors that happen to be latchup-immune and various gate arrays. For our MSL instruments we are using Xilinx FPGAs; clocked at 40 MHz they are many times faster at doing JPEG compression than code running on a fast desktop system would be.

Rover speed is typically limited more by the capabilities of the drivetrain and the overall power budget. It's not like MER would be going 50 KPH with a faster processor. Despite what AI people will try to tell you, we don't know how to write autonomous nav software regardless of how fast our processors are.

And finally, MIPS (aka "Meaningless Indicator of Processor Speed") is a bad metric for judging computer performance in this or any other problem domain.


--------------------
Disclaimer: This post is based on public information only. Any opinions are my own.
Go to the top of the page
 
+Quote Post
RNeuhaus
post Jun 14 2006, 02:59 AM
Post #62


Senior Member
****

Group: Members
Posts: 1636
Joined: 9-May 05
From: Lima, Peru
Member No.: 385



QUOTE (mcaplinger @ Jun 13 2006, 09:24 PM) *
Rover speed is typically limited more by the capabilities of the drivetrain and the overall power budget. It's not like MER would be going 50 KPH with a faster processor. Despite what AI people will try to tell you, we don't know how to write autonomous nav software regardless of how fast our processors are.

And finally, MIPS (aka "Meaningless Indicator of Processor Speed") is a bad metric for judging computer performance in this or any other problem domain.

I was thinking that too. The AI is one of the software components which needs a fast CPU, lots of RAM in order to perform the harzard avoidance analyze more sophisticated and perform the required action with a much better performance as the MER does. A much improved AI will need much less from Earth remote direction and hence the rover will have greater autonomy to perform the core activities more productively in Mars.

It is true that the MIPS "Millions Instructions per Second" is an old comparision computing power that actualy is obsolete except it is only good to have an idea about how the younger brother computer is improved against the older brother if the model or serie is about the same.

Well, I seems like that the AI is a new field that must work harder to improve the space exploration by improving the autonomy capabiltity of probe or rover. If the microprocessor RAD750 is limited in its computing capability, so why don't put more microprocessors in parallel. The most powerfull computers work with many processors in parallel.

In few words, I think the AI is still very new and I speculate that in the future, the AI will play with a much greater importance. Imaginate that JPL tell the rover: "Please go there, over that dark spot and tell me what is that up? wink.gif

Rodolfo
Go to the top of the page
 
+Quote Post
Guest_DonPMitchell_*
post Jun 14 2006, 03:23 AM
Post #63





Guests






The Bell Labs inventor of UNIX, Ken Thompson, was once on an ACM panel discussion and the question was posed, "What is the major contribution of AI to Computer Science". Ken answered, "Fraud!". That was probably true a a few decades ago, when MIT and Stanford AI labs dominated the field. You had grandiose claims and no real results. One famous Stanford profressor, giving a demonstration of an English-language query system, accidently hit the carriage return twice -- the program printed the answer to his question, and then printed the answer to the next question, which he hadn't typed yet.

These days, I would take a look at AI development in the computer-game industry. Games, as frivolous as they may seem, are the driving market force behind a lot of elements of the computer industry. Why does the graphics card in your PC go faster than an SGI workstation? Why do the Intel and AMD processors do vector math? Why was the Cell Processor developed? PC games. That is the commercial application of megaflops.

[attachment=6232:attachment]

Now let's talk radiation hardened computers. Here is a good solid Russian solution!
Go to the top of the page
 
+Quote Post
mcaplinger
post Jun 14 2006, 03:45 AM
Post #64


Senior Member
****

Group: Members
Posts: 2192
Joined: 13-September 05
Member No.: 497



QUOTE (RNeuhaus @ Jun 13 2006, 07:59 PM) *
If the microprocessor RAD750 is limited in its computing capability, so why don't put more microprocessors in parallel.

Three answers: mass, power, and cost. A single flight RAD750 board uses tens of watts, weighs over a kilo (just for the board, not counting card cage, etc.) and costs, last time I checked, nearly a million dollars. And we don't need more cycles anyway.


QUOTE (DonPMitchell @ Jun 13 2006, 08:23 PM) *
These days, I would take a look at AI development in the computer-game industry.

Games have driven graphics development, sure. But I would argue that there's nothing like real AI in any game out there. Real AI of a sort useful for rovers would be able to sense the environment and react/plan accordingly. Games just don't have to do that; they define the environment, there's no need to sense it.


--------------------
Disclaimer: This post is based on public information only. Any opinions are my own.
Go to the top of the page
 
+Quote Post
helvick
post Jun 14 2006, 06:48 AM
Post #65


Dublin Correspondent
****

Group: Admin
Posts: 1799
Joined: 28-March 05
From: Celbridge, Ireland
Member No.: 220



QUOTE (mcaplinger @ Jun 14 2006, 03:24 AM) *
Generally, Doug is right. There's a lot of semi-informed speculation on this thread, less real info.
...
And finally, MIPS (aka "Meaningless Indicator of Processor Speed") is a bad metric for judging computer performance in this or any other problem domain.

Thanks for jumping in Mike - you are dead right on both of the above. I used Mips quite arbitrarily and without enough qualification but the intention was to find some metric that emphasized how extremely different the stuff that has to fly is from what we can put in general purpose PC's.

On the issue of rover speed I was trying to show that there are situations where the current rovers' progress is, to some degree, limited by the electrical power that the onboard computing systems consume during the compute intensive semi autonomous driving modes. I agree that any "improvement" in that would not necessarily lead to a faster rover but it would free up some power for other things.
Go to the top of the page
 
+Quote Post
Bob Shaw
post Jun 14 2006, 09:34 AM
Post #66


Senior Member
****

Group: Members
Posts: 2488
Joined: 17-April 05
From: Glasgow, Scotland, UK
Member No.: 239



QUOTE (DonPMitchell @ Jun 14 2006, 04:23 AM) *
Now let's talk radiation hardened computers. Here is a good solid Russian solution!


Don:

What is it?

Bob Shaw


--------------------
Remember: Time Flies like the wind - but Fruit Flies like bananas!
Go to the top of the page
 
+Quote Post
RNeuhaus
post Jun 14 2006, 04:45 PM
Post #67


Senior Member
****

Group: Members
Posts: 1636
Joined: 9-May 05
From: Lima, Peru
Member No.: 385



QUOTE (mcaplinger @ Jun 13 2006, 10:45 PM) *
Three answers: mass, power, and cost. A single flight RAD750 board uses tens of watts, weighs over a kilo (just for the board, not counting card cage, etc.) and costs, last time I checked, nearly a million dollars. And we don't need more cycles anyway.

Good to hear your comments! smile.gif

About the weigth, its is by far heavier than any normal microprocessor and its peripheral components; its price is prohibitive for any commercial applications. However, a more powerfull microprocessor will save money on the other side. It is that we are going to learn the results quicker and hence the mission won't take as long as does MER, hence saves money to the mission operations.

Hence, I see that AI is a very promisory role for future space missions and NASA must pay greater efforts on that. I have enclosed a interesting reports in which make lots of emphasis about the importance of autonomy for a greater producivity of mission. The productivity depends much by a powerfull microprocessor.

QUOTE
For rovers and robots, we're trying to design autonomous intelligent agents that can survive in hostile environments.


QUOTE
Mars is a lot more complicated than that, but this particular technique is based on trial and error, so it's self-learning. We train the robots with something called a "fitness function," but we're not to clear on how to build to most optimal training regime. We want to mix and match different types of environments to get the robot to learn to be robust, so no matter what situation it finds itself in, it can still navigate.

But spacecraft engineers are notoriously conservative, and they don't like new things. So it's a constant battle to try and convince the agency that what we're doing will work and that it's better than the technique they currently have. That's always an uphill struggle.

So AI is still a novel and with a radiation hardened microprocessor up to date will help to improve the AI.

A Naturally Inspired Robot MarExo

The problem resides of a very long time lagging between the new microprocessors and the radiation-hardened ones. Mike, do you know why it is?

Rodolfo
Go to the top of the page
 
+Quote Post
Guest_DonPMitchell_*
post Jun 14 2006, 05:04 PM
Post #68





Guests






QUOTE (Bob Shaw @ Jun 14 2006, 02:34 AM) *
Don:

What is it?

Bob Shaw


It's the program timing unit that controls the course-correction engine in Mars, Venera and Fobos probes.
Go to the top of the page
 
+Quote Post
RNeuhaus
post Jun 15 2006, 03:37 PM
Post #69


Senior Member
****

Group: Members
Posts: 1636
Joined: 9-May 05
From: Lima, Peru
Member No.: 385



Brits Unveil Latest Robot To Search For Life On Mars

British scientists on Monday took the wraps off a prototype craft to search for signs of life on Mars, hailing it the smartest piece of equipment ever designed for exploration of the red planet.


Details about Bridged
  • 1 Is an autonomous robotic scientist
  • 2 The project costs $US 910 millions
  • 3 Measures 3 meters by 1.8-meter
  • 4 It costs $US189 millions
  • 5 It will cover more ground (range) than MERs.
  • 6 It will have incorporated smarter sensors and adjustment for a safer landing.
  • 7 It will be a solar powered.
  • 8 It will be tested in Spain and Tenerife to prove its capabilities.
  • 9 It is expected to weigh 150 kg in Earth (lighter than MER with 186 kg).
  • 10 It will have a life marker chip
  • 11 It will incorporate a micro seismometer to facilite the water search.
  • 12 It will have a long drill tube of 2 meters.
  • 13 It includes an orbiter and a descent module
  • 14 The orbiter will operate as a data relay satellite.
Then wait beyond than 2011 for knowing the happening news.

Rodolfo
Go to the top of the page
 
+Quote Post
helvick
post Jun 15 2006, 04:49 PM
Post #70


Dublin Correspondent
****

Group: Admin
Posts: 1799
Joined: 28-March 05
From: Celbridge, Ireland
Member No.: 220



QUOTE (RNeuhaus @ Jun 14 2006, 05:45 PM) *
Hence, I see that AI is a very promisory role for future space missions and NASA must pay greater efforts on that.

I must say that I'm fully in agreement with Mike on the liklihood of "AI" being of any benefit to rovers any time soon. More computing power will help some limited functionality and the power consumption\weight savings that might be made by space rating current computing tech would be worth some effort but the end result will not be AI or anything close.

I've worked on and with such systems in the past and they have always disappointed. Fully autonomous AI is still 20+ years out even here on earth with effectively unlimited power and size constraints.We still do not have even the beginnings of the theoretical foundations of what will be needed to build an AI.

Assisted rather than artificial intelligence is something that has made significant strides but the only places where Artificial Intelligence has made any progress have been in well defined domains (e.g. Chess playing systems like Fritz) but even those are really just variants on assisted intelligence where the only brains belong to the developers or users. "Expert" systems, genetic algorithms, simulated annealling, neural networks, bayesian filters and the rest are useful in extremely well defined problem domains but each one has been over hyped.
Go to the top of the page
 
+Quote Post
hendric
post Jun 16 2006, 05:49 AM
Post #71


Director of Galilean Photography
***

Group: Members
Posts: 894
Joined: 15-July 04
From: Austin, TX
Member No.: 93



What's your thoughts on the DARPA challenge? AI or not, they did essentially do what the MERs do, except at 30+ miles per hour, usually using multiple high-end machines to manage the sensors and AI. With MRO quality imagery and a Mars GPS system, rovers going 1-5MPH on their own should be reasonable.


--------------------
Space Enthusiast Richard Hendricks
--
"The engineers, as usual, made a tremendous fuss. Again as usual, they did the job in half the time they had dismissed as being absolutely impossible." --Rescue Party, Arthur C Clarke
Mother Nature is the final inspector of all quality.
Go to the top of the page
 
+Quote Post
djellison
post Jun 16 2006, 06:20 AM
Post #72


Founder
****

Group: Chairman
Posts: 14344
Joined: 8-February 04
Member No.: 1



We don't have a Mars GPS system, and we're highly unlikely to have one within a couple of decades - however some of the hazard avoidance and image interp. of the Darpa winners is fantastic and I'm hoping that the US Military doesnt keep it all to itself and some algorythms can make it through to potential planetary rovers in the future.

But - and it's a big but - and likely to be so for a very long time - those DARPA vehicles are using essentially mobile super-computers compared to anything put into space. Maybe it goes around in circles a little bit

No powerfull space-suitable CPU's available....so no high processing requirements ever made
No requirement thus no real shotcoming in the availability of more powerfull processors etc etc.

Doug
Go to the top of the page
 
+Quote Post
Guest_DonPMitchell_*
post Jun 16 2006, 07:17 AM
Post #73





Guests






It would save a lot of time and planning if a rover was even smart enough to take commands from Earth like "Turn 35 degrees and go 250 meters, avoiding obstacle".

Computer vision is notoriously unrobust. Stereo fusion (calculating a depth map from two camera views) has been around for decades, but it can be fooled by unusual textures or visibility features (something one camera sees but is hidden to the other). You definately want to believe input from cat whiskers or inclinometers more than you believe the vision algorithm, or the rover will end up driving off a cliff.

You're pushing the limits of robust AI algorithms to plan a path around an obstacle and still try to reach the target coordinates. And if anything hairy happens, it should stops and call Earth for help. Recognition and path planning tasks performed routinely by a rodent are well beyond what a super computer can do today.

The issue isn't processor speed, it is the primitive state of the art in AI algorithms. It's an unfortunately feature of academic AI culture to exagerate that state of the art, so be skeptical until you see a rover really doing what is promised on realistic outdoor terrain, not a white floor with colored cubes.
Go to the top of the page
 
+Quote Post
djellison
post Jun 16 2006, 09:01 AM
Post #74


Founder
****

Group: Chairman
Posts: 14344
Joined: 8-February 04
Member No.: 1



Don - have you seen the results of the Darpa challenge? It couldn't be any less lab-conditions - it was quite an achievment. Loads of the entries were complete failures - but a few were superb and completed a complex course over terrain both rough and smooth, with plenty of obstacles, totally unassisted.

Doug
Go to the top of the page
 
+Quote Post
ljk4-1
post Jun 16 2006, 02:09 PM
Post #75


Senior Member
****

Group: Members
Posts: 2454
Joined: 8-July 05
From: NGC 5907
Member No.: 430



Jim Bell said that during certain points of the day, especially at sunrise
and sunset, the Mars Rovers would sometimes refuse to move ahead.

Turns out they interpreted their shadows as pits in the ground and
did not want to fall into them. They had to be "told" that shadows
were okay to drive on.

About a decade ago, a robot car designed by the US military being
tested on a regular automobile road kept swerving over to the other
side of the lane for seemingly no reason.

Turned out that a row of trees had their shadows falling across the
road and the robot car interpreted them as obstacles and obeyed its
programming by trying to avoid them.

This does make one admire the abilities of what the brain can do
in such a compact package.


--------------------
"After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance.
I see that such intercourse long continued would make one thoroughly prosaic, hard,
and coarse. But the longest intercourse with Nature, though in her rudest moods, does
not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
indeed much harder than a rock. From hard, coarse, insensible men with whom I have
no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

- Henry David Thoreau, November 15, 1853

Go to the top of the page
 
+Quote Post

38 Pages V  « < 3 4 5 6 7 > » 
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 20th September 2021 - 10:27 PM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member.