Tracked or Wheeled?

As far as I remember the article about a Venus robot you found a few weeks ago proposed a robot the article called "thumb" - that word seems to mean a robot without intelligence but having sensors only which transmit their data to a satellite having intelligence.

I am talking about a robot which has sensors only and the abrasion tool etc. but no CPU etc.

Do I understand and use wrong the word "thumb"?



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

EDIT:Jjust this moment I checked the article and recognized that I remebered wrong - the correct word is "dumb" - I am talking about a dumb rover.

Ok, well it seems a bit silly to put wheels or tracks on something which can be lifted around by [insert favorite flying mars explorer here] anyway. I could see the balloon acting to complicate the balance of the rover though, that might be a bad situation. Particularly if the balloon is being pulled about by erratic breezes. E.g. in a dust devil.

Hmmm ... ok I'm trying to think of a mars-exploring concept that avoids the whole wheeled/tracked approach to surface mobility. Being a biologist I'm sort of stuck in the paths laid down by evolutionary answers to the problem of ground mobility. Currently I like the model supplied by spiders. Ever watched one of those manuevering through long grass? 3D poetry in motion. A robot explorer that could move like that would have great mass dispersal characteristics. Could fold up quite small for those restricted volume payloads. Picking its way through rockfields, up slopes, across gaps. Jumping? Why not (well ok, perhaps we don't want to shake the mass spectrometer around too much). Of course having an infinitely strong cable and grappling hook helps too ...

http://www.defensetech.org/archives/001436.html

However, for planetary exploration robots like that we might be waiting a good long while. I guess were stuck with wheels or tracks for the interim.

DKH

I assume he means "dumb" as in not possessing a control computer of its own... I assume...

No problem - I simply was imagining the ARCHIMEDES-balloon of the Mars Society moving around at Mars and thought that it could carry sensors too to investigate the ground. It would have the problem then that it can't be kept at points worth to stay at them longer. So it would have to have an anchor to stick into the ground and to remove that anchor off the ground again later.

I remebered the rovers then and the problem Opportunity had. I tried to optimize all this then. A balloon larger than ARCHIMEDES could rteplace the skycrane I thought of in an earlier post in this thread. I don't know if balllons can be controled and steered in the martian atmosphere like in the earthian - and so I preferred to control and steer all by wheels and tracks but to free them from the burden of the weight by keeping it lifted very very slightly by the balloon..

It was just a thought only.



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

It seems that tracks might be heading towards Mars after all if this vehicle being developed in the Antartic is anything to go by.

http://www.space.com/astronotes/astronotes.html

OK. Now you have me thinking about a robotic amoeba. Low center of gravity. Good, close position for surface analysis. Very low sensitivity to wind …

NEWS FLASH: NASA LANDS SLIME MOLD PROBE ON MARS

Sorry for the double-post, but apparently we have an answer:
http://edition.cnn.com/2005/TECH/06/23/antarctica.explorer/

Andy beat you to it a few posts earlier ...

DKH

NGAAH! I fail. Guess it would help if I looked a bit more carefully at the page he'd linked to...

Simply because I was thinking about the idea for quite another purpose already:

What about using Hovercraft-technology for a rover? The air cushion could use CO2. Initially dry ice/CO2 may be carried from Earth and heated by laser. At night and in winter it may be repalced by martian dry ice/Co2. Perhaps the polar regions are the best regions to apply it.

Tracks still will be required to move such a rover - may the air cushion keep the tracks clean?

Would it work to ingest CO2, compress or sqezze ram it and to push it out as a jet for propulsion - like airplanes do? The atmosphere will be too thin to propell a rover by propellers I suppose.



Dipl.-Volkswirt (Bdvb) Augustin (Political Economist)

Hovercraft only really work on a very smooth surface -- that's the biggest reason that they haven't done much.

They go across the channel too when the weather is bad and there are much waves and they start on land where there is grass growing and over the beaches - some of the landscapes to be seen on photos sent by the two rovers look as if they are similar to the surroundings where I have seen Hovercrafts moving.

Of course they wouldn't go up hills and into craters - but they may manage that "Purgatory" dune.

What about using a larger and more dumb carrier rover and one or more smaller intelligent investigation rovers? The carrier rover could be a Hovercraft while the investigation rovers could be like Spirit and Opportunity and go where the Hovercraft can't go. What about improvements of Hovercrafts for martian purposes? What might be possible?



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

Hovercraft are pretty inefficient and waste a lot of energy blowing all that air around, using them on Mars would not be a good idea.

I think that they have now stopped using them accross the channel because they were expensive to run and prone to breakdown (the skirt which trapped the air kept tearing). While its true they went out in bad weather conditions I think they were only operated when waves of were 50cm or less in height. Remember that the cross channel hovercraft were 50M in length weighing 200 tons, any craft transported to Mars would be much smaller and hence not able to handle bumps as big.

They are also not very easy to steer, a group of us built a single man hovercraft when we were apprentices in the mid-eighties and after only one afternoon doing "trials" in a field it required a complete rebuild of its bow due to a misunderstanding with a tree. Driving one of these remotely would be impossible.

PS: you can buy a cross channel hovercraft secondhand if want but you'll need another fortune to keep it running. Bloody noisy to ride in though, you have to shout if you want to talk to the person next to you, lucky there was all that duty free booze to take your mind off it.

http://www.vessels4sale.com/high_speed/ ... _speed.htm

Yeah, we played with a mini-hovercraft powered by an electric leaf blower in my physics class. Couldn't hear a thing and the only good thing about steering was that you could spin like a top and gyro-stabilize yourself. It's a good thing none of us were prone to motion sickness. Of course, it was a lot of fun playing hockey with our lab instructor....