Google Lunar XPrize

[kyle]

Lunar night: Could we have some type of switch that is controlled by Sunlight? I think we are probably best to power down during that time. also couldn't we avoid lunar night all together just by moving away from it?

Powering the vehicle: What happens when our Fuel Supply runs out? we can't just send it up more. i think that electricity would be a much better method for powering it. besides we will probably want to pause and observe places quite often. We can control different motors to run at different times. with electricity you have more control of the vehicle. Also if it gets cold are fuels just going to freeze? I really think relying on the Suns power will make the robot last longer.

Finding the big ditches: How about electric arms the cover 4 to 6 points around it. you can have probes come out and check how far off level the ground is. just by hitting the rock. It would almost map the surface of the moon that way.

btw this is probably the closest thing i've done to this, Super mileage car competition. Our major problem for that was funding and time. we placed 6 but each of the top 5 had about double the miles per gallon than what we had

more specifically


after working on this car's engine there is too much that can go wrong with combustion.

[Jonathan]

Do you guys really want to do it?

I can't guarantee anything now, but I can at least keep helping if nothing terrible happens to me.

Jonathan - Find out our options for imaging. The realtime feed is webcam-quality, to give an idea what we're after. Check the rules, and then survey hardware options. We need to know all options, regardless of whether or not they're pc-compatible.

I'll see what I can do. Keep in mind that most of my experience is in taking pictures. More specifically, I've played with someone's still camera and understand photographic concepts. I currently lack knowledge about the exact details and how they compare to those of a typical video camera, and where to start with a custom solution.

[Jonathan]

Lunar night: Could we have some type of switch that is controlled by Sunlight? I think we are probably best to power down during that time. also couldn't we avoid lunar night all together just by moving away from it?

It's not a race in that sense! We're talking about (very roughly) 15 km/h or 10 mph at the 'equator'. At a 'pole' that's less, but you don't want to stay near a pole and still drive around like crazy just to follow the Sun, do you?

During the night it might be possible to keep very limited hardware running on our side of the Moon, by catching Earthshine. When the Earth is dark you're catching direct sunlight, and when there's no sunlight the Earth will provide some. Lunar eclipses are short enough to not pose a problem.

Finding the big ditches: How about electric arms the cover 4 to 6 points around it. you can have probes come out and check how far off level the ground is. just by hitting the rock. It would almost map the surface of the moon that way.

Less moving parts is better. There are other ways to obtain the same information and more.

[Concord]

i'd like to jump
onboard

my mechanical skills are superior to
any coding i've done

i've got LEGO NXT
which like RCX
but with blue tooth
and more sensors
its much more
potential as a
testing vehicle

GPS seems to me
a nice alternative

a friend of mine
has finished a
superior GPS algorithm
more precise
i can get more details
Lucifer's algorithm sounds sound
as well

[Lucifer]

We have to brave the lunar night if we want to win the prize for braving the lunar night. It's a bonus prize, the base mission is the imagery discussed and the 500m distance.

Concord: I don't think I actually know you, but I have a job for you if you want it. It's more research. I have temporarily forgotten it, though, I'll post back when I remember it. (Haven't started on a plan yet, but the information I wanted would be needed sometime)

[kyle]

We need a way to communicate our Ideas and research efficiently
what about shared Google Docs? i used it for a group presentation and multiple people could work on that at the same time. what other options do we have.

[Lucifer]

I like Google docs a lot. We can also start up an irc channel in freenode, but iirc jonathan isn't much of an irc user. You are, though, but we can clutter #armagetron if we want. Better yet, we can work in #luke-jrisanasshat .

I'm willing to use google docs for document writing and stuff, but I like wikis a lot better. I'm not in a position to throw up a wiki, though, so I'll be happy to work with google docs in the meantime. Does everybody here have an account there?

Concord: I remember what the job was. Talk to your buddy and find out how gps works and whether or not the signals can be received on the moon. If he's willing to give us his code under an open source license, I'd be willing to look at it..

[kyle]

Cooling this robot will be another issue. they make you think about the cold but never mention the Heat. the moons min and max temperatures are -233/123 °C. 123°C is something we will have to watch out for. we need to make sure all of our chips are not overheated. to be honest I am more worried about the Heat then the cold. just a little bit of something else that needs research.

[Jonathan]

Not sure about Google Docs, never used it. I do have an account, so it's probably quick to set up.

I'm not a fan of IRC but I guess I could get it working. I'm also not a fan of Luke, but I haven't had problems with him either.

GPS: would be nice if someone knew the actual precision you could expect on the Moon. I think that if the signal is strong enough, the worst problem is that all satellites take up a small part of the sky. Problems in practice:
- No standard hardware that can manage the distances.
- Forced Earthbound interpretation (no problem if hardware gives 'raw' access to data), where they can again screw up. If it does work and with good precision, you still need access to the precise time to get a good estimate on the Moon.
- Need to know the Moon's location with high precision. If you already know where you are (e.g. you just landed, know your landing site, and didn't move yet) you could potentially adapt for a bit.

Heat: start by reflecting as much significant heat-producing radiation as possible. And other damaging radiation at the same time.

[Lucifer]

I think there's a pretty good chance the GPS satellites are earth-oriented to a point where the signals aren't even sent out towards the moon. So that's really the first thing we need to know about it. Secondly, I consider GPS or any position-finding method to be a check on our dead reckoning. The possible exception here is if we put a gps-like transmitter on the lander, the rover can find its position relative to the lander. That may be the most flexible option, but it only works until we're out of range of the lander's transmitter.

I've been considering the idea of grabbing as much heat during the day and storing it, and then slowly releasing it at night. Since the max temperature is over the boiling point of water, we could put a little water tank and then pump the resulting really hot water (pressurized, I suppose, else it boils) through passages inside the rover to warm it. The power requirements on such a pump may be very small, particularly if we use the fact that it's pressurized to reduce the power requirement, because then we just need to open/close valves. So the question there is how much water do we need to take to store enough heat?

I've started a Lunar Surface Conditions document on google docs so we can collect our notes. If you send me your email address via some private channel, I'll invite you to collaborate on it.

For wheeled vehicles, I'm seeing several configurations to think about. There's the standard 4-wheel configuration. We could do a two-wheel configuration where the wheels are both on the line of travel, like a motorcycle. We could do a two-wheel configuration where the wheels share an axis of rotation. We could do a three-wheel configuration where the drive wheels share an axis of rotation and we put third wheel to make a triangle. In both of those last cases we probably want to have two motors and use the torque difference between them to steer.

Treads have a number of advantages over wheels, though. For one thing, you can cross small ditches with treads that you can't cross with wheels because the wheels would get stuck. There are disadvantages, though.

I'm interested in the two wheel configuration where the wheels share the axis of rotation. Then we hang the rest of the rover hardware between the two wheels. We could also hang hardware on the outside, provided the thing is balanced. We could then put a series of spikes that can swing outward to dig in when more friction is needed, such as going up a steep slope. Tipping sideways is the only tipping we have to worry about, because it's not possible in that configuration to tip forward and be unable to recover.

I guess we need to test each configuration in a simulator and see what's the best.

[Jonathan]

I think there's a pretty good chance the GPS satellites are earth-oriented to a point where the signals aren't even sent out towards the moon.

They might be oriented to the Sun, necessitating omnidirectional transmission (or constantly changing direction). There are also a lot of them, so there's a good chance some will give you a signal because you're in a similar direction (the orbit is fairly high; Earth won't block it too soon).

So that's really the first thing we need to know about it. Secondly, I consider GPS or any position-finding method to be a check on our dead reckoning.

There are two main scales:

- Global: where you are on the Moon, though not down to the meter. GPS or celestial navigation. If we go with celestial navigation and take a photo at the required detail/panorama resolution, we have about 500 m per pixel if I'm not mistaken.
- Local: finding short-term routes, avoiding obstacles, etc. Dead reckoning and direct sensing.

There should be a good amount of overlap between the scales where different methods work well, and the information at the global scale should be good enough.

How much precision do we really need? What has been used before?

The possible exception here is if we put a gps-like transmitter on the lander, the rover can find its position relative to the lander. That may be the most flexible option, but it only works until we're out of range of the lander's transmitter.

GPS works by checking distances to known reference points and deriving a position. A single point doesn't provide much information. Shouldn't be too hard to sense direction though, but you could still be anywhere on a circle. The sky can fix that ambiguity. Since we're not going to stay nearby, is additional precision in the landing area worth it?

For wheeled vehicles, I'm seeing several configurations to think about. There's the standard 4-wheel configuration. We could do a two-wheel configuration where the wheels are both on the line of travel, like a motorcycle. We could do a two-wheel configuration where the wheels share an axis of rotation. We could do a three-wheel configuration where the drive wheels share an axis of rotation and we put third wheel to make a triangle. In both of those last cases we probably want to have two motors and use the torque difference between them to steer.

Better to simply be stable if you want to last. Also consider the consequences of something happening to a wheel for some reason.

I'm interested in the two wheel configuration where the wheels share the axis of rotation. Then we hang the rest of the rover hardware between the two wheels. We could also hang hardware on the outside, provided the thing is balanced. We could then put a series of spikes that can swing outward to dig in when more friction is needed, such as going up a steep slope. Tipping sideways is the only tipping we have to worry about, because it's not possible in that configuration to tip forward and be unable to recover.

You do need some solar panel area. Maybe huge wheels then. But what if you get stuck? Just rotate like crazy in between the heavy wheels?

[QUARG]

This is a company not far from my house that i have been looking into for a while. They manufactur and repair low cost robots and develpment platforms. This might give you some interesting directions in the design and quite possibly they may have software available.

http://www.robotshop.ca/home/index.html

This are my favorite designs for best mobility and stability. They also have quite a bit of suface area for sensors and tools.

http://www.robotshop.ca/home/products/r ... h2-kt.html

http://www.robotshop.ca/home/products/r ... combo.html

http://www.robotshop.ca/home/products/r ... t-kit.html

http://www.robotshop.ca/home/products/r ... m-kit.html

In the past i have considered many bot designs but have always thought that reversible one to be the best.(meaning it can run upside down.)

[Tank Program]

I've read so much I've forgotten 90% of my comments.

If you're going to look at stellar navigation, don't stick a mirror on the base station.

Also, I'd be worried about steam pressure if you tried to store it for reuse. It'd be better to have something dense to absorb heat and re-emit it during the night. (Like concrete or brick.)

I think either a walker, wheeled, or treaded. would be best. If you could use massive treads or wheels that were larger than the vehicle, it could potentially fall down an incline and flip without any major problems other than the stability of on board systems. It would all have to work both ways up is the only downside. A low RPM high torque drive mechanism would also be best. Considering the lower gravity, a smaller scale should be easily achieved compared to earth.

Er, this is a yes that I'm interested in participating, but I don't know how much I can really do. At the very least I can toss out the uninformed opinion and idea. Since I'm studying Civil Engineering, I can probably offer informed opinions on things like the structural design of the base station and bits of the rover. (Like the maximum force felt due to launch, you don't really need a factor of 2 there. That's over engineering. 1.3-1.5 is much more reasonable. Things like that.)

[Concord]

i'll write normally. . .

Our use of the GPS that is in place now looks unlikely, given the moons distance from the Earth (385,000 km average) it would be a very weak signal if we could pick one up at all. For GPS's current purposes the 24 satellites maintain a orbit approximately 19,000 km from the Earth. The US military can get about a 20 m range of error, but this is do to the atmosphere, humidity and on ground interference, (buildings, mountains etc.). Supposing that we could get the 4 signals on the moon, we would have a much more accuracy. By my estimates it would be within 5 m. My friend's new algorithm reduces the error on earth to just about 5 meters, and on the moon we'd get about 2-3 m.

The problem is that we just couldn't get 4 signals that far away.

So if we want to use GPS, and right now I don't, we'd have to set up our own system. This would include a signal coming from the base station, our satellite, and two other points on the moon. I do not think this is out of reach because we'd be dealing with just a small area to cover. But it might entail a lot of unnecessary work.


GPS works by receiving signals from 3 satellites and finding the intersection point of all 3 and the earth's sphere, the intersection point gives the 2D location of the receiver. So for the 3D information we need, we'd need 4 spheres/signals+moon's sphere.

Celestial navagation is looking like a better option to me, and a short term video+ultrasonic composition of the terrain. Use the colors from the video and mash it with the depths of the ultrasonic to create a description of the short term terrain ahead for the rover.

[QUARG]

What if we were to deploy 3 nodes/emitters from orbit before hand around the work area in precise locations so as to be able to triangulate the rovers location.
As for the heat exchanger i found this, though i dont know what size the components would be.
http://www.gsaresources.com/heat.htm
http://www.engineeringtoolbox.com/sensi ... _1217.html
I know from personal experience that storing energy over long periods is very difficult in extreme temperatures, though im not sure that there would be much of a probleme for elctronic components to survive at 125deg C.