5 ms·

The whole point of implementing A* on Curiosity was to give it some navigation autonomy. The time delay in getting sensor data back to earth, coming up with a m

The whole point of implementing A* on Curiosity was to give it some navigation autonomy. The time delay in getting sensor data back to earth, coming up with a motion plan, then sending the plan back to be executed imposes tight limits on how fast the rover can drive, what kinds of terrain it can cover, and ultimately how much science can be done. Local autonomy for basic "go over to than weird-looking rock" tasks is a major improvement.

gorgoiler 6y ago
You could A* your way around the whole planet by using an Earth based computation but only if you knew where every rock was. There must be some equation of motion in space robots that combines terrain difficulty, robot speed, round trip time to Earth, and how far ahead you’d need to be able to see. Curiosity moves about as fast as a Roomba. The ping is (min/avg/max) 10’/24’/40’. Ergo, it needs to be able to see X yards ahead of itself to plan A* from Earth, requiring a camera boom Y feet tall producing images with Z megapixels of resolution. I wonder what X, Y and Z are.
- throwaway189262 6y ago
  Does curiosity really move that fast? Roomba is maybe 2 mph. I thought curiosity was closer to 0.1 mph
  - JohnJamesRambo 6y ago
    His or her estimate seems wildly off. I had the same response because my Roomba moves fast! Some quick googling says- Curiosity max speed equals 0.08699 mph. Roomba equals a foot per second which is 0.682 mph. Off by about 7.82x.
    - gorgoiler 6y ago
      Thanks: my estimate of Roomba slowness was way off. I’ve only ever seen them on TV. I remember once hearing that Curiosity, flat out, could do 1km a day.
      - throwaway189262 6y ago
        Random but I highly recommend the new "mapping" type roombas. Best thing I bought all year.
- cpgxiii 6y ago
  Some very rough numbers, if you want plans valid until you see the results and travel at a good speed: - You want a travel speed of 0.5 m/s - Worst-case round trip time from command to result is 40 minutes, or 2400 seconds - Max distance covered is 1200 meters - Assume you can drive over any rock 10cm or less in size (the rover can do better, but at a reduced speed) So you need to scan an area 1200m x 1200m, with range accuracy of, say, +/-5cm. Forget the camera boom height, or the time it might take to scan and process, there's no sensor that will give you that kind of accuracy. The stereo baseline would be huge, and leave you entirely at the mercy of whatever texture or not a given part of the martian surface has to offer. LIDAR is OK if you definition of "long range sensing" is larger objects at 200m. The time cost for shipping back all the raw data for processing would kill performance as well, and if you wanted to process it locally the compute requirements would be just as high as doing the planning locally as well. Onboard, or at least much closer,compute is the only way forward in autonomy. Honestly, the best bet on improving local compute would be to send a robot bulldozer, some C4, a rack full of milspec servers, and a big RTG. Blow a nice crater, push the servers to the bottom, and bury them in dirt for shielding. If you get really lucky, you could find some old cave or lava tube.
- scoopertrooper 6y ago
  That's more or less what they used to do with Sojourner, only with humans setting out the way points rather than A* . It never managed to get more than 10 meters from its lander though, I assume this was partly driven by the limitations on a human's patience in operating a slow vehicle with 28 minute feedback loop. One drawback of the remote A* approach is that you end up using more energy as the rover would have to be constantly communicating with its onboard antenna. Its relay satellites are only in range for a limited period each day. Fine grained maneuvers (like drive around that big rock to get to this small rock) would also prove difficult because of likely errors in the rover's inertial-navigation system. https://en.wikipedia.org/wiki/Sojourner_(rover) https://en.wikipedia.org/wiki/Sojourner_(rover)
publicola1990 6y ago
With what kind of processing power did the recent Change'5 probe did the autonomous docking manoeuvre in lunar orbit.. Also it seems to be doing sometype of image processing to identify a suitable landing spot and guiding on to that point.

gorgoiler 6y ago

You could A* your way around the whole planet by using an Earth based computation but only if you knew where every rock was. There must be some equation of motion in space robots that combines terrain difficulty, robot speed, round trip time to Earth, and how far ahead you’d need to be able to see. Curiosity moves about as fast as a Roomba. The ping is (min/avg/max) 10’/24’/40’. Ergo, it needs to be able to see X yards ahead of itself to plan A* from Earth, requiring a camera boom Y feet tall producing images with Z megapixels of resolution. I wonder what X, Y and Z are.

throwaway189262 6y ago
Does curiosity really move that fast? Roomba is maybe 2 mph. I thought curiosity was closer to 0.1 mph
- JohnJamesRambo 6y ago
  His or her estimate seems wildly off. I had the same response because my Roomba moves fast! Some quick googling says- Curiosity max speed equals 0.08699 mph. Roomba equals a foot per second which is 0.682 mph. Off by about 7.82x.
  - gorgoiler 6y ago
    Thanks: my estimate of Roomba slowness was way off. I’ve only ever seen them on TV. I remember once hearing that Curiosity, flat out, could do 1km a day.
    - throwaway189262 6y ago
      Random but I highly recommend the new "mapping" type roombas. Best thing I bought all year.
cpgxiii 6y ago
Some very rough numbers, if you want plans valid until you see the results and travel at a good speed: - You want a travel speed of 0.5 m/s - Worst-case round trip time from command to result is 40 minutes, or 2400 seconds - Max distance covered is 1200 meters - Assume you can drive over any rock 10cm or less in size (the rover can do better, but at a reduced speed) So you need to scan an area 1200m x 1200m, with range accuracy of, say, +/-5cm. Forget the camera boom height, or the time it might take to scan and process, there's no sensor that will give you that kind of accuracy. The stereo baseline would be huge, and leave you entirely at the mercy of whatever texture or not a given part of the martian surface has to offer. LIDAR is OK if you definition of "long range sensing" is larger objects at 200m. The time cost for shipping back all the raw data for processing would kill performance as well, and if you wanted to process it locally the compute requirements would be just as high as doing the planning locally as well. Onboard, or at least much closer,compute is the only way forward in autonomy. Honestly, the best bet on improving local compute would be to send a robot bulldozer, some C4, a rack full of milspec servers, and a big RTG. Blow a nice crater, push the servers to the bottom, and bury them in dirt for shielding. If you get really lucky, you could find some old cave or lava tube.
scoopertrooper 6y ago
That's more or less what they used to do with Sojourner, only with humans setting out the way points rather than A* . It never managed to get more than 10 meters from its lander though, I assume this was partly driven by the limitations on a human's patience in operating a slow vehicle with 28 minute feedback loop. One drawback of the remote A* approach is that you end up using more energy as the rover would have to be constantly communicating with its onboard antenna. Its relay satellites are only in range for a limited period each day. Fine grained maneuvers (like drive around that big rock to get to this small rock) would also prove difficult because of likely errors in the rover's inertial-navigation system. https://en.wikipedia.org/wiki/Sojourner_(rover) https://en.wikipedia.org/wiki/Sojourner_(rover)

publicola1990 6y ago

With what kind of processing power did the recent Change'5 probe did the autonomous docking manoeuvre in lunar orbit.. Also it seems to be doing sometype of image processing to identify a suitable landing spot and guiding on to that point.