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It took 11 hours because of locomotion method of the Kilobots - they use vibration to move. Without at least looking at the paper, and probably studying it in d

It took 11 hours because of locomotion method of the Kilobots - they use vibration to move. Without at least looking at the paper, and probably studying it in depth, it would be hard to determine how good the algorithm is. It is definitely nothing revolutionary, however bot movement is not externally controlled. They figure out their own relative positioning and where they need to go. Moreover they do that only based on short range led communications. So they communicate with small number of other bots at the same time (I think one, but I am not 100% sure), as opposed to lets say using central router to communicate all at the same time. TL:DR Sensors, movement systems, and precision are shit on purpose, so important part that distributed algorithm actually worked.

deleted 12y ago
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tomp 12y ago
I'm pretty sure it's externally controlled to some extent. Otherwise, how would they know what kind of shape to build, and even more importantly, how to scale it - to do that, you have to know the total number of robots, something which cannot be discovered locally.
- scott_s 12y ago
  The article answered those questions: First, all the robots are put together in an unformed blob and are given an image of the desired shape to be built. Four specially programmed seed robots are then added to the edge of the group, marking the position and orientation of the shape. These seed robots emit a message that propagates to each robot in the blob and allows them to know how “far” away from the seed they are and their relative coordinates. Robots on the edge of the blob then follow the edge until they reach the desired location in the shape that is growing in successive layers from the seed. The algorithm had to account for unreliable robots that are pushed out of their desired location or block other robots performing their functions. Nagpal’s team overcame this challenge by implementing strategies that allowed robots to rely on their neighbours to cooperatively monitor for faults. They also avoided relying too heavily on exact positioning within the shape boundaries.
  - tomp 12y ago
    Maybe I'm not understanding the quote correctly, but I see no explanation of how they figure out the correct scale (i.e. the size of a shape - obviously, with 4096 robots, they could make the shape twice as big).
    - scott_s 12y ago
      I was pointing out that it's not externally controlled. If you want a full understanding of the algorithm, you'll probably need to read the paper. The supplementary material and the full paper go into this in detail. The supplementary material is a pdf, which I can email to you if you want to see it.

deleted 12y ago

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tomp 12y ago

I'm pretty sure it's externally controlled to some extent. Otherwise, how would they know what kind of shape to build, and even more importantly, how to scale it - to do that, you have to know the total number of robots, something which cannot be discovered locally.

scott_s 12y ago
The article answered those questions: First, all the robots are put together in an unformed blob and are given an image of the desired shape to be built. Four specially programmed seed robots are then added to the edge of the group, marking the position and orientation of the shape. These seed robots emit a message that propagates to each robot in the blob and allows them to know how “far” away from the seed they are and their relative coordinates. Robots on the edge of the blob then follow the edge until they reach the desired location in the shape that is growing in successive layers from the seed. The algorithm had to account for unreliable robots that are pushed out of their desired location or block other robots performing their functions. Nagpal’s team overcame this challenge by implementing strategies that allowed robots to rely on their neighbours to cooperatively monitor for faults. They also avoided relying too heavily on exact positioning within the shape boundaries.
- tomp 12y ago
  Maybe I'm not understanding the quote correctly, but I see no explanation of how they figure out the correct scale (i.e. the size of a shape - obviously, with 4096 robots, they could make the shape twice as big).
  - scott_s 12y ago
    I was pointing out that it's not externally controlled. If you want a full understanding of the algorithm, you'll probably need to read the paper. The supplementary material and the full paper go into this in detail. The supplementary material is a pdf, which I can email to you if you want to see it.