7 ms·

and no word on how it moves. even bbc is going downhill :(

by gcb0 9y ago

mikekchar 9y ago
Here is an article straight from Jaxa: http://iss.jaxa.jp/en/kiboexp/news/170714_int_ball_en.html http://iss.jaxa.jp/en/kiboexp/news/170714_int_ball_en.html They also don't say, but they link to this article: http://www.kenkai.jaxa.jp/eng/research/electrical/triaxial.html http://www.kenkai.jaxa.jp/eng/research/electrical/triaxial.h... which has a lot more technical detail. Unfortunately I don't have time to dig deeper, but hopefully it will help you search a bit better.
TeMPOraL 9y ago
It seems to be rotating via reaction wheels (via this[0]). I haven't yet figured out how it translates, though. EDIT: if you have gravity available, the video on that site illustrates a clever way to use those reaction wheels to move around by tumbling. EDIT2: "for maneuvering around in space there are twelve electric micro-fans or μFans"[1]. The SE thread has a screenshot of a video which shows the placement of those fans. EDIT3: Full video about the Int-Ball[2]. -- [0] - http://www.kenkai.jaxa.jp/eng/research/electrical/triaxial.html http://www.kenkai.jaxa.jp/eng/research/electrical/triaxial.h... [1] - https://space.stackexchange.com/questions/22324/how-does-jaxas-int-ball-manage-airflow-to-optimally-navigate-inside-the-iss https://space.stackexchange.com/questions/22324/how-does-jax... [2] - https://www.youtube.com/watch?v=ZtIARUS7Lqc&feature=youtu.be&t=40 https://www.youtube.com/watch?v=ZtIARUS7Lqc&feature=youtu.be...
- venning 9y ago
  From a related video: the reaction wheels spin up while keeping total angular momentum at zero, then apply a rapid (magnetic) brake to transfer the momentum to the body (from the wheels). I'm assuming if you do that precisely enough (and in three dimensions), you can generate linear movement. EDIT: I'm probably very wrong about the movement. EDIT: The video: https://youtu.be/n_6p-1J551Y https://youtu.be/n_6p-1J551Y
  - lordvon 9y ago
    how does conservation of linear momentum apply? edit: this question was asked when the parent comment claimed that this machine could "generate linear momentum" from the wheels.
    - venning 9y ago
      Imagine holding up a bicycle in the air from the midpoint. Now spin both wheels in opposite directions. No movement. Now apply one brake. Now you have movement. Now do that in three dimensions with precision and you have this thing. Conservation of momentum applies when there are "no external forces", which wouldn't be the case here when you apply the brake. EDIT: Yeah, my apologies. I didn't mean to write "momentum".
      - averagewall 9y ago
        The brake is an internal force though (the force and its reaction both act on the bicycle). The whole unit's only external forces are from the fans so that's all it can use to translate. That and bumping into things.
        TeMPOraL 9y ago
        > That and bumping into things. Come to think of it - in air you're constantly bumping into things - air molecules. I think it could technically be possible to steer in zero-g within an atmosphere by pure rotation (e.g. consider that a fast-spinning object is kind of a (crappy) fan).
        LeifCarrotson 9y ago
        And, in fact, that's what this device does. It uses an array of 12 small rotating fans placed around its surface to push jets of air and move itself from place to place.
        9y ago
- DougWebb 9y ago
  The use of fans is disappointing; that means it can't go outside. My first thought when seeing it is that it'd be great for doing external inspections, and could even have its own private little airlock to get in and out. Maybe they could make a version with ionic thrusters, that stays outside all of the time. It could have a 'nest' where it parks and refuels when not in use.
  - ceejayoz 9y ago
    I'd imagine that'll come in time. Easier to start inside, where you can pick it up if it runs out of batteries or glitches out. Less chance of poking a hole in something critical, as well.
  - dysfunction 9y ago
    Ion thrusters have tiny acceleration, which is why they're best on deep space missions (slow and steady wins the race). I wouldn't think they'd be practical for this type of thing, which you'd want to go one or a few kilometers per hour over distances of tens of meters.
  - frandroid 9y ago
    You could just set rails or clotheslines outside the station for an external drone camera to travel along.
    - krisoft 9y ago
      Or maybe not whole rails, but just fixtures the drone could grab onto. You could supply the drone with power and control signals through the fixtures, and the drone could kinda travel everywhere by just grabbing onto a nearby fixture, then releasing the previous one. Wouldn't that be great? /s
      - seniorsassycat 9y ago
        Canadarm2, the robotic arm on the International Space Station, does this. https://en.wikipedia.org/wiki/Mobile_Servicing_System#Canadarm2 https://en.wikipedia.org/wiki/Mobile_Servicing_System#Canada...
- munificent 9y ago
  Here's a video that shows the actual thing moving in zero gravity: https://www.youtube.com/watch?v=PntNBeJuRFQ https://www.youtube.com/watch?v=PntNBeJuRFQ
nashashmi 9y ago
I was looking for the same thing. It has got a motor inside and uses some kind of momentum to rotate. Another motor makes it go forward, but at a snail's pace.
- TeMPOraL 9y ago
  It has 3 motors for 3-axis reaction wheel set (for rotation), and 12 fans to move around.
monort 9y ago
According to their press release it has 12 propellers (推進用ファン): http://issstream.tksc.jaxa.jp/iss2/press/170714_intball.pdf http://issstream.tksc.jaxa.jp/iss2/press/170714_intball.pdf
tlrobinson 9y ago
I also found this quote amusing: "The drone can float in a zero-gravity environment"
eeZah7Ux 9y ago
Forgive the stupid question: what makes the use of reaction wheels and fans preferred over fans installed at different angles? Energy efficiency or fan reliability perhaps?
- Retric 9y ago
  Precision and speed, reaction wheels can go from start, rotate you one degree and then stop all motion. With fans your going to end up constantly correcting because you never hit zero rotation.
  - eeZah7Ux 9y ago
    The robot is exposed to the station airflow so it has to adjust constantly anyways.
    - Retric 9y ago
      While non zero, the spherical shape and minimal ISS airflow generally makes this a non issue. You can use those reaction wheels to calibrate very precise adjustments over time, you can also just bump into something to get rid of excess rotation. Note, space telescopes effectively use both approaches.
- venning 9y ago
  It may also minimize the impact all of that moving air has on everything else in the station. Without gravity, fans blowing your things around could get annoying.
- wubbfindel 9y ago
  Being able to operate with no atmosphere (e.g. outside of the ISS) would be an advantage I suppose.
  - eeZah7Ux 9y ago
    Yet, the translation movements are done using fans. Perhaps it's a prototype and future version will operate outside.
fspeech 9y ago
Any reason why it couldn't use air jet to create linear motion? It is floating in air after all. Okay, just saw EDIT2 of TeMPOraL: https://news.ycombinator.com/item?id=14795857 https://news.ycombinator.com/item?id=14795857, it appears to move around using micro fans.

and no word on how it moves. even bbc is going downhill :(

by gcb0 9y ago

and no word on how it moves. even bbc is going downhill :(

Here is an article straight from Jaxa: http://iss.jaxa.jp/en/kiboexp/news/170714_int_ball_en.html http://iss.jaxa.jp/en/kiboexp/news/170714_int_ball_en.html They also don't say, but they link to this article: http://www.kenkai.jaxa.jp/eng/research/electrical/triaxial.html http://www.kenkai.jaxa.jp/eng/research/electrical/triaxial.h... which has a lot more technical detail. Unfortunately I don't have time to dig deeper, but hopefully it will help you search a bit better.

TeMPOraL 9y ago

It seems to be rotating via reaction wheels (via this[0]). I haven't yet figured out how it translates, though. EDIT: if you have gravity available, the video on that site illustrates a clever way to use those reaction wheels to move around by tumbling. EDIT2: "for maneuvering around in space there are twelve electric micro-fans or μFans"[1]. The SE thread has a screenshot of a video which shows the placement of those fans. EDIT3: Full video about the Int-Ball[2]. -- [0] - http://www.kenkai.jaxa.jp/eng/research/electrical/triaxial.html http://www.kenkai.jaxa.jp/eng/research/electrical/triaxial.h... [1] - https://space.stackexchange.com/questions/22324/how-does-jaxas-int-ball-manage-airflow-to-optimally-navigate-inside-the-iss https://space.stackexchange.com/questions/22324/how-does-jax... [2] - https://www.youtube.com/watch?v=ZtIARUS7Lqc&feature=youtu.be&t=40 https://www.youtube.com/watch?v=ZtIARUS7Lqc&feature=youtu.be...

venning 9y ago
From a related video: the reaction wheels spin up while keeping total angular momentum at zero, then apply a rapid (magnetic) brake to transfer the momentum to the body (from the wheels). I'm assuming if you do that precisely enough (and in three dimensions), you can generate linear movement. EDIT: I'm probably very wrong about the movement. EDIT: The video: https://youtu.be/n_6p-1J551Y https://youtu.be/n_6p-1J551Y
- lordvon 9y ago
  how does conservation of linear momentum apply? edit: this question was asked when the parent comment claimed that this machine could "generate linear momentum" from the wheels.
  - venning 9y ago
    Imagine holding up a bicycle in the air from the midpoint. Now spin both wheels in opposite directions. No movement. Now apply one brake. Now you have movement. Now do that in three dimensions with precision and you have this thing. Conservation of momentum applies when there are "no external forces", which wouldn't be the case here when you apply the brake. EDIT: Yeah, my apologies. I didn't mean to write "momentum".
    - averagewall 9y ago
      The brake is an internal force though (the force and its reaction both act on the bicycle). The whole unit's only external forces are from the fans so that's all it can use to translate. That and bumping into things.
      - TeMPOraL 9y ago
        > That and bumping into things. Come to think of it - in air you're constantly bumping into things - air molecules. I think it could technically be possible to steer in zero-g within an atmosphere by pure rotation (e.g. consider that a fast-spinning object is kind of a (crappy) fan).
        LeifCarrotson 9y ago
        And, in fact, that's what this device does. It uses an array of 12 small rotating fans placed around its surface to push jets of air and move itself from place to place.
        9y ago
DougWebb 9y ago
The use of fans is disappointing; that means it can't go outside. My first thought when seeing it is that it'd be great for doing external inspections, and could even have its own private little airlock to get in and out. Maybe they could make a version with ionic thrusters, that stays outside all of the time. It could have a 'nest' where it parks and refuels when not in use.
- ceejayoz 9y ago
  I'd imagine that'll come in time. Easier to start inside, where you can pick it up if it runs out of batteries or glitches out. Less chance of poking a hole in something critical, as well.
- dysfunction 9y ago
  Ion thrusters have tiny acceleration, which is why they're best on deep space missions (slow and steady wins the race). I wouldn't think they'd be practical for this type of thing, which you'd want to go one or a few kilometers per hour over distances of tens of meters.
- frandroid 9y ago
  You could just set rails or clotheslines outside the station for an external drone camera to travel along.
  - krisoft 9y ago
    Or maybe not whole rails, but just fixtures the drone could grab onto. You could supply the drone with power and control signals through the fixtures, and the drone could kinda travel everywhere by just grabbing onto a nearby fixture, then releasing the previous one. Wouldn't that be great? /s
    - seniorsassycat 9y ago
      Canadarm2, the robotic arm on the International Space Station, does this. https://en.wikipedia.org/wiki/Mobile_Servicing_System#Canadarm2 https://en.wikipedia.org/wiki/Mobile_Servicing_System#Canada...
munificent 9y ago
Here's a video that shows the actual thing moving in zero gravity: https://www.youtube.com/watch?v=PntNBeJuRFQ https://www.youtube.com/watch?v=PntNBeJuRFQ

nashashmi 9y ago

I was looking for the same thing. It has got a motor inside and uses some kind of momentum to rotate. Another motor makes it go forward, but at a snail's pace.

TeMPOraL 9y ago
It has 3 motors for 3-axis reaction wheel set (for rotation), and 12 fans to move around.

monort 9y ago

According to their press release it has 12 propellers (推進用ファン): http://issstream.tksc.jaxa.jp/iss2/press/170714_intball.pdf http://issstream.tksc.jaxa.jp/iss2/press/170714_intball.pdf

tlrobinson 9y ago

I also found this quote amusing: "The drone can float in a zero-gravity environment"

eeZah7Ux 9y ago

Forgive the stupid question: what makes the use of reaction wheels and fans preferred over fans installed at different angles? Energy efficiency or fan reliability perhaps?

Retric 9y ago
Precision and speed, reaction wheels can go from start, rotate you one degree and then stop all motion. With fans your going to end up constantly correcting because you never hit zero rotation.
- eeZah7Ux 9y ago
  The robot is exposed to the station airflow so it has to adjust constantly anyways.
  - Retric 9y ago
    While non zero, the spherical shape and minimal ISS airflow generally makes this a non issue. You can use those reaction wheels to calibrate very precise adjustments over time, you can also just bump into something to get rid of excess rotation. Note, space telescopes effectively use both approaches.
venning 9y ago
It may also minimize the impact all of that moving air has on everything else in the station. Without gravity, fans blowing your things around could get annoying.
wubbfindel 9y ago
Being able to operate with no atmosphere (e.g. outside of the ISS) would be an advantage I suppose.
- eeZah7Ux 9y ago
  Yet, the translation movements are done using fans. Perhaps it's a prototype and future version will operate outside.

fspeech 9y ago

Any reason why it couldn't use air jet to create linear motion? It is floating in air after all. Okay, just saw EDIT2 of TeMPOraL: https://news.ycombinator.com/item?id=14795857 https://news.ycombinator.com/item?id=14795857, it appears to move around using micro fans.