Subject:
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Re: GPS Reality?
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Newsgroups:
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lugnet.robotics
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Date:
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Mon, 11 Apr 2005 14:31:01 GMT
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Viewed:
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1228 times
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I'm a lurker, so apologies for jumping into your conversation.
I believe iRobot patented an interesting system last year called
'Polaris' or something similar which used the principle of navigating by
the stars to position a robot platform in an indoor environment.
Several dots of light (presumably IR) were projected onto the ceiling of
a room by a base station and mobile robotic platform in the environment
then used the observed parallex differences in viewing the dots from
different locations in the room to position themselves.
At least that's what I remember, probably wrong. An intriging idea none
the less though.
Allen.
danny staple wrote:
> A solution I suggested on the DPRG list was that if radio telemetry is
> being sent to and from the robot, then to have each robot with a
> clearly identifiable dot- rather like a police car - on the top. You
> could then have a camera covering the arena, and a desktop machine
> with visual processing software to work out the relative position of
> the dot, then communicate this back to the bot with the telemetry.
> However - this would only work in a very small space.
>
> Also - it would limit the choice of colours, as Lego colours tend to
> be very saturated colours, which are what this technique normally uses
> to find stuff. We are back to visual processing now - but at least it
> is now taken off the bots.
>
> Another idea is to have an infra-red emmiter on the robot, and (in a
> relatively unobstructed arena), sensors along the two horizontal axes.
> Each robot broadcasts a different ID, and the arena systems use the ID
> along with the sensors getting the clearest signal to send the robot a
> radio signal back with the ID of the sensors or full coords. The
> problem is that this approach needs a lot of sensors - its off the top
> of my head, and I get the feeling dealing with multiple IDs while
> doing strength comparisons from that many sensors may not be
> particularly easy. This could be reversed with IR LEDs each
> broadcasting a narrow beam coordinate along the side and front/back of
> the arena- and the robot using this to infer its position by
> differentiating the strongest signals. If the robot had a wide sensor,
> while the beams were quite tight - that might actually work. But again
> - you need a lot of beams, and a relatively unobscured arena.
>
> Yet another is to use three Ultra-sound beacons again, but modulating
> the ultra-sonic signals to include a time code - I get the feeling
> that this may be too hard - although it is closest in function to what
> you actually get from the GPS satellites.
>
> The thing is - it is worth taking for granted that most of the
> solutions will require specialist equipment in the arena - which
> considering GPS relies on the satellites - is not an unreasonable
> requirement.
>
> Danny
> --
> http://orionrobots.co.uk - Build Robots
>
> On Apr 11, 2005 2:14 PM, PeterBalch <lego-robotics@crynwr.com> wrote:
>
>
> > > three sonar beacons,
> > > which are broadcast a radio ping, and then transmit each of their
> > >
> > >
> > signals.
> >
> >
> > > The bot controller than uses the time difference between the request
> > >
> > >
> > radio
> >
> >
> > > ping, and the sonar reply to work out its position.
> > >
> > >
> > So the robot works out it's best guess from the three intersecting circles.
> >
> > Of course, the radio signal is not strictly neccessary. Beacon A broadcasts
> > it's beep. Beacon B hears A, waits a fixed delay then broadcasts it's beep.
> > Beacon C hears A, waits a longer delay time then broadcasts it's beep. Etc.
> > The robot hears the beeps (in order A, B, C, ... because the delays are
> > long enough). It works out it's best guess from the intersecting
> > hyperbolae.
> >
> >
> >
> > > JB: I've worked with a number of "solutions" but none of them are
> > > anything I'd recommend.
> > >
> > >
> > What's the best you've see so far?
> >
> > Peter
> >
> >
>
>
>
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Message has 1 Reply:
 | | Re[2]: GPS Reality?
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| Apologies for my rather inconsistent memory, it was Evolution Robotics rather than iRobot. Still a good idea though in my opinion. (URL) ever ordered a dev. kit? Allen. Monday, April 11, 2005, 3:31:01 PM, you wrote: AF> I'm a lurker, so apologies (...) (20 years ago, 11-Apr-05, to lugnet.robotics)
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Message is in Reply To:
| | Re: GPS Reality?
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| A solution I suggested on the DPRG list was that if radio telemetry is being sent to and from the robot, then to have each robot with a clearly identifiable dot- rather like a police car - on the top. You could then have a camera covering the arena, (...) (20 years ago, 11-Apr-05, to lugnet.robotics)
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