Subject:
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Re: Household Positioning System Re: DGPS
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Thu, 11 May 2000 16:03:44 GMT
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Original-From:
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[FThompson9@aol]avoidspam[.com]
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Viewed:
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644 times
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> Cool idea. Do you have it working? Or do you have a schematic that is
> somewhat working? If so, I want to test out how accurate it will be. It
> will be fun to use the LED as landmarks in the building.
No design, just an idea. The way I see it, you put a "Head" on the top
of your robot. It has three sensors mounted for tilt and pan. The easiest
way I can see it is to use gear head stepper motors with a "Home" switch to
point the thing. The Handy board issues step and direction pulses out a
parallel port to a stepper controller chip. The tilt motor mounts to the
shaft of the pan motor. Ribbon cable runs from the fixet frame to the moving
stepper and the sensor set. Mounted to the shaft of the tilt motor is a box.
inside the box at one end is a group of four "remote control sensors."
These are available from lots of places (Radio shack, BGMicro). You give
them 5 volts and ground and they respond with a digital output "I see it."
These four outputs goto digital inputs on the handy board. When the robot
powers up, it homes the sensor switches to the home switches. When the robot
enters a room, it stops points the sensors at the angles it expects to see to
beacons (it has a guess of where it is in the room and a table of where the
beacons are supposed to be). If it finds the beacon there, it verifies the
beacons transmitted code. If it does not find the beacon, it does a square
spiral search from the starting location outward until it finds the beacon.
With the new beacon angles, it revises its pose estimate and proceeds to move
to its desired location. The speed of acquiring the beacon will be limited
by the longest "off" time in the beacons ID code. (That is you don't want to
skip a sampled location just because your sensor was looking at that spot
when the beacon was sending 0.) While the robot is moving, the image of the
beacon will drift off of one of the sensors, and the controller will need to
issue steps to the pan/tilt system to bring the beacon back onto that sensor.
This will help the robot "track" the sensor position. I suppose you could
get away with one sensor and constantly scan around the beacon location, but
this would slow your robot down, and four sensors will tell you if you have
drifted off the spot, or if the beacon is sending a 0.
Sorry for the length, but this is about all I can say on the topic right
now.
Pherd
Currently in Pensacola FL soon Hartford CT
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Message has 1 Reply:
 | | Re: Household Positioning System Re: DGPS
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| I see. Humm. May be I can really use this. OK, if I put a few IR LED with ID at different locations in the room, and put them at the same height as the robot sensor so I don't need to worry about tilt angle. If I put the sensor fixed on the robot, (...) (24 years ago, 12-May-00, to lugnet.robotics.handyboard)
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