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Isn't it a bummer when you're bidding a project, and it's proprietary?

Just thinking about ultrasonic control for a sort of robot/not a robot:

Say, I've got a steerable carriage of some kind, with the two drive motors, and differential steering. Lots of robots have that sort of drive; a lot of robots also have ultrasonic pingers.

But I'm thinking minimal smarts here:

Suppose you've got this carriage, and instead of a self-directed robot, you want a follower. I'm thinking an array of transducers (TD) on the unit, and one on the operator.

Would a phased array be hard to do, with ultrasonic TDs?

Like, with four transducers, you could compare the phases and figure out both the distance and direction to the leader's pinger.

IOW:

------------- v----Four transducers in a row | follower |< ---- |< | |< >| leader |< | | ----- -------------

The wavefront will arrive at slightly different times, depending on the position of the source.

Anybody wanna toss around ideas? :-)

Cheers! Rich

Reply to
Rich Grise
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That's the basis of the airborne radio direction finders I used to work on (not radar) :)

One of the problems is the effective signal velocity varies so much - a reference may be desirable. A transducer in a small box that has the same atmospheric conditions as the outside where the return distance is known precisely, for instance.

Cheers

PeteS

Reply to
PeteS

Might work with an electrostatic TD ala Polaroid. Assuming that this is in air rather than water or some other medium, the phase behavior of piezo TD's as fn of freq, temp, production tolerances, phase of the moon, etc would make things rather dicey.

Interesting problem!

Reply to
Don Foreman

Late at night, by candle light, Rich Grise penned this immortal opus:

The phase differences may not give enough resolution. And, as Don said, may suffer from too much variation between units.

How about using directional TDs with some overlap of the lobes and aiming for equal amplitude? May still have some angular off-set but that can be trimmed out.

A pair of wide-lobed TD's (each side of the thing) for acquisition and a narrow-lobed (in front) for lock-in.

- YD.

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Reply to
YD

In general, getting direction from passive sensor / evaluator systems is not difficult; getting distance normally requires some kind of round trip (active) sensor / evaluator.

--
 JosephKK
 Gegen dummheit kampfen die Gotter Selbst, vergebens.  
  --Schiller
Reply to
joseph2k

Actually, the leader (just a little pinger) and follower are part of a set, so a transponder would probably be pretty easy.

Thanks! Rich

Reply to
Rich Grise

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