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

[Rich Grise]

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

 

[PeteS]

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

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

 

[Don Foreman]

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

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!

 

[YD]

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

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.

 

[joseph2k]

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

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

 

[Rich Grise]

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

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

Thanks!
Rich