There is noise in robotics applications too, but apparently it still
works fine. According to the specs for the board I linked, it fires 8
pulses for each measurement, presumably to obtain several data points to
eliminate false reflections and noise. I just figured it would make an
interesting test.
As you, I am personally also favoring the capacitive method. Can be
constructed to work as anti-slosh baffle(s) at same time.
/H
------ Original Message ------
From: "Bruno Berger" <mailinglists@xxxxxx>
To: arocket@xxxxxxxxxxxxx
Sent: 9/16/2015 12:24:41 PM
Subject: [AR] Re: Ultrasonic fluid level monitoring
On rockets you have lots of other ultrasonic sources (Engine, incoming
pressurant, airflow around the airframe ect.). I am pretty sure this
interferes with the sensor. Keep also in mind that speed of sound
depends on the root of the temperature of the gas (and that changes
quite during operation in a tank).
My favorites are capacitive sensors (you can use the tanks inner surface
as one of the capacitor plates), resistors on the tank wall and the
RADAR looks also good to me (depending on the dielectric constant of the
fluid. But at least hydrocarbons are ok and probably LOX as well).
Bruno
"At that time [1909] the chief engineer was almost always the chief test pilot as well. That had the fortunate result of eliminating poor engineering early in aviation" (Igor Sikorsky)
