Re: [Paparazzi-devel] Interference in flight Umarim lite 2.0

[Joseph Muhlhausen]

Hi Martin, thanks a lot for your help

this now sound like there is an issue with the RC receiver rather then
the servos. Correcting my last email: All grounds should be connected at
one point near the battery ground (like in a star). No parts should be
chained.

Where is the receiver ground connected?

RX, Xbee, GPS and now servos get ground from Umarim

ESC gets ground from the battery

Umarim gets ground from the battery

I am assuming this is OK and close to a star pattern. 

Paparazzi detects that the RC signal is bad and goes to home mode -
which is auto2. Have you tuned the aircraft in auto2 mode?

No I haven't setup AUTO 2 and HOME does not seem to be working properly, unless the GPS suffers from interference too. The simulation works very well for both HOME and AUTO2

From what you say there seems to be a relation between the ESC/motor
with full throttle and the receiver. Can you replace any of the parts?

I graphed yesterday's flight and the current pic and RC (short) signal loss are clearly correlated. Unfortunately I have only one TX (Graupner mx 16 HoTT 2.4ghz) and one RX (Graupner GR16 HoTT)

I tested other options. Adding Toroids between RX -- Umarim and Servos -- Umarim seem to clean the signal a lot. OK is now 100% green and servos don't make hissing noise when neutral. Will this work in flight... I am not sure, but it's an improvement.

Something that may be important, the +5V for the servos is still coming from the ESC.

Joseph

Date: Sun, 17 Feb 2013 08:44:35 +0100
From: Martin Mueller <address@hidden>
To: address@hidden
Subject: Re: [Paparazzi-devel] Interference in flight Umarim lite 2.0
Message-ID: <address@hidden>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Hi Joseph,

> I have tried running the motor with propeller on a bench. After a good
> run, when close to my metal door, the servos don't respond instantly to
> the radio and have glitches. i also noticed that when this happens, the
> OK radio indicator  in the GCS is half green half orange .

this now sound like there is an issue with the RC receiver rather then
the servos. Correcting my last email: All grounds should be connected at
one point near the battery ground (like in a star). No parts should be
chained.

Where is the receiver ground connected?

> I connected the servos to the umarim ground but didn't notice any change
> in my bench test (no flight). i then grounded the motor mount and added
> aluminium connected to the ground around the RX - Umarim cable section
> touching the battery wires. This improved my bench test, I do not see
> any glitches and the OK button is now 90% green.
>
> I went to fly and it went much better. In MANUAL I don't seem to have
> issues but I didn't go full throttle after take off, however in AUTO1, I
> still have glitches as the HOME mode kicks in and the plane goes down in
> a spiral.

 From what you say there seems to be a relation between the ESC/motor
with full throttle and the receiver. Can you replace any of the parts?
Paparazzi detects that the RC signal is bad and goes to home mode -
which is auto2. Have you tuned the aircraft in auto2 mode?

Martin

>
> Joseph
>
>
>     Hi Joseph,
>
>      > My plane flies great and is properly set up for AUTO1. However,
>     during
>      > the last two flights I could only control the plane
>     intermittently.  As
>      > soon as I would start throttle again I would lose control of the
>     plane.
>      >
>      > On the ground everything works fine including range test.
>      >
>      > All wires are twisted but none are shielded.
>      >
>      > Grounding:
>      > -ESC and Umarim share the same ground from the battery supply
>      > -ESC's BEC seem to have common ground (measures 0 V between Umarim
>      > ground and BEC ground)
>      > -RX and Xbee get the ground from Umarim
>      > -Servos get +5V and ground from ESC's BEC
>      > -No ground on motor or motor plate
>      >
>      > I am not sure where to start, if anyone has had a similar issue and
>      > found a fix that would help me a lot.
>
>     sounds like a ground issue. Between the Umarim and the servos ground
>     line is the battery -> ESC path. If you run the engine you will have a
>     current in that path that creates a voltage that disturbs the servo
>     signals. Try connecting the servos ground directly to the Umarim.
>
>     If that helps maybe the "Large Aircraft Connection Diagram" picture in
>     the Wiki needs an update.
>
>     Martin
>
>
>
>
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