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Re: [Paparazzi-devel] strange behaviour in lisa m

From: Refik Sever
Subject: Re: [Paparazzi-devel] strange behaviour in lisa m
Date: Mon, 9 Sep 2013 00:20:18 +0300

Hi Felix,


Thank you for your recommendations.


We upload the code using USB cable. We turn off the 12V battery, and the autopilot takes its voltage from USB. Therefore, some of the peripherals (Airspeed sensor etc) are off during upload. Then, we remove the USB cable and turn on the battery.  We always make a power cycle after upload. Sometimes, it does not behave normal, and we need to upload it again.


"in order to make checks for low or critical batter voltage easier and more robust we added this to the electrical subsystem in master."


Did you also add it to stable branch?


Best regards,




From: address@hidden [mailto:address@hidden On Behalf Of Felix Ruess
Sent: Sunday, September 8, 2013 10:57 PM
To: Paparazzi devel list
Subject: Re: [Paparazzi-devel] strange behaviour in lisa m


Hi Refik,


in order to make checks for low or critical batter voltage easier and more robust we added this to the electrical subsystem in master.

It will automatically set the electrical.bat_low and electrical.bat_critical flags when the voltage drops below BAT_LOW or BAT_CRITIC for a certain amount of time to avoid setting this on very short voltage drops.

You can use it in your flight plans for example as follows:

<exception cond="electrical.bat_low && !electrical.bat_critical" deroute="Standby"/>

<exception cond="electrical.bat_critical" deroute="land"/>


About the behavior right after upload new code to the autopilot: depending on how you upload the code (jtag, usb, etc..) it sometimes seems to not correctly reset everything (probably related to external peripherals?).

To be safe you can power cycle once to make sure everything starts up as intended.

@Piotr: do you know why this sometimes happens?


Cheers, Felix


On Sun, Sep 8, 2013 at 9:27 PM, Refik Sever <address@hidden> wrote:

Dear all,

We are using Lisa-M and we had a lot of successful flights. We wanted to go to a slightly farther distance. And we wanted to turn back if the voltage drops below 11V, or the datalink is lost for 180s. We added this line to the perfectly working airframe file:

<exception cond="datalink_time > 180 || (11.0 > PowerVoltage())" deroute="Standby"/>

But, the upload time of the code to Lisa was rather longer. And it behaved very slowly, the PFD screen changed very slowly. I could not moved the ailerons in Auto1 from RC, but it worked in Manual mode. We thought that, it measured the power voltage below 11V at startup, although it was over 12V. And we thought that, it was very slow because of the exception conditon. That was the only change in the airframe file.

Then, we added a variable named "ready" and set it to TRUE only when it first goes to Holding Point. Therefore, we quaranteed that it will not enter exception at power up:

<exception cond="datalink_time > 180 || (11.0 > PowerVoltage() && ready)" deroute="Standby"/>

It was good on the ground. The voltage was 12V. Everything seemed normal. But in takeoff, it behaved again very slowly. It had a loop and crashed.

In the replay, voltage was decrease to 11.2V but it went to Standby before it reached normal altitude. I think that the telemetry rate was low and missed that the power voltage decreased below 11V. But the autopilot entered to exception.

Is this behaviour (slowly reacting) occurs due to this exception condition? Does it freezes the autopilot? What can we do to prevent it?

Sometimes, we upload the code to Lisa M but it does not behave normally. Then, we re-upload the same code and everything becomes good. Is there a possibility that it uploads incorrectly? Why does it take longer time for some uploads? Doesn't it need to be constant?

I am sending the logs. I can also send the video recorded from the wing.



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