Dear all, 

After an earlier post (12/OCT/2015) related to Pixhawk, I present you now the results of a first trial with ArduBoat. First, we constructed a simple platform and did some trials with RC in a swimming pool. 


This week we did some tests in a lake near Asuncion, Paraguay. The catamaran performed well in Manual Mode (has good steering and has enough propulsion to move in windy conditions).



The problem is when we put it in Automatic Mode. It seems that the waypoints are not read by the Pixhawk and when in Auto Mode is directed to the same place (is likely to be directed to a waypoint other than the loaded, however, in the LOGS, we didn't find any Waypoint, and less the ones introduced by ourselves).

When reading out the logs, it seems that our planned waypoints were not taken into account by the Pixhawk. We would be very grateful if anyone of you could help us decipher why it behaves this way. For this reason I attached my Logs.

Here are some images from the Mission Planer with the Waypoints loaded and the Path that took the Boat.


The Red Points were the Launching Points.

For the first trials we launched the platform from the A point and it didn't went to the waypoints, but, instead, went to B point. In a second attempt, we launched it from the B point and it went to the C point. So we decided to launch the platform from another location D to see to which direction it would navigate. In this launch, the platform went on a straight line to location E. Then we decided to do a second launch from the F point, initially directing the platform to different direction than E point, but surprisingly it turned itself in order to head again towards location E. It seemed to us like the platform was heading to an ´imaginary´ point somewhere far away!

Apparently the Pixhawk has only recorded the GPS points when he was Armed. Is that how it works? I should only load the Waypoints when he's Armed?

All recommendations will be very welcome.

Thanks in advance.

Best regards.

Esteban Caligaris




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    • @David Boulanger

      Thanks for your time.


      Esteban Caligaris

    • Hello everybody.

      So, my friend was analyzing my Logs and he found this about the Yaw:

      AHR2 - Yaw:

      3702912139?profile=originalATT - Yaw:

      3702912236?profile=originalEKF1 - Yaw:

      3702911978?profile=originalAnd the HDop Logs from the GPS are these:

      3702912262?profile=originalCould have been these the reasons of my troubles?

      Thanks for all.


      Esteban Caligaris

    • Admin


      Before you start a lot of analysis of your operating data, I suggest that you determine if your servo is even steering correctly in the Auto Mode as I suggested above.

      Looking at the Pixhawk steering output PWM signal, it was oscillating wildly on either side of the neutral (1500us) point.



    • Ok. Thanks David.

      These are my reading from the Accelerometers:







      Esteban Caligaris

    • they are good.  I'm shocked.


      David R. Boulanger

    • This is not caused by the waves.  Graph your accel x,y, and z axis vibrations on mission planner and post it.  The reason it may not be going to waypoints properly may be a combination of vibrations, your compass and a high HDOP.


      David R. Boulanger

    • @Tom,

      you are exactly right.

      What would I suggest is to implement servo controlled rudder since large propulsion

      fan acts as a gyroscope effect affected large diameter rotating ring.

      Servo controlled rudder could greatly reduce gyroscope effect.

    • TCIII thank you very much.
      I'll bench testing to see what results I get.
      If anyone could think in a reason why, apparently, the waypoints are not loaded in the Pixhawk, it would be appreciated. The only reason I can think of is that the waypoints are not loaded for not being Armed. So here comes a basic question, what's the routine to follow in order to get the Pixhawk with ArduRover reading the Waypoints?


      Esteban Caligaris

    • I bought it from a reseller who claimed it was from 3D Robotics Store and it seems to be an original Pixhawk. I'll give it a try today and I'll update how everything goes.
      I, actually, loaded via 3DR Telemetry Radio, while was Unarmed, and it seems it haven't load the Waypoints by this way. And yes, I've clicked the Write WPs button and then have clicked the Read WPs button.

      My MIS_RESTART param is set at 0 = Resume Mission, acording to Mission Planner Software.

      Thanks for the feedback and I'll be updating my results of the bench test today.


      Esteban Caligaris

    • Estaban,

      What is your mission restart parameter set to?  Also, when you load the waypoints do you then read them to make sure they are right.  When you launched from A, depending what your waypoint radius is set at, It may have said, O.K. i'm at A time to go to B.  Then, if mission restart is set to pick up from the last waypoint, when you launched from B it would go to C and not A.


      David R. Boulanger

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