Turn in place on manual mode with two motors

Posted by jean-luc on January 30, 2015 at 1:27pm

Hi all,

I just equiped one medium inflatable boat (3 meters lenght) with pixhawk and APM2.7.

The boat have two electrics motors and a capacity to turn in place with the RC (vtail mixage) connecting directly on the motors controller. if trottle stick at zero, steering stick completly right or left, one motor go fast forward and the other motor go fast backward.

Now, with the pixhawk module, when i want to turn in manual mode (trottle stick at zero, steering stick completly right or left), one motor go slowly forward and one motor go slowly backward.

If i move the trottle stick for more speed, the backward motor stop and only the forward motor go fast, not good for a real turn in place!

Is there one parameter for change that? i can't found.

Other think, in my advanced setting, i don't found the setting for serial port 4 and 5 configuration. Only the setting for the1, 2 and 3 serial port, it is normal on 2.47 apmrover firmware?

Thanks and regards.

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Replies

  • jean-luc February 2, 2015 at 9:43am
    Thomas,

    I have a Pixhawk, not an APM.
    And all my sticks are at 1500 on middle position.

    Regards,
    • Admin
      Thomas J Coyle III > jean-luc February 2, 2015 at 11:02am

      @jean-luc,

      I am at a loss as to the reason behind your turning issue. I have passed on to you everything I know about the differential steering without actually being there to troubleshoot with you.

      You are using the latest stable version v2.47?

      Regards,

      TCIII AVD

    • jean-luc > Thomas J Coyle III February 4, 2015 at 1:09pm

      Thanks a lot Thomas, yes it's the latest version V2.47.

      So i try to go on sea tomorow for the first test with the autopilot. (depending of the weather...)

      Another question:  the loiter or stabilize mode was effective or not on the apmrover? do you think we can use these mode like a DP (dynamic positioning) mode on real vessel?

      Regards,

    • Admin
      Thomas J Coyle III > jean-luc February 4, 2015 at 1:56pm

      @jean-luc,

      I have never tried the loiter or stabilize modes on my rovers due to the fact that they are specific to multicopters and planes.

      However Grant Morphett our Developer/Program is looking at a loiter mode for loitering at specific waypoints.

      Regards,

      TCIII AVD

  • Admin
    Thomas J Coyle III January 30, 2015 at 4:00pm

    @jean-luc,

    Are you using the elevator (pitch) joystick for the throttle channel and the aileron (roll) joystick for the steering channel?

    I have a skid steering RSV and have not experienced the problem you are describing with a pivot turn. If I want to go right the left motor goes to full speed and the right motor goes to full reverse.

    Regards,

    TCIII AVD

    • jean-luc > Thomas J Coyle III January 30, 2015 at 11:55pm

      Thomas,
      I make a serial cable to connect a second C-NAV GPS to the common serial plug 4&5 on pixhawk (i just use the port 4 RX/TX and GND) and when i want configure the setting for this port, i don't find this port in my firmware :/

      For the RC controls (DC16 jeti), i use the trottle stick for trottle and aileron stick for Roll, connect these RC output on the channel 1 and 3 of the PPM encoder module. Just cheat a little to connect the ppm module channel 3 on the RC output receiver channel 2.
      When i make the calibration, the roll and trottle bar are moving perfectly to 930 / 1990 and around 1500 for middle position.

      So, this monday i check again to find where is this serial 4 parameter.

      Have a good week-end.

    • Admin
      Thomas J Coyle III > jean-luc January 31, 2015 at 9:23am

      @Jean-luc,

      The Differential steering function expects the speed control (throttle) to be coming from the elevator (pitch) joystick. Maybe that is why you are having a problem?

      Here in the USA the throttle channel has no neutral position (1500us). Only the elevator and aileron joysticks have a spring return neutral position.

      Regards,

      TCIII AVD

    • jean-luc > Thomas J Coyle III February 2, 2015 at 8:58am

      Hi Thomas,

      I make a test with all joysticks and assignements possible, the result is alway the same:

      -if i place the trottle on middle position (neutral) and i turn the steering at full right or left the differential motors speed in only at 20% of capacity.

      -if i move the trottle full speed in same time with the steering full right or left, only one motor go full speed, the other motor stop or go very slowly in same direction.

      Normaly, without pixhawks module, if i place the trottle on middle position (neutral) and i turn the steering at full right or left the differential motors speed is at full capacity.

      So, i confirm my other problem, i don't have any serial port 4 and 5 parameters in my full parameters list. (see my list attached)

      Thanks a lot if you have another idea.

      regards,

      serial.JPG

      https://storage.ning.com/topology/rest/1.0/file/get/3702776626?profile=original
    • Developer
      Grant Morphett > jean-luc February 5, 2015 at 7:04pm

      Can you please post your logs.  tlog and flashlog's (.bin).  I'll have a look through them once posted.

      Thanks, Grant

    • jean-luc > Grant Morphett February 25, 2015 at 8:45am

      Hi Grant,

      Sorry for the response delay.

      I make the first test on water and after somes settings modifications, the boat comming to navigate fine.

      During the test i have a "bad compas healt" msg comming with a permanent lag, but i thinks the problem is comming from my ESC powering pinout.

      Now, i'm using the opto-isolated pinout of the ESC and powering the pixhawk only with his power module and USB port and it seems working good on these conditions.

      3702877136?profile=original3702877041?profile=original

      For my steering problem, please find attached the files requiered.

      Best regards

      Jean-luc

      2015-02-18 10-29-32.tlog

      2015-02-18 10-40-34.bin

This reply was deleted.