Tank Rover Settings

Good Afternoon,

I have a tank and regular car APM 2.6 set up.  The car is working well doing my grid patters, the tank on the other hand, has gone from weaving all over but hitting the way-points, to having seizures or a dance party and randomly driving into things. 

  • I have my Sabertooth 2 x 25 set up in RC Mode, Exponential response, Mixing mode.  The APM is NOT in skid steer mode.  
  • The compass is calibrated correctly. 
  • Manual mode is working pretty well.(I think i may need a new RC transmitter though)

My question is how can I adjust the settings to have the tank, do 90 and 180 degree turns on a dime.

I've been trying to find the balance of:

  • STEER2SRV_P 
  • TURN_MAX_G  
  • NAVL1_PERIOD  
  • SPEED_TURN_GAIN 
  • CRUISE_SPEED 
  • CRUISE_THROTTLE 

and to correct for weaving but still have a tight turn.

  • STEER2SRV_P 
  • STEER2SRV_D 
  • STEER2SRV_TCONST

 

I'm following http://rover.ardupilot.com/wiki/tuning-steering-and-navigation-for-... for guidance. 

One side questions. Since i'm using an external compass and GPS does the APM 2.6 still have face forward? 

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Replies

    • Thanks for your reply.
      You connected to channel 1 and 2? Not 1 and 3?
      I will upload 2.45 tomorrow and see how it works.
    • Admin

      @Sebastian,

      The servo output connections depend on your R/C receiver channel outputs and the RCMAP parameters for PITCH, ROLL, THROTTLE, and YAW.

      Regards,

      TCIII AVD

    • Admin

      Hi Sebastian,

      The differential (skid) steering function in the stable ArduRover v2.46 release is broken.

      Please try and use either v2.45 or v2.44 which can be found here: Link

      You only need to set SKID_STEER_OUT to 1 if you are using the elevator and aileron joysticks for throttle and steering.

      I set up a Wild Thumper 6WD rover using a Pixhawk, loaded with stable v2.45, with a Spektrum Remote Receiver and a Sabertooth 2X25 ESC in the dual controller mode (no mixing).

      I used the elevator joystick for the throttle (forwards/backwards) and the aileron joystick for steering right and left. I mated the Spektrum remote Receiver with a Spektrum DX7 and used Pixhawk servo output channel 1 for the left motor and servo output channel 2 for the right motor.

      I do not remember how the RCMAP was setup for the PITCH and ROLL when using the Spektrum Remote Receiver.

      Regards,

      TCIII AVD  

  • Developer

    Hi Joseph,

    first let me say i dont have a Sabertooth ESC in my wild thumper setup but im right now facing the same issue as you have described.

    Driving through a programmed mission works but occasionally i see the weaving and dance party behavior.

    I thought its because im using a external compass (HMC5983 instead the usual HMC5883) on my PX4-v1 but have yet to investigate if it is the cause.
        

    Just wanted to chime in and say that were working on this, i will try to capture a log the next days and will work with Tridge to get to the bottom of this although it might take a few weeks because of the OBC Tridge is facing right now.

    Im using 2 brushed  motor ESC's in my Thumper setup and so im using it with skidsteer functionallity.

    As you have written its correct that the pivot turning only works while using SKID_STEER_OUT = 1.
        
    As Tom noted it might be worth a try to configure the sabertooth ESC for skid steering, maybe that can help but im not sure.
        
    The issue you wrote about HOLD mode was not reproduceable for me when i tested it on the bench yesterday, i have yet to do a test in the field.
    But usually the rover goes into HOLD if failsafe gots triggered because of lost RC-Transmitter link or weak GPS reception.
        
    Will keep you posted but suggest you try the new release that was just published this night by Tridge and try the sabertooth skid steer settings.

    http://diydrones.com/profiles/blogs/apm-rover-2-46-released

    Cheers
    Linus

  • Admin

    @Joseph,

    In the Full Parameter List there is a parameter called PIVOT_TURN_ANGLE. The default is 30 deg, but you can try 90 deg for a right angle pivot turn. I do not know about 180 deg.

    Unless you want to change the AHRS orientation (AHRS_ORIENTATION) of the APM, it should face forward.

    Regards,

    TCIII ArduRover2 Developer

    • Tom,

      FYI It appears the newest version of mission planner doesn't have the pivot turn angle option.

    • Admin

      @Joseph,

      What version of ArduRover2 firmware are you using?

      I do not believe that it is in ArduRover2 stable version v2.45.

      You need to use the v2.46 beta2 found here: Link

      Regards,

      TCIII ArduRover2 Developer

    • Tom,

      I finally got a chance to load the beta software, but now i cannot get into Auto mode.  When i flip over to it, the apm just goes into hold mode, with good gps and all else was good, and unchanged.  Just the firmware version.

    • Admin

      @Joseph,

      I have been using the version 2.46 beta 2 firmware with my rovers and have not had a problem with the Auto Mode. I presently do not have a skid steering rover so I have no way to try and duplicate your setup.

      Going to the HOLD Mode when initiating the Auto Mode usually occurs with loss of the R/C signal or the completion of a mission (last waypoint completed).

      Do you have a mission loaded when trying to initiate the Auto Mode?

      Regards,

      TCIII Autonomous Vehicle Developer 

    • I do have a mission loaded.  I ran the mission, uploaded the new firmware, then tried to run the mission again, but it would not switch out of hold mode.  The settings are correct for that input, it should be in auto mode.  I went back a firmware version and it worked again.

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