ArduRover - In R/C boat - high frequency rudder cycling - ArduBoat User Group

Hi,

I have ArduRover v2.49 with Mission Planner 1.3.28 running with a 3DR Pixhawk with 3DR telemetry in a model boat.

I have now successfully completed a few missions albeit over small distances. While on the face of it, everything looks perfect, the boat continually wobbles (twitches) and telemetry logs indicate high frequency rudder cycling.

The telemetry replay for the 3 minute mission is on :

http://youtu.be/SgPZQHQajRg

It looks very successful apart from the Ch1out values. This is the rudder.

The attached 'Rudder and ESC.jpg' shows mission output for both rudder and ESC (motor).
I had change to manual mode just before WP3 at about 10:46:40 to avoid a collision and that explains the ESC anomoly at that time. I realize I have to adjust (reduce) the desired cruise speed and that's not a problem. But the rudder activity is a concern.

The attached 'Rudder.jpg' shows a second by by second breakdown of rudder activity over a representative interval. This shows a 20 degree to port then a 20 degree to starboard almost every second. Hence the wobbles and twitches and probably why speed isn't rising.

I know this isn't a software or firmware issue - it's down to my own incompetence / unfamiliarity.

The final 'MP config.jpg' shows what is currently set. I'm sorry to be asking stupid questions, but is this the right screen to start modifying the rudder behavior ? Does anything look obviously wrong ? Or do you have any other advice or suggestions ?.

Thanks in advance for any suggestions, help, advice or pointers.

Tony

Rudder and ESC.jpg

Rudder.jpg

Mission_Planner_Config.jpg

Hi Thomas and thanks for the info.

Yes - 3DR Ublox GPS which is mounted on the 3DR pedestal for sat visibility and noise reduction.

I did level and calibrate the compass. In Mandatory Hardware -> Compass it shows Manual - Rotation_None. Although I have a Pixhawk it wont save that value and reverts to Rotation_None. Compass behaves impeccably and aligns to within a few degrees of my schoolboy compass. I dont know about accelerometer calibration but think this was done automatically by the compass setup wizard.

I'm worried that (like an idiot) I hurriedly changed a couple of default steering values at the pond last week and didn't record the previous values. So I have lost the defaults. Current values as requested are:

STEER2SRV_D 0.005

STEER2SRV_I 0.2

STEER2SRV_P 1

STEER2SRV_TCONST 0.75

STEER2SRV_MINISPD 0.5

STEER2SRV_IMAX 1500

Thanks for any advice and for your time.

Tony

Replies

- David Boulanger > Tony Holt June 2, 2015 at 11:12am
  
  Tony, I have a 18 lb. catamaran and the NAVL1 setting would cause it to weave in straight runs in auto when it was to low. I would think that every hull design would be different and I don't know if it needs to be raised or lowered. Your operating in a fluid environment and the corrections take time to effect your heading. Not like if you had tires on the ground and the turning would be immediate. It could be something else but just my first thought was try NAVL1.
  
  Regards,
  
  David R. Boulanger
- Tony Holt > David Boulanger June 2, 2015 at 11:19am
  
  Thanks David - Please don't interpret my response as ingratitude - I really appreciate your help and entirely agree about the fluid environment aspects - with dozens of factors. Thank you for sharing hard earned knowledge and I'm really grateful for the information. Thanks again. Tony
- David Boulanger > Tony Holt June 2, 2015 at 11:29am
  
  No ingratitude taken. Tom could probably look at your logs and give you better advice. All I meant with the fluid environment comment was your parameters may be very different from a rover that is on terra firma.
  
  Regards,
  
  David R. Boulanger
- Admin
  
  Thomas J Coyle III > Tony Holt June 2, 2015 at 11:09am
  
  @Tony,
  
  NAVL1_PERIOD and DAMPING affect straight line performance as well as turns.
  
  Are you using a 3DR GPS/Compass module?
  
  Did you level and calibrate the accelerometers?
  
  What are your values:
  
  STEER2SRV_D
  
  STEER2SRV_I
  
  STEER2SRV_P
  
  STEER2SRV_TCONST
  
  STEER2SRV_MINISPD
  
  STEER2SRV_IMAX
  
  Please provide tlogs and dataflash logs to help troubleshoot your issue.
  
  Regards,
  
  TCIII AVD
- Tony Holt > Thomas J Coyle III June 2, 2015 at 11:36am
  
  Hi Thomas and thanks for the info.
  
  Yes - 3DR Ublox GPS which is mounted on the 3DR pedestal for sat visibility and noise reduction.
  
  I did level and calibrate the compass. In Mandatory Hardware -> Compass it shows Manual - Rotation_None. Although I have a Pixhawk it wont save that value and reverts to Rotation_None. Compass behaves impeccably and aligns to within a few degrees of my schoolboy compass. I dont know about accelerometer calibration but think this was done automatically by the compass setup wizard.
  
  I'm worried that (like an idiot) I hurriedly changed a couple of default steering values at the pond last week and didn't record the previous values. So I have lost the defaults. Current values as requested are:
  
  STEER2SRV_D    0.005
  
  STEER2SRV_I     0.2
  
  STEER2SRV_P   1
  
  STEER2SRV_TCONST 0.75
  
  STEER2SRV_MINISPD 0.5
  
  STEER2SRV_IMAX 1500
  
  Thanks for any advice and for your time.
  
  Tony
- Admin
  
  Thomas J Coyle III > Tony Holt June 2, 2015 at 1:35pm
  
  @Tony,
  
  The accel calibration is not done by the compass setup wizard and is separately calibrated in the Setup Wizard.
  
  Try setting STEER2SRV_MINISPD 0.5 to 2.0 and play around with STEER2SRV_P.
  
  However, tlogs and dataflash logs of your boats operation with greatly help to troubleshoot your issue.
  
  Regards,
  
  TCIII AVD
- Tony Holt > Thomas J Coyle III June 3, 2015 at 4:17am
  
  Thanks for clarifying the accel calibration Thomas.
  
  Also for the STEER2SRV_MINISPD and STEER2SRV_P suggestions which I appreciate.
  
  For the sake of completeness I've attached the Tlog file as requested. Grant has the corresponding dataflash log.
  
  Thanks again
  
  Tony
  
  2015-05-31 10-25-43.tlog

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