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ArduRover User Group

Dedicated to the exchange of useful information between members using the Arduino or other families of processors for autonomous rovers.

Members: 441
Latest Activity: 4 hours ago

Before Posting an Issue

Hi All,

Before posting an issue or a problem in the ArduRover Discussion Forum, please check the wiki table of contents, review the firmware release notes in the subforum, and search that subforum for existing answers to your question. Help avoid duplicate threads by finding other members with the same issue and their solution.

When formulating your post, use a descriptive title such as "rover will not navigate to waypoints in the Auto mode" (not "HELP!" or "Problem").

Please include the following information to help diagnose your query:

  • Describe the problem you are having. What is the expected verses the observed behavior?
  • Provide hardware information such as the brand and version of your autopilot, GPS, radio, and compass, as well as any other pertinent details about your rover setup.
  • What version of the APM: ArdurRover2 firmware version are you running?
  • For navigation issues, provide your tlog and/or dataflash log. Click here for instructions on retrieving a dataflash log.

TCIII

Discussion Forum

Connecting non-3DR GPS

Started by Joe Dvorak. Last reply by Matthew Reimer 4 hours ago. 17 Replies

I have a Pixhawk system with all the standard 3DR peripherals (telemetry radio, GPS). I need to replace the 3DR GPS with another GPS unit so that I can conduct some tests with higher accuracy. I have…Continue

Tags: APM:Rover, GPS

Apm Rover in tractor setup.

Started by Matthew Reimer. Last reply by Matthew Reimer 16 hours ago. 39 Replies

I want to use pixhawk with the apm rover firmware to operate an agricultural tractor. I need to set up my tractor as an rc vehicle.  My plan is as follows: any feedback I can get is appreciated.  I…Continue

How to Install Dual Sonars on a Pixhawk

Started by Thomas J Coyle III. Last reply by jon c 17 hours ago. 28 Replies

Hi All,I just completed installing dual Maxbotix MB1240 sonars on one of my Pixhawk equipped rovers.Since the sonars were from an APM equipped rover they already had single pair shielded cables…Continue

Tags: install, Pixhawk, dual, sonar

Contributing to giving sight to AV's

Started by RoboBill. Last reply by Gary McCray May 21. 64 Replies

Hello everyone,I'm trying to design and build an "open source" radar system. The premise is that while we have the hacked Neato and the RoboPeak system, I've not found anything for outdoor use. So…Continue

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Comment by Antonie Kruger on March 3, 2014 at 1:57am

@Thomas - sorry, I missed the important questions.

I tried to use the skid steer implementation on the APM2. I installed 2.45 again after a complete erase and reset.

I activated the skidoutput, but left the skidinput as disabled and disabled the skid mixing on the Wild Thumper controller board. So the WT Controller takes Left and Right input and APM should give Left and Right output mixed from 2 channel receiver input. I re-checked my wiring twice and still had strange results. My rover starts to run at about 50 to 60%. All wheels with some direction change when moving the sticks. Yes, it was in manual mode.

I'm using a 6P uBlox chip to get the best possible results position wise. I use the rover under open skies and always have 6+ sats. I have applied the declination, so it should not be a hassle. It makes sense though that at startup and slow speeds the weaving is more because of a short GPS baseline - would it not be prudent to rely more on the mag at this point?

When the weather clears up I'll head out for some tuning, thanks for your help. If I have a thunderbolt of brilliance and get this sorted, I send you the final settings for the next noob.

Comment by Antonie Kruger on March 3, 2014 at 1:45am

@Thomas - I hear you : "For those of you with Pixhawk equipped rovers, the Pixhawk code with the EKF function can be found here: Pixhawk firmware with EKF Set AHRS_EKF_USE to 1 to enable."

The problem with this is that the PixHawk pricing => African country GDP. So replacing any of the APM's at this time whilst the $ and OPEC are killing our R, we'll have to be content with APM. I think Gary might have the only PixHawk in RSA. What I do find odd is that the sum of the parts is less than 25% of the price of the whole (Stone in the bush).

I was unable to go out this morning - farmer friendly weather has moved in.

Comment by Thiago Gabriel on March 2, 2014 at 10:16pm

I'm Thiago Gabriel, Mechatronic Engineer. I'm working with a Masters of Mechanical Engineering, where I have to apply a ardupilot automodelismo Firehammer Duratrax DTX. My question is: have some step by step (tutorial) how to ride a rover? Another question is also how I can connect the optical flow in ardupilot 2.6? 
I was watching a tutorial where one connected the optical flow in ardupilot 2.6, but he cut a contact there. That's right or have another way to connect? 
I would also like to know if you communicate with the GPS ardupilot NTRIP network. 
I'm waiting and I thank you for your attention


Admin
Comment by Thomas J Coyle III on March 2, 2014 at 3:54pm

@Michael,

That would be a question for Tridge as he is more familiar with how the operating parameters interact with one another.

My rover has a turning circle value of 1.3 m, but I have found that a value of 1.0 is optimal.

A PERIOD of 6 - 7 is the best for my Slash rover that has a fast and tight steering system.  NAVL1_PERIOD values of less than 8 can improve steering response, but can cause dithering in the steering for fast steering vehicles. Less maneuverable rovers using skid steering can probably use a higher value as they cannot turn as rapidly as a normal steering rover.

Regards,

TCIII ArduRover2 Developer 

Comment by MikeRover on March 2, 2014 at 3:33pm

@Thomas, without diving ito the code, do you know how the L1 period should relate to the turning circle, or what it corresponds to in "reality"?  From some of the doco it seems to be the distance in front of the vehicle/along the track that the "fake" waypoint sits.  Does that mean less maneuverable vehicles should have a higher period?


Admin
Comment by Thomas J Coyle III on March 2, 2014 at 9:35am

Hi All,

Paul Riseborough's latest version of the Pixhawk EKF code works very well. Course repeatability is excellent and there is reduced overshoot at the end of sweeping turns.

I found only two issues:
With EKF enabled, the rover is not as aggressive in the turns as the DCM.


The Pixhawk LED never went green when everything is a go, yet the rover performed flawlessly in all aspects.

For those of you with Pixhawk equipped rovers, the Pixhawk code with the EKF function can be found here: Pixhawk firmware with EKF Set AHRS_EKF_USE to 1 to enable.

Regards,
TCIII ArduRover2 Developer


Admin
Comment by Thomas J Coyle III on March 2, 2014 at 8:51am

@Antonie,

I have vetted the ArudRover2 firmware skid steering function with a Pixhawk. I have not tried it with an APM, but it should work okay.

How many sats do you see and what is your HDOP before you go into the Auto Mode.

Also, on the Thumper that I was working with, I had to raise the GPS/Compass module about 3" above the top of the Thumper chassis to avoid the motors' electromagnetic affect on the compass when under power. The compass would vary about 40 deg from the true heading when under power. Are you using the APM2.0 internal compass or an external compass?

Regards,

TCIII ArduRover2 Developer

Comment by Antonie Kruger on March 2, 2014 at 7:13am

Hi Thomas, thanks - yeah, I was just there....not before though. I'll work through it. I'm out at the field tomorrow morning. Will continue tuning then.

NAVL1_Period was kept at default. Turning radius down to 1m and I found the throttle slew - thank goodness for this. I'll take up the NAVL1_Period as a first attempt tomorrow.

Would you suggest moving the skid steer control to the APM and disable the mixing on the Wild Thumper controller. I suppose this way the skid steer behaviour can be better understood if mixed in one place.

Thanks again.

Antonie.


Admin
Comment by Thomas J Coyle III on March 2, 2014 at 7:01am

@Antonie,

My parameter settings will only work for a NC that is using the built-in skid steering function.

What value do you have NAVL1_PERIOD set to. Low values like 5 - 6 will cause weaving. Try 7 and up.

Have you read this Wiki section about tuning: Tuning

Regards,

TCIII ArduRover2 Developer

Comment by Antonie Kruger on March 2, 2014 at 6:49am

Hi Thomas, thanks for the prompt reply.

My APM is not in skid steer mode. The speed controller board I'm using is the Wild Thumper controller. The Wild Thumper controller does the mixing.

"Have you calibrated the ESC to the transmitter throttle?" - In Manual mode she runs fine. It is only during coarse corrections in auto mode when the oscillations start - not sure what you mean by this.

This is the reason I'm asking for an APM setup and settings.

Some pics of my rover:....added to the top.

APM2 - on-board gps bypassed - external ublox 6P added.

Thanks

Antonie

 
 
 

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