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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.

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Latest Activity: yesterday

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

Apm Rover in tractor setup.

Started by Matthew Reimer. Last reply by Grant Morphett yesterday. 102 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

New Localization Kickstarter promising 10 cm accuracy

Started by RoboBill. Last reply by uavfans on Friday. 6 Replies

Howdy All,I stumbled across this project yesterday. It uses UWB Decawave chips. The Pozyx is a Arduino shield. The system is made up of 4 anchors around…Continue

APM 2.6 UGV - 2 motors + chain system + ArduRover/APM control

Started by U Hobbies. Last reply by U Hobbies on Wednesday. 2 Replies

Okay, so we're planning our new project, basically a rover driven by 2 motors and a chain/gear system, almost exactly like this: …Continue

Tags: control, APM, motors, 2, 4WD

Follow Me Mode?

Started by Brianman. Last reply by Grant Morphett on Monday. 5 Replies

Was Follow Me Mode ever implemented into APM Rover?Continue

Comment Wall

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Comment by Antonie Kruger on March 12, 2014 at 8:21am

@RoboBill&&Thomas,

At risk of sounding brutal, I do not think this can be called a poor man's RTK. The receivers we use are L1 only. For a RTK solution you would require a L1&L2 +++ receiver with a fixed(normally) base transmitting a correction.

Regarding the 2 GPS's. I would not use the 2 GPS's to derive a baseline length or distance. We've tested RTK systems(<0.02m 2D accuracy) on drilling rigs for guidance. Looking at the 20mm accuracy - of one is 20mm left and the other 20mm right you have a 40mm displacement over a short base - in simple terms. Now imagine using L1 only with a 2m accuracy.

If only ublox would release that L1&L2 receiver they're hiding in the R&D department.

Antonie

Comment by RoboBill on March 12, 2014 at 7:48am

Regarding having two GPS' on a rover....Thank You! 

1) Will this be sort of a poor man's RTK?

2) Do you think you can reach to less than 12 inch relative accuracy?

3) I assume there will be a distance between GPS' parameter. Please consider the possibility of mounting the GPS' both in line with rover and also on the sides. In my case that distance will be close to 3 feet. 

3) If you'd like, I'd be happy to help test your code.


Admin
Comment by Thomas J Coyle III on March 11, 2014 at 3:00pm

Hi All,

I would like to announce that Tridge and I are presently testing the use of two GPSs on a Pixhawk equipped rover. We are in the process of collecting data from both GPSs to assess the effectiveness of using two GPSs and to prepare for generating code that can take advantage of using two GPSs.

Regards,

TCIII ArduRover2 Developer

Comment by Gary McCray on March 5, 2014 at 11:28am

Hi Mark,

PX4Flow has a built in Sonar which is used to accurately provide height information and PX4Flow is intended to only be used within range of sonar (for optical flow use in any case.)

You are right it probably could be used looking down on a rover, but it's proximity to the ground would make effective resolution very high and some surfaces would probably work a lot better than others, rug, carpet, asphalt or concrete for instance.

The PX4FLOW is really rather more than a mouse detector, it is a fairly high resolution near IR sensitive camera with binning capability attached to a quite powerful microcontroller of it's own.

This means it could be used for other more complex tasks as well.

Comment by Mark Halliwell on March 4, 2014 at 11:40pm

@Gary,

Downward looking Optical Flow could be an interesting addition to the Rover code as it would give us the opportunity to try optical flow odometry for hi-res localization. As a glorified optical mouse (field mouse?) it could offer supplementary information to be read along with GPS data. As I understand it, the major challenge of optical flow to the flying community is the measurement of height to include in the calculations. On a rover, unless it's doing wheelies or similar, the height would be more or less fixed and known. That said, ground surface might be an issue with long grass affecting  the height.

As I understand it, the current PX4FLOW would need a different lens to get the focal length down to a level better suited to a rover.

Mark

Comment by Gary McCray on March 4, 2014 at 10:05pm

@Thiago, At this time I do not believe Optical Flow of either type is enabled for Rover and only Copter has optical flow enabled and only for simple Optical Flow system not for PX4FLOW.

In fact Optical Flow as it is enabled for Copter is not really applicable to Rover.

It is down looking and establishes a horizontal displacement / correction only.

Ostensibly, optical flow from a rover might be forward looking and that is a whole different kettle of fish.

For this use, PX4Flow would probably be mandatory and more likely 2 of them and a lot of custom programming of the PX4Flow itself. They are also serial, daisy chainable and have considerable on board processing power so 2 could be used in a binned stereo vision application to good effect on a rover, requiring only a seriously large firmware development.  

Best Regards,

Gary 


Admin
Comment by Thomas J Coyle III on March 3, 2014 at 5:24am

@Thiago,

Here is a link to the APM: Rover Wiki: Rover

You might want to post your questions concerning using the optical flow sensor in the Sensor & IMU Discussion Forum: Sensors GPS support can be found here: GPS

Regards,

TCIII

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

 
 
 

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