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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: 401
Latest Activity: 13 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

Contributing to giving sight to AV's

Started by RoboBill. Last reply by RoboBill 13 hours ago. 56 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

APM:Rover Questions

Started by Nakia Brewer. Last reply by Nakia Brewer on Wednesday. 5 Replies

Howdy all,I am currently building an RC/Autonomous Mower and have some questions I could use some help with.Currently I have the mower fabrication complete and as of yesterday I have the mower…Continue

To Start Rover

Started by yuvraj. Last reply by yuvraj on Monday. 8 Replies

How to start make an autonomous rover so what i need about the components please explain me sir so that i can start my work. so please provide me a which type of transmitter an receiver or any other…Continue

using the rover as a auto sentry with audio and video?

Started by mark sahf. Last reply by mark sahf Jan 23. 2 Replies

Has anyone made the rover into a roving security system? I have hacked Roomba and reprogramed with a tether I make then removed parts not needed and added security items and programed it to guard the…Continue

Comment Wall

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Comment by MikeRover on February 16, 2014 at 2:42am

@Bruce, the current ratings are at 25C, and they de-rate from there. From the specs, it looks like the motors shouldn't pull more than 7A, but if your chassis is enclosed, or you're somewhere where the ambient temperature is 30+C, the extra margin may be useful. I'd assume Thomas went for the 25s for a reason, unless he had it lying around.

 

@Antoine, the Sabertooth can do ramping internally, but you need the DEScribe software and DELink USB converter to set it.  I don't know if you can substitute another USB/serial converter.

 

"Ramp Time

This is the time the driver takes to go from full reverse to full forward or vice versa. High ramp rates give a slower-acceleration, softer feel."

Comment by Antonie Kruger on February 16, 2014 at 2:21am

HI Guys, thanks TC3, great job. Would you be porting the skid steer implementation to the APM2 boards? I have a few questions that I need some help with. I have a wild thumper 6wd chassis with the wild thumper controller board. I fitted my apm2 board with telemetry.

Q1. When the controller is instructed to apply 50+% speed to the motors from 0, a lot of stress is placed on the gearboxes in the motors. It is not long before the drive gear in the gearbox strips. Would it be possible to manage the application of power to the motors over a longer period. I'm not sure if I'm explaining this right. The effect I'm after is : When I instruct 100% power forward the controller should not apply 100% immediately. It should accelerate from 0 to 100% over a time period to reduce the torque forces on the gearboxes to lengthen the life of the hardware.

Q2. Does anybody know of better quality motors for this chassis or just gearboxes. The stock boxes sucks. Seems like the gears are mild steel or cast iron. Real cheap crap.

Q3. Can the APM2 rover software take a NMEA string from a serial port for navigation. The reason for asking is that I use a robotic survey instrument to lock onto a 360 prism mounted on the rover. From here I transmit the coordinate to a FEZ Cerb40 netmf board that translates the coordinate into the needed NMEA strings, alternatively using a RTK GNSS receiver mounted on the rover to feed the needed NMEA strings to the controller.

Thanks,

Antonie

Comment by Bruce D. Sidlinger on February 16, 2014 at 1:39am

Beautiful, and I was just tonight ordering that chassis, the high gear ratio (low speed) version. Question, would this controller have been enough, do you think? http://www.dimensionengineering.com/products/sabertooth2x12rc

Comment by Gary McCray on February 15, 2014 at 10:02pm

Really clean install TC3 how do you like Wild Thumper?


Admin
Comment by Thomas J Coyle III on February 11, 2014 at 5:39pm

Hi All,

I would like to announce that I have successfully implemented the Pixhawk firmware skid steering function on a 6WD Wild Thumper chassis using a Sabertooth 2X25 motor controller setup as two independent motor controllers, one for each side of the Thumper chassis.

Here are some pictures of the Thumper and its Pixhawk subchassis:

I raised the GPS/Compass module above the subchassis using a 2.5" high platform to mitigate the effects of the front motors' electromagnetic field. I got the compass deviation under power to go from an offset of ~40 deg to ~2 - 3 deg using the raised platform.

Regards,

TCIII ArduRover2 Developer

Comment by MikeRover on February 6, 2014 at 6:32pm

I've copied my AUTO mode questions to the [url=http://ardupilot.com/forum/viewtopic.php?f=26&t=6024]APM forum[/url]. Keen to hear others' suggestions.

 

 

Comment by Gary McCray on February 5, 2014 at 6:21pm

Hi Tom,

I haven't installed telemetry yet, but might be a good idea to do so soon, sort of taking this one one step at a time.

I have been fully charged though and limiting total running time to less than 8 minutes though with plenty of battery when I get back.

I will eventually replace with serious LiPo, but using stock NiMH for now.

However, you are right it could be power surge causing resulting short term voltage drop, I will look at logs and see what they show, should be obvious there.

Even on uneventful runs.

And of course, unlike APM, PX4 won't reboot in a useful fashion because you can't rearm possibly it might be worth removing (or modifying) this "safety" feature for this particular use.

It is getting better, now normally fails to Hold and haven't had another runaway - - - yet.

Turning down the Cruise speed probably has the bonus that it doesn't accelerate as hard so pulling less current and lowering voltage less - reducing likelihood of brownout.

Definitely do not want to do this in a small yard surrounded by 100'+ pine trees and a 2 story house though - multipath seriously screws it up on auto.

(You can see it wandering all over the place on MP even when it is sitting still.)

Not a problem though I already knew that.

It's getting there.

Thanks again,

Gary


Admin
Comment by Thomas J Coyle III on February 5, 2014 at 2:50pm

@Gary,

I had a case where I didn't keep track of the charge on one the NMHi batteries in one of my Slash Rovers and had a brown-out occur when I punched it hard in the Manual mode and the APM reset and the rover ran until the APM rebooted and went to neutral on the throttle:-)

Now I never let my NMHi 7 cell (8.4v) battery go below 8.5vdc. They will charge up to around 9.8vdc using the peak charging method and fall back to around 9.4vdc when I start to use them. Do you have the battery voltage setup in your telemetry?

Regards,

TCIII ArduRover2 Developer

Comment by Gary McCray on February 5, 2014 at 1:59pm

Hi Thomas, I have now also set my receiver failsafe to throttle mid position.

And as I said below tuned down the Cruise Speed and Throttle.

I don't think it should be a brown out causing the PX4 to reset.

I have my fully charged 8.4 volt NIMH battery wired directly to the PX4's built in power module and that seems like it should be plenty of battery and I ran the ESC BEC and servo power leads straight together as you suggested so ESC power isn't even going to the PX4.

The PX4 power supply comes straight from the cars battery.

Still, possibly with a real power surge or high current draw by motor I suppose it is possible it is pulling it down too far. (Have to think about that for a bit).

I have now configured pretty much everything I could find to encourage it to end up at 1500 pwm if anything goes wrong, we will see.

Thanks for your input it has been very helpful in finding my way through the intricacies of setting one of these up - I'll get there. :-)

Best Regards,

Gary


Admin
Comment by Thomas J Coyle III on February 5, 2014 at 12:48pm

@Gary,

Close, but no cigar:-) Sorry to hear about the runaway. Never a pleasant occurrence!

I always start out with a CRUISE_SPEED of 2 - 3m/s with a new rover.

You might want to set the CRUISE_THROTTLE at 25 - 30.

All of the Traxxas ESCs that I am using will turnoff with their on/off pushbutton no matter what happens to them. No exceptions.

Sounds like there might have been a brownout as the PX4 went into reset.

Unlike the APM, the PX needs to be armed after boot-up. I had Tridge set the throttle output of the APM to 1500us (neutral) after boot-up so if there was a reset, the rover would stop as soon as boot-up was complete. Not perfect, but something is better than nothing:-)

To be honest, I have never run my PX4 equipped Traxxas 1/16 Fiesta rover in Auto, but never had any issues in Manual.

Also, never had a runaway with my Pixhawk equipped Traxxas Slash Rover in Auto --- yet:-) 

Regards,

TCIII ArduRover2 Developer

 
 
 

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