Admin

TCIII ArduRover (Traxxas E-Maxxs) Build Log

Hi All,

Finally getting my ArduRover moving (pun intended) again now that I have retired and finally resettled to Flordia. I have included a couple of pictures. One is the basic Traxxas E-Maxxs Chassis with a 1/4" thick HDPE plate attached between the body support posts. The other pictures are a mockup of the obstacle avoidance sensors and Arduino Uno processor. There will be another plate mounted 2 and 1/2" above the lower plate and will support an APM1/Oilpan, GPS, compass, 3DR 900MHz telemetry module, a GoPro HD camera (just like JLN), and assorted batteries and running lights. I plan to test the obstacle avoidance and navigation functions separately and then integrate them once they function on their own.

Regards,

TCIII

 

Basic Chassis with Platform Side View.JPG

Chassis with Sensors and Arduino Uno Side View 2.JPG

Chassis with Sensors and Arduino Uno Front View.JPG

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  • Fantastic build log Thomas, just found it today as research into a faster rover which I think will be baeed on an EMAXX.

    Great job!
  • Admin

    Hi All,

    I have completed my Traxxas E-Maxx rover, which I am calling "Crusher", except for tidying up the cabling. I always wait until I am sure that I am not going to have to move anything before I finalize the cable tie down.

    3689579968?profile=original This is the front view of the Crusher. The PM can be seen in the rear. The 3S LiPo that powers the PM is on the opposite side of the body mount tower. The navigation board is in the front just behind the GPS/Compass module. The Spektrum BR6000 receiver is on the left and the 3DR telemetry radio is on the right. The APM2.6 is mounted on helicopter gyro gel.

    3692860920?profile=original

    This picture will give you an idea of how big the 1/8 scale E-Maxx Crusher is in relation to a 1/16 scale rally chassis. The rally chassis houses a PX4 believe it or not!

    3689580019?profile=original

    This picture is a side view of the Crusher with a 1" per unit tape measure in the foreground to provide some scale to the size of this E-Maxx chassis.

     

    Regards,

    TCIII ArduRover2 Developer

     

    https://storage.ning.com/topology/rest/1.0/file/get/3692860920?profile=original
  • Admin

    Hi All,

    Here are the latest pictures of my Traxxas E-Maxx 1/8 scale 4WD rover. I have substantially changed the configuration from earlier this year by removing the top superstructure and mounting the navigation components on a plate between the front body mount towers. Since these two photos were shot I have added a Spektrum BR6000 Receiver on the left side of the APM and a 3DR 915MHz telemetry radio on the right side. Also I have mounted a 3DR PM on the front side of the rear body mount towers and a 3S 2200mahr LiPo on the back side to power the APM and a 900MHz video transmitter.

    Regards,

    TCIII ArduRover2 Developer

    3692853448?profile=original

    Front View

    3692853696?profile=original

    Top View

  • Admin

    Hi All,

    Finally did my Federal Tax Return and found out that I will have a little extra money in my pocket within the next couple of weeks. So I decided to buy a Traxxas Slash roller chassis to use in the Sparkfun AVC next year.

    Why the move to the Slash from the E-Maxx? Well, testing has shown that the E-Maxx has too high of a CoG for good cornering on dry pavement. The E-Maxx works well in the off road environment while the Slash, even though it can run in the dirt, is great for dry pavement. I plan to save the E-Maxx for off road RoboMagellan competion and will move ahead with the Slash for the Sparkfun AVC.

    I did a lot of research on the Slash and found that there are conversion kits to use the Traxxas Rustler chassis to lower the CoG of the Slash. However the cheaper ones compromise the chassis structural integrity and the more expensive ones might as well not be considered to be a Slash. So I have found that there are sway bar kits of reasonable prices for both the front and rear of the chassis. Also the front bumper can be removed and replaced with a non-flexing aluminum version, but I will have to add padding to the front to prevent damage in the event of a crash. The non-flexing aluminum bumper will make the front sway bar more effective than the original flexible version.

    I plan to keep the stock brushed motor and controller for now as they are pretty potent with the correct gearing. I think that straight away speeds of 30mph and fast cornering speeds with the latest version of the ArduRover2 code that allows for the cornering speed to be a variable parameter along with the ability to set the distance from the turn when the speed reduction begins to take affect will make the Slash a potent competitor.

    More later.

    Regards,

    TCIII

  • Admin

    Hi All,

    Today I decided to test the ArduRover2 learning function. I am presently using a Spektrum DX7 R/C transmitter that has a 2-way Gear switch and a 3-way Flap switch. I use the Flap switch to set the ArduRover mode and the Gear switch to designate a waypoint when in the learning mode. The Gear switch must cause a low to high to low transition for a waypoint to be logged in the APM memory. That means going from a PWM value of ~1100 to ~1800 and back to ~1100.

    I ran my rover on my local short course out in front of my town home. Using the Gear switch I recorded seven waypoints as I drove the rover around a long, narrow rectangle. At the end of the course I was going to bring the rover in to see if it had recoreded any waypoints as ArdurRover2 v2.20b did not record any waypoints when in the learning mode. However I decided to put the APM in the auto mode to see what would happen. The rover hesitated a moment and then took off on the course I had recorded previously in the learning mode. The rover completed the course and returned virtually to where it had started. Nothing like the sweet smell of success!!

    Now, if Tridge can get the IR sensor obstacle avoidance working we will have a baseline from which to begin to add enhancements.

    Regards,

    TCIII

  • what did u use to hold the ultrasonic sensors ? im curious to know.

  • Admin

    @Vijay,

    Yes, I did get the MINDS-i Uno obstacle avoidance system working very nicely by itself. I had to fine tune the code to work with my 6WD rover, but when I got it working it was very effective at obstacle avoidance. Due to having three PING sensors up front, it was particularly good at avoiding very wide obstacles such as walls. When it would approach a wall, it would start to turn to the left at which time the right sensor would still see the wall so the rover would continue to turn left and move parallel to wall until the right sensor would no longer detect the wall at which time the rover would make a right turn and continue forward. The MINDS-i will be integrated between the APM throttle/steering output and the the rover ESC/servos. As long as there is no obstacle detection in progress, the navigation output of the APM will control the rover ESC/servos. As soon as an obstacle is detected, the obstacle avoidance system will ignore the APM navigation input and take appropriate action to avoid the obstacle. After that, the obstacle avoidance system will hand control back to the APM navigation input which will make any course corrections necessary to continue on to the next waypoint.

    Regards,

    TCIII

  • This is a great build log!  I am looking to build a 4wd rover-esque project and this gave me a lot of insight.  I am using a Wheely King as my chassis of choice.  I will be using a brushless electric motor system and a steering servo.  Power will be from a 5000mA 2s lipo battery.  I am kind of a noob to programming arduino so will be learning a lot on the way but my background is in engineering.

    Had a few questions in regards some items to purchase that I was hoping I could get some help on:

    1.  What type of APM is recommended?  Should I get APM1 or APM2?  Also, what is "Uno" compared to the other other Arduino processors available?

    2.  I have a a 3-channel radio that I will be using for manual control.  However, I want to have the ability for 3 axis movement on my camera as well.  Will probably need to get a 9-channel radio instead once I get that component integrated.

    3.  Any recommendations on micro cameras?  Dont want to spend a lot for one but want something that is pretty decent.

    4.  Any recommendations on wireless transceivers and antennas?  I would like my camera video to be wirelessly sent to my laptop for viewing (or at some point I will write an Android application to view the video). It looks like 910 Mhz is the recommended frequency for video.  My radio is 2.4Ghz.  I wil also probably want telemetry sent to my ground station.

    That is all for now.  Still doing a lot of reading on the diydrones to get up to speed on integration.  Look forward to posting pictures once I have a decent setup.  Thanks!

    Chirag

  • Admin

    Hi All,

    I would like to take this opportunity today to announce that I finally got my 6WD rover to follow a three waypoint course. Setting up the Home waypoint and then the subsequent waypoint was a real learning experience. At first my rover, after loading the waypoints, would move slightly and then stop. At first I was mystified until I looked at the MP waypoint example provided by Linus ( a tip of the hat to Linus here) and determined that my waypoint radius and loiter radius were way too big for a rover. So I reduced the two radii to 5m and 4m respectively. I also set the Default Altitude to 0 and unchecked the Hold Default Altitude. Another thing to remember is that you can move the Home waypoint to anywhere you want. So I started my rover at the front of my drive way and had it head north for about 30m and then head east for about 5m and then head south back to the starting waypoint.

    The rover started out north and proceeded to hit every waypoint that had been programmed. Based on what I have seen, I recommend experimenting with reducing the waypoint radius towards 1m if you are using the new LEA-6 GPS like I am. Also I am using the latest HMC5883L compass which seems to be more stable than the HMC5843-TR that I had been using. As far as the IR avoidance sensor, it worked pretty well except that the course deviation period to the right was much too short to avoid a wide object and should be made an MP variable like the detection range is. I do not feel that the sensor produced too many false returns, as observed by Chris Anderson at Sparkfun, as it worked well in 4in tall grass.

    Another interesting observation was that moving the control switch from auto to manual and then back to auto would restart the course without having to reset the APM. Also, I found that I could start the rover facing backwards and 5m from the Home waypoint and it would turn itself around and head directly to the Home waypoint and the proceed to the next waypoint. Neat!!

    Otherwise I feel that I am off to a great start and just need to learn more about the characteristics of the system and how to improve waypoint accuracy.

    Regards,

    TCIII

  • Admin

    Hi All,

    A long time ago I built an ArduStation, but never utilized it until now. I updated the software to the latest version by Heino Pull that works with Mavlink 1.0/0.9. I have two 900MHz Xbees that I am using for the RF link. The rover Xbee is mounted on an Adafruit 5v/3.3v converter board that has a Tx/Rx interface just like the 3DR 900MHz telemetry modules. After turning on the ArduStation, I then started the APM1/Oilpan on the rover and then started the feed on the ArduStation. I got the heartbeat indication and then switched to the Flight Data screen. The Flight Data screen displayed my sat lock and the number of sats plus all of the other flight parameters such as roll and pitch. Sweet! Now I do not have to have my laptop operating with MP to get rover status when I am out in the field. The next step will be to add the 3DR OSD to my Readymaderc video transmitter and GoPro camera setup on the rover.

    Regards,

    TCIII

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