Hi,
Let us present AirbotServices' style Ardurovergasmistic week-end gaming - lvl 1. It is mandatory to pump the volume up when watching this video.
This all-terrain monster consists in a Pixhawk controller running latest Ardurover code installed in a 6 AWD chassis.
All six wheels are self-powered with an independent motor and are using a 75:1 gears ratio. Such a high ratio gives it a tremendous amount of power, as you may have observed in the video. Certainly not made for high speed rover sissies :)
In terms of equipment, in this first stage, AirbotServices ' rover remains practically naked, still equipped with:
-a M8N GPS+compass module
-3DR telemetry radio
-3DR power module to keep an eye on current and voltage in real time
-A Sabertooth dual motor driver (credits to our community Ardurover expert, Thomas, for helping me out on the settings !)
-FrSky D4R receiver
-Payload capacity (not counting chassis): 6kg
In a second stage, camera(s) setup with stabilized gimbal and vibration dampening. This will be quite an interesting challenge to get vibration free video on a rover and a level2 video might follow...
Ultimately such a little beast will be given a brain via a companion computer for "ground/underground" agricultural purposes. We were thinking on adding a small quadcopter companion, taking off/landing on top of it, using precision IR beacons of course, that would relay images to the rover companion computer. Or even swarms of micro quads launched by the rover ?
What do you think ?
Comments
@Antonie,
I built a 6WD rover chassis using geared motors from Lynxmotion that were made in Taiwan. Fortunately the motors came with spare metal reduction gear sets as the original plastic reduction gears in the motors quickly stripped.
I do not like using the motor shaft sleeve bearing as a wheel support as they will quickly wear unless they are lubricated consistently.
I would like to see someone come out with a 6WD rover where two large brushless motors each drive three of the six wheels through driveshaft/differential power trains and the wheel half shafts are supported by sealed bearings. I have seen custom made versions of this kind of rover power train, but a commercial version would be very expensive, but probably very bullet proof:-)
Regards,
Tom C AVD
HI Hugues, great video. Love the Thumper. Just a note on the slew rate of those motors. The gearboxes fails quite fast if you do not spread the load transfer over half a second or so....or dump the stock motors and get a better quality one. I cut the spikes off my tires to try and reduce the torque on the axles. I also replaced the transistors on the H-bridge after they fried when the Thumper fell in a ditch during an auto mission and the undercarriage got stuck. I'm using the Wild Thumper controller - it is suppose to have a current monitoring system that blows a fuse when thing goes south, but it didnt. Replaced 2 motors as well. In total 5 motors now. 3
with
stripped boxes and 2 fried.
Great idea, great chassis but those motors and boxes are not. I'm still looking for better quality ones. I'm considering a scaled up build with bigger motors for better reliability.
I forgot to mention that my Thumper works for a living. It is not a hobby rover. I use it to collect quality control samples on construction works being tracked by a survey instrument:).
Thank you all for comments.
@Healthyfatboy, this is my first "real" rover experiment. I had played a year ago with a small plastic chassis (actually the one shown in the ardurover wiki) from hobbyking. Parts were literally falling apart and this chassis was unable to drive on anything else than a flat road. In the end it came to be expensive because of all the replacement parts I had to buy and the time I fiddled on it. Thomas advised me too on trying "Traxxas" brand chassis (e-maxx for ex). I have never tried it. I choose for the Dagu chassis in place of the Traxxas because of the future use I intend to do for agriculture where I need an all-terrain vehicle that drives slowly enough. The e-Maxx is more of a speed vehicle (the smallest version drives at 30 mph!) for racing, not for agriculture.
@Felix, Yes that is what I will try next too. FPV blast !
@Cala, come one, let you be tempted by this orgasmic robotic blast ! I did not test the radio range on the rover. This can be a nice test I can do. I will report back. However in the intended field use, autonomous behaviour will be used , so no RC control intended (so we don't care of the radio range really in this application).
@Gary, your stampede experience is useful for me as it confirms what i suspected too. The low gear ratio of these Traxxas vehicules make them drive way too fast for agricultural usage. And , as you say, I do not want to start a "pimp my rover" thing where you need to customize complex differentials, clutches, gears and the like... I also notice in Europe the price of Traxxas chassis is very high, almost triple the price of this Dagu chassis (motors included).
I would say the weak points of this Dagu chassis are the brushed motors (i would prefer brushless motors) and some weak wheel attachment design. This could probably be customized to improve it. What's good though is that replacement motors+integrated metal gears are sold quite cheap (about 12 dollars/motor).
Hi Hugues,
Excellent video.
Great to see the Dagu Wild Thumper chassis actual performance capabilities.
https://www.pololu.com/product/1561
I was a bit concerned about reports I had heard relating to motor and transmission reliability and longevity, but it certainly seems to perform really well.
I have a Brushless Traxxas Stampede with a PX4 and It is a blast.
But it is geared higher than I would prefer and they don't have sufficient gears available to gear it as low as I would like.
I didn't like the Summit because it uses a brushed motor and I also thought the shiftable transmission and differentials added needless complexity.
The 6 wheel/motor approach to the Thumper seems very robust (and simple).
And judging from your video the motor wheel articulated suspension seems very effective.
Best regards,
Gary
:o :o :o time to time I think's about rover utilities for farm but I never open nothing to see them, I have a lot yet with my flying vehicles and have the erroneous concept that aren't for difficult terrains like row crops, please Hugues don't share this temptations LOL;
My doubt is with radio and video signal with rovers, you can go far from you? I suppose that you have to put higher your antennas? how far you can go?
yes, it is a really nice chassis, I have the same - as well with a Pixhawk on top. But I didn't have time to set it up for autonomous driving, so far I drove it FPV with video googles (which is a lot of fun).
Definitely impressive.
Have you compared it to something like the Traxxis Summit? The Dagu has some advantages like lower CoG, zero turn radius, and good climbing ability due to the CoG and 6 wheels with less chance of high centering. The Summit is quite capable from some testing I have done in the past but I'm curious what the pros/cons of each platform would be.
The chassis - isn't it Wild Thumper 6WD from HK somehow modified?
Terrain ability is awesome ;-)
Dagu
Cool. Who make the chassis?
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