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Power Pig - My 6WD/6WS Clod Buster based truck

Discussion in 'Road Giants 6x6/8x8/10x10' started by potatocat, Dec 31, 2015.

  1. potatocat

    potatocat Well-Known Member

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    There's no doubt about it... the Power Pig has a face only its parents could love. Of course I am under no illusions about the rudimentary construction and design of this truck compared to my other ones- but I started building this when I was 13 and it still runs today!

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    Some general specifications about the truck:
    Overall length: 34"
    Wheelbase (F/M, M/R): 15", 8"
    Electronics: Triple SkyRC Leopard2 60A ESCs slaved to a single channel
    Steering: Triple servo (2x Futaba S2004, 1x Hitec HS422 Standard) slaved to single channel
    Weight: 16 lbs

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    The chassis was fabricated for me as a favor by a local window and door making company (Gamco Corp). It is sheet aluminum made on a bending brake to be 3" wide. It is full of holes as you can see from past mistakes and experiments. Although at first I was ashamed of all these errors I now wear them with pride. Not too many people my age can say they still have a running R/C model from when they were a teenager.
    Pictured above is an older configuration when I was using a single stick pack instead of the triplet setup now...


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    The axle mountings are simple galvanized steel angle brackets. They don't totally line up but they are close enough. The only power tool I had at the time was a cordless drill which I mounted into an old rowing exercise machine which worked as an improvised 'sideways' drill press. I don't have any pictures of that crazy contraption but I wished I had taken some at the time.

    The only internal modifications are ball bearings in the gearboxes and at the steering knuckles. The motors until recently were silver can 540s. I upgraded them to a triple set of SkyRC Toro 10T brushless motors after experiencing brush failures on two of my silver cans. Otherwise I am keeping much to the spirit of a 'super stock' 6x6.

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    For a long time the truck did not run with a body. The Tamiya Bullhead was a relatively new addition- along with the name of Power Pig. I had stickers made from several different vendors to experiment with - the ones mounted on the body right now came out best but were a bit underwhelming at the time. The coloration on the vinyl seemed pretty unsaturated and dull compared to the silkscreened vinyl factory sheets from large production run vendors. Still, they are unique to me and I am happy with them overall.

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    The truck for a long time also ran the silver cans off one battery pack. I also recently modified this arrangement to match the weight balance of my other trucks. The batteries sit inside the chassis between the middle and rear axles. Accessing them is a simple pin and body clip mechanism. I kept the aluminum unfinished and raw in the spirit of the rest of the truck.

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    The turning radius is very 'soggy' and can be somewhat inconsistent at times, but I can get about 5 feet out of it normally with 6WS. This is using standard strength (not high torque) servos, along with the stock Clod center-mounted servo saver which explains the 'sogginess' and inconsistent turning behavior. The picture below shows the size of the Pig in relation to my other 6x6 trucks. Certain design elements are common across all three rides as well. Using the Clod axles gives it the big footprint of a 'cartoon scale' rig but it is super lightweight compared to the other two trucks. Theoretically I could just improve the steering servos and trade out the motors/ESC for something with a lot more oomph but I really do want to keep the spirit of the machine similar to how it was originally intended.

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    The truck actually handles very nicely- it drives like a stock Clod but is much more resistant to rollover. Even with the crappy spring shocks the truck is surprisingly consistent on the bumpy stuff. I chalk that up to the long wheelbase and a slight toe-in on all three axles though. I have not radar measured this truck yet, but in stock silver can form I got about 10mph out of it. With 14.4v it got 15mph with somewhat inconsistent sprints. The current setup is 7.2V NiCd packs (which I still have a lot of) and if I had to guess, it is probably somewhere around 13mph with the brushless motors.

    No major additional work is planned on this truck, but it will serve as a testbed for some avionics/telemetry gear and software I am developing. I keep it ready to drive on a moment's notice just in case. I don't get to bash nearly as much and probably won't until my daughter gets a bit older but that's okay. I have a feeling she will be with me driving out there in the not too distant future.

    Well, that's where it is so far.
    Thanks for reading!
     
  2. potatocat

    potatocat Well-Known Member

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    Hi all,
    I made these updates some time ago but I started working on this truck recently.

    Oh boy, here I go killing again! It's time to get the onboard telemetry and avionics project running.

    First I installed reed switches on each wheel. This is to measure wheel RPM.
    If I had to do this over again, I would have used rotary encoders since they would give me much higher resolution... because with reed switches I can only sample at 1Hz or 2Hz. Its not enough response time to do fancy things like ABS or traction control. But oh well. This is a start.
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    The cavity of the switch is filled up with clear silicone caulk.
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    Wheel hubs have neodymium magnets caulked into them using the same method.
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    I found a neat little plastic enclosure in my pile of hoarded garbage to use for the electronics case.
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    Not a very elegant mounting but it fits.
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    Here is the compute box with some of the hardware mounted in. A Raspberry Pi 3B is installed here, along with a DC buck stepdown power supply.
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    A pair of Arduinos doing the actual sensor collection live above the Raspberry Pi.
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    Analog thermistors are wired up to measure temperature. The ESCs, batteries, and motors each get one of these things. All of the wires then run back up to the electronics box.
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    Now things are getting wired up and plugged in. Here is where I left the project, and now it's software development time...
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  3. Antho11

    Antho11 Studio Forums Elite
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    That's a really cool idea using the Arduinos and Raspberry Pi. Are you going to monitor the telemetry in real time?
     
  4. potatocat

    potatocat Well-Known Member

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    Thanks! The telemetry is going to be a combination of realtime and archived data. A smartphone on the transmitter side will see a webpage with live data. All of that data is saved to the onboard MicroSD card where it can be synced up with a script to render processed video. The result will hopefully look like something out of Gran Turismo, with an overlaid HUD-style dashboard while the video plays.
     
    Bluedually and Antho11 like this.

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