[PROJECT] Heavy Duty R/C Tool Box

Discussion in 'Other Toys/Hobbies' started by ShadowBurger, Jan 18, 2017.

  1. ShadowBurger

    ShadowBurger Member

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    UPDATE2: it really drives!



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    UPDATE: It drives!



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    So this one should be an interesting build :weirdo:

    What is it? Why?

    Basically, I go out to fly quadcopters and need to take with me:

    • spare parts
    • battery charger
    • camping chair
    • lead-acid battery to run charger - more is better
    • tools
    • marquee, for sunny days
    • water / food
    • other stuff?

    ...not to mention the quadcopter(s), its transmitter, batteries and other bits. Sometimes the places I fly are a bit of a walk from the car and carting all that gear suuuuuuuucks :tired: I thought about getting a wheeled toolbox, but the wheels were all way too small for grass, gravel, a bit of mud etc., and the sizes available weren't really going to solve my issue anyway. Anything suitable was going to cost an arm and a leg.

    So I queued the music... and came up with:

    [​IMG]

    Rofl.

    I spent a stack of time working out different concepts for its design:

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    what even is this i literally can't even
    [​IMG]

    In essence the design has / must have:

    • dual 100W 24V motors so it can push heavy loads up-hill
    • chain drive to solid rear axle
    • home-made steering servo (combine R/C servo and wiper motor)
    • 980mm length, 380mm width, 380 or 350mm height inc. wheels
    • Must fit in the boot of my Corolla without folding down the seats or removing the parcel tray
    • 8x 12v 5.0Ah lead acid batteries, for charging in the field (easily removeable so I can lift the bastard in and out of the car)
    • Powered by 16,000mah of 6S LiPo
    • SHS steel frame with aluminium checker-plate panels
    • 'roof racks' so I can strap the chair and other big stuff to the top of it with ockey-straps
    • "offroady" wheels so it can get through somewhat rough terrain
    • robust. last thing I want to do is have to carry this bastard anywhere

    It's a challenging design and immediately the decision to make it fit in the boot of my car made me struggle with it. It won't have a whole abundance of space internally due to the mechanics, but it's long - almost a metre - and being able to carry things on top makes up for it significantly.

    The decision to use these two small motors was a strange one but I had two reasons: 1, I already had them 2, they fit within the profile of the wheels themselves and 3, i could have gone with a worm-drive type motor for more torque / cheaper / easier but I wanted this to be quick and, more importantly, able to free-wheel so i can push it without power if need be - these motors have very little resistance when coasting.

    So far I'm using these main parts:

    Integrated Bot Controller to power the drive motors and the steering servo (Made by a local Melbourne engineer! Good kit.)

    100w 24V DC motor x2, from Motion Dynamics - with #25 chain sprocket

    12v worm drive "wiper motor" from Motion Dynamics (i'll run this on a limited PWM duty cycle so it doesn't burn out at 24v)

    hand trolley wheels / axle from bunnings. I bought a whole trolley to get the axle, bearings, and two wheels, then an extra four wheels which also come with bearings for $10 each all from bunnings.

    Other bits will be picked up as needed. So far I have square 12.5mm steel tube and some big bits of 4mm steel 90deg angle which I've found handy and had lying around. I'll be using rivets to attach the aluminium checker plate to the frame.
     
    Last edited: Apr 19, 2017
  2. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    So I figured I'd start the build by building the rear section with the axle, motors and everything, then the front section with the steering, then build the frame around those two parts.

    I begun last night with the drive motors. It ended up being much simpler than I expected to put it together, due to the design of the hubs/bearings that come with the bunnings wheels.

    [​IMG]

    I bought six wheels in total, including the two that came with the whole trolley, so that I can use the extra pair of bearings to support the rear axle and avoid having to make a fixed hub for the rear wheels.

    Obviously I don't want the rear wheels to spin on the axle, so I drilled a hole through the hub and axle and rammed a nail in. I cut the nail off and banged the end flat so it can't fall out. Great! But now I can't remove the wheel from the axle... so I'll have to find a big R-clip to replace it with.

    [​IMG]

    I cut a notch into the angle steel to accommodate the extra hub which I'm using as an axle bearing. It works great!

    [​IMG]

    [​IMG]

    I got a suitable #25 sprocket from an e-scooter wheel on eBay. The hub is huge as its designed to bolt to the wheel, but I wanted to weld it and centre it on the axle, so I decided to weld a washer to suit the axle into the centre.

    [​IMG]

    The washer was a bit big, by a mm or so, so I had to get creative to make it fit. I put it on the axle and let it spin while I held the grinder against it. :Paranoid: :weirdo:

    [​IMG]

    For the right-hand side, I wanted to mount the motors in and hold the hub bearing with a single bit of steel to keep the design simple. I managed to do it with a piece of angle steel the same as the left side.

    [​IMG]

    The motors fit in a perfect position to line up with the sprocket, which is important for chain drive.

    [​IMG]

    A test fit gave a good result :)

    [​IMG]

    I need to elongate the holes for one of the motors so I can tension the chain properly, then attach the left side to the right, then I can begin on the steering setup.
     
  3. mad_mic3

    mad_mic3 Member

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    sweet little project:thumbup:
     
  4. 0M39A_1337

    0M39A_1337 Member

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    Off to a great start.

    Might I suggest lifepo4 instead of lipo? They are far more resilient to high/low states of charge than lipo. A project like this I imagine would benefit from charging up then not worrying about for the next few uses.
     
  5. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    cheers!

    Gonna stick with 6S lipos as I already have them, and they should be overkill for this project really. I've heard a few things about lipos discharging but I put them at storage voltage when not in use anyway
     
  6. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    quick update

    I welded the sprocket to the hub

    [​IMG]

    Quick test fit to check for squareness

    [​IMG]

    Next up I cut some square tube to weld in place between the left and right sides. Cut a new piece of chain to length and elongated the motor bolt holes so I can adjust the tension. Each motor needs its own adjustment as the distance on both sides needs to be a multiple of the gaps in the links, if that makes sense, it's weird working with chain...

    [​IMG]

    Checked the clearance between the wheels and the motor sprockets, bolts etc... it's all very very close. I'm lucky though as so far it's all gone together perfectly.

    [​IMG]

    [​IMG]

    The rear drive section is complete! (chain isn't tensioned there... need to get some more grinding bits for the dremel to elongate the holes)

    [​IMG]

    Next up, I'm onto the steering section. Still waiting on postage for the motor for that, so I might paint the steel for the rear axles in the meantime. I'm not going to use any more galvanised steel as it's shit to weld, shit to paint, and releases toxic heavy metal fumes when burned which make you sick and stay in your body forever :thumbdn:

    EDIT:

    Added some new parts to the list:

    Heavy duty drawer slides

    Continuous hinge - 915mm

    2x spotlights :)

    USB / lighter sockets / voltmeter

    12v-24v DC-DC adapter

    EDIT:

    Got some aluminium checker plate delivered! There's two sheets there, should be enough for a toolbox, and then-some.

    [​IMG]
     
    Last edited: Jan 20, 2017
  7. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    With the 'driving' half done, I spent the morning putting together my steering mechanism. This is the motor I'm going to use to turn the wheels. Once again from Motion Dynamics

    [​IMG]

    I went with some square tube slightly drilled out to hold the king-pins for the steering

    [​IMG]

    I did want to use some solid bar but it was going to take about a week just to drill all the way through one of them, so I scrapped that idea.

    [​IMG]

    I bent some flat bar into a sort of U shape to hold the kingpins

    [​IMG]

    The kinpins and hollow section fitted in well

    [​IMG]

    I welded on some stub axles to carry the front wheels

    [​IMG]

    The whole lot got put together to form the stub axles and carriers

    [​IMG]

    I joined together two cut-down pieces of square tube to form a pitman arm. I had to build it this way because the output shaft on the wiper motor doesn't protude past where the bolts are

    [​IMG]

    It fit nicely and you can see it just clears the bolts.

    [​IMG]

    I took apart my R/C servo and got rid of the gears and electronics.

    [​IMG]

    [​IMG]

    I assembled it back together and mounted it to a piece of steel along with the wiper motor, using a linkage from an R/C car for it to pickup the position

    [​IMG]

    I added some linkages to the stub axles and connected it all together mechanically

    [​IMG]

    There isn't a lot of angle available so the turning circle will be fairly large, but that works in my favour as it'll mean I need less room between the wheels.

    [​IMG]

    Using an arduino to control the wiper motor isn't working great, using the pot as a means of position sensing. I just don't know enough code to make it work, I think it needs some kind of PID controller - it works but it overshoots the position in a big way.

    At the moment I've grabbed the electronics from the servo and found a schematic. I'm going to have a crack at using the circuit to control the motor instead. It uses a BAL6686 H-bridge, which has two logic pins - one for forward, one for reverse, so it should be easy enough to interface the arduino with it.

    [​IMG]

    [​IMG]

    [​IMG]

    Stay tuned for more!
     
  8. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Seems to work :)

     
  9. MR CHILLED

    MR CHILLED D'oh!

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    Looks like a full on build constrruction....good luck. I'll be watching on with interest to see the end result :thumbup:
     
  10. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Just thought I'd share my code for the arduino I used to control my DIY servo. I couldn't find much information anywhere else on the web and ended up having to do this from scratch.

    https://github.com/psYbR/arduino-servo

    I had a go at building a full PID loop, which worked, but ended up sticking with just proportional control as it seemed to work best and I didn't have hours to sit and tune it.
     
  11. psychobunny

    psychobunny Member

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  12. isaakk

    isaakk Member

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    Awesome project! Definitely going to follow along.

    Just a thought, if you make it big enough, could mount a seat on top and ride it out to flying locations? :lol:
     
  13. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Cheers! couple of good reasons: won't fit in the boot of my car, don't want to mess around with petrol, will take just as much work to make it R/C, still need to factor in the cost ($600) on top of the toolbox and whatnot anyway. I don't think I've spent anywhere near that much yet. I already had a lot of the parts I've used so far as well

    that is definitely the plan :D
     
  14. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    I started building the frame for the toolbox

    [​IMG]

    The area between the uprights is where the drawer will go. I put some flat bar in and screwed the draw slides to it

    [​IMG]

    I spent a butt-load of time measuring and working out the size for the drawer, and where the wheels would go in relation to the frame

    [​IMG]

    I used thick (12mm) plywood for the drawer so that I could safely screw into its edge (with a pilot hole drilled first). I also brushed on some PVA glue before joining with screws. The result was a pretty strong drawer.

    [​IMG]

    [​IMG]

    Fits my quads perfectly!

    [​IMG]

    I bolted a steel tab onto the rear drive section. Used bolts so I can easily remove it later

    [​IMG]

    Those tabs got welded to the frame

    [​IMG]

    I did a similar thing for the front as well, using the last piece of angle gal I had left over

    [​IMG]

    Obviously those joints alone are not enough to take much weight, more horizontal bars will be added across the top so I can put in some vertical bars to take the weight

    They were enough to give it a test run, however :)



    It drove flawlessly! It's a bit floppy without some reinforcement so I couldn't give it the berries but it'll be damn quick. The turning circle is pretty poor as expected, but I'm not really concerned, it'll be used out on open fields more than anything
     
  15. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Damn :mad: wires got tangled around the split-pin on the rear axle. Woops!

    [​IMG]

    Seems to have shorted and broken the motor somehow, it does nothing at all now :(

    Took it apart to have a look (very impressed with the build quality and design, by the way) but can't see anything wrong. Anyone know how I can test it?

    [​IMG]

    I used lead-free solder to re-attach the wire, hopefully to prevent it melting off if the motor overheats

    [​IMG]
     
  16. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    quick update. Sorted out the second motor, it was a break in the wire that I missed... obvious, duh, but I didn't check it....

    I started in on putting the carpet on the drawers. I didn't realise how thick the carpet would be when I built the drawer, so the added thickness meant the drawer wouldn't fit in the frame :rolleyes: I had to get the jigsaw out and trim it back.

    Drawer was disassembled and a single length of carpet put over the bottom and two ends. The carpet was glued down with spray on adhesive... good stuff

    [​IMG]

    The other two sides got covered separately

    [​IMG]

    Put the two sides in, did up the screws, then glued the carpet down over the screws to hide them

    [​IMG]

    Test fitted the drawer to the frame... success

    [​IMG]

    Using UPS batteries to weight it down while the glue hardens! The bigger sheet of plywood you can see in the back is the 'floor' for the toolbox section

    [​IMG]

    The floor fitted to the frame, and the top section of the frame welded in. The toolbox isn't that deep at all... but the length means it'll still hold all of my stuff

    [​IMG]

    Testing the load bearing capability... It's strong :D:D

    [​IMG]

    Started on the lid and soon I'll be cutting up the aluminium for the sides... this project is almost close to completion!
     
    Last edited: Feb 3, 2017
  17. mad_mic3

    mad_mic3 Member

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    looking sweet, I think you can use a multi meter to test, I'm not sure watt test to run but
     
  18. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Put the handle on the drawer and made some adjustments to get it to slide better

    [​IMG]

    The steering mechanism:

    [​IMG]

    It definitely fits in the boot of my car... just! I can even put the parcel shelf in

    [​IMG]
     
  19. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Still slow-burning this project along. I've spent quite a while waiting for a bigger sprocket to arrive in the mail to fix the lack of torque. Now that I have it I realised the motors weren't going to fit in their existing positions. I've spent a ton of dosh on this beast already so I built a new motor mount using only some metal offcuts I had lying around. Thankfully, I had plenty more #25 chain to work with and some more master links. Getting it all lined up is critical with chain drive systems and I've spent ages messing around lining up both motors, centring the sprocket on the axle, and getting it all perpendicular. Even with the chain appropriately tensioned, driving over bumps is enough to get it moving and cause it to come off so I'm looking into build a chain guide to keep it from going out of whack.

    [​IMG]

    While I'm sorting out the chain drive I don't want to paint the frame which is why I'm held up from finishing off the project. I did take it out last Sat though and it performed excellently. I had a roughly 300m walk with a heap of gear, a hexacopter, and lead-acid batteries. This thing carried the lot :leet::leet::leet: Plus I looked real cool doing it (my mum said :Paranoid:)

    When it's finished there'll be a lid on top, the lead-acid charge pack will be built-in, and the contents of the grey duffel bag would be inside the box. So only the blue gazebo would ride up top.

    [​IMG]
     
  20. don256us

    don256us Member

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    This is a really neat project. I like it a lot.
     

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