Volvo FL12 8x8 Trial Truck

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Volvo FL12 8x8


I'm proud to present to you my best moc so far. I was building it for almost half a year. During this time I graduated, and my BSc thesis was about remote control of this vehicle.


Truck features all wheel drive, 4 wheel steering with different steering lock, full double wishbone suspension, remote controlled 4-speed gearbox with neutral gear, working winch, working fake R6 piston engine and working steering wheel.

Remote control

Vehicle is remote controlled by a mobile phone using Bluetooth connection. Both applications (mobile phone app and NXT app) are written by me in Java language (I used LeJOS to program NXT).



Gearbox uses 2 driving rings to shift gears, each of them is controlled by one NXT motor. After shifting gear motor locks in a fixed position to prevent slipping off a driving ring.

Gear ratios are:

  • gear 1) 18.75:1
    gear 2) 11.25:1
    gear 3) 6.25:1
    gear 4) 3.75:1

Steering system

Two front axles are steered with different ratios which is 1:1,67 (z12 drives z20). System construction is strong, backlash is low and it is impossible to desynchronize axles steering.


There is a price for this toughness. Steering geometry isn't perfect, but it's good enough:


Software provides "return to center" and "endpoints" functions, which means that wheels can't turn to greater angle than the chassis is design to.

The steering wheel inside the cabin is connected to steering motor via rubber, so the cabin can tilt along with the steering wheel.

Propulsion system

As you know NXT has only 3 motor ports, and I needed to control 4 independent motors. To resolve that problem I used HiTechnic IRLink sensor which control PF IR Tower. Propulsion motor (single PF XL) is connected to that tower. I had been forgetting to turn off batbox so I have attached touch sensor to batbox. Now NXT program checks before exiting if the batbox is turned on, and if so, NXT indicates it by sound signal.


There is a winch capable of lifting the whole truck. It can be switched on by red lever near the drivers seat. The winch can operate independently of shifted gear, so there is a possibility to change gears while using winch.


Volvo has double wishbone independent suspension on each wheel. Thanks to it truck is very stable and it's off-road capabilities are good.



Brickshelf gallery

Edited by Atr

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WOW! This is a mighty fine Trial Truck! :thumbup::thumbup: I like your use of the HiTechnic IRLink Sensor to control the multiple NXT motors. The hinged tarp makes it real easy to access all of the electronics, but it looks very natural. The mud flaps are a nice touch too :classic: What a great blend of TECHNIC, Model Team, and Mindstorms building!

Edited by dluders

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Excellent in every aspect!

I like the video.

You did nice job with the locking differential driving gears, so they wont slip off.

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I hope you received an A for your thesis. It's impressive how you integrated everything together and made it all work. The touch sensor reminder is a nice touch for battery life. Good work. :thumbup:

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Absolutely incredible! The work you've put into this is astonishing! If I had had a hat, I would've taken it off now. :thumbup:

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It really looks like and (almost) works like the real thing.

Great job! :thumbup:

Just curious... what's the weight of this wonder ?

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This TT is great ! The chassis is very well designed !

Congratulations ! :thumbup:

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backbone is right.

He has that knowledge because there is a topic on the polish forum ( with some more informations about Volvo in polish language.

Sorry for that I didn't translate all of the text.

I hope you received an A for your thesis

Yes, I did :)

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