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3600 Pound 1:1 RC Car

Old 09-25-2016, 09:53 AM
  #1  
heiniac
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Default 3600 Pound 1:1 RC Car

I wanted to share my project


I bought a Chrysler Voyager 94 3.3l V6 4x4, and converted it into a drivable remote controlled car!


(There will be a video of it in the bottom of the post)




Here's the car finished:





Here's the car before I painted it:



Looked like a boring small family van. That's why I painted it.
I used normal house paint, no grinding, just washed the car, and I was totally impressed by the result! The paint is even sticking nicely to the windows




Anyways! Saying a little bit about the system.
I used a Spektrum DX18 controller, and a AR9020 receiver.
But here's where it gets complicated, the signals does not go to motor controllers, instead all the signals from the receiver, goes into an arduino microcontroller. The microcontroller processes the signals, and controls the motor controller. The motors have a potentiometer/ position sensor, giving feedback to the microcontroller.
All summed up, the microcontroller compares the signal from the receiver, with the sensed position of the motor, and from there chooses which way the motors spins/pushes/pulls.


WHY use a microcontroller?
This way, the wheels will always follow the position of the stick. It's much easier to fine tune, do expo, add safety functions, and overall operate. (But a pain in the ass programming:censored


Here is a picture of the control case, it might look overwhelming, but it's just my wiring being a mess





There is a arduino mega, handling all the important functions as steering, brakes, gas, and gear. Then there's an arduino uno and a relay board controlling auxiliary functions as lights, horn and so on. There is three 40A H-bridge motor controllers to power the motors. They get a PWM signal from the microcontroller. I also have an additional uno for throttle cut safety.


I was planning on designing and etching a custom pcb for the car, but that is a whole project at its own.




Throttle system:
For the throttle system I used this servo motor pulling the throttle valve in the engine bay.






I had problems with unintended acceleration, and after a LOT of fuzz, I found out that the motor twisted when I started/gave a little gas, and therefore the wire from the chassis mounted servo motor became too tight, which resulted in the valve to open, which resulted in more twist from the engine, which gave even more gas... SO! The solution: Mount the servomotor to the motor, not the chassis. Worked like a charm. The picture was from before i moved it to the motor.






Steering:
This took a lot of time, and I had to learn welding.. The motor I used for the steering, is this geared 12v 5,8nm 100 rpm electric motor. I welded a mounting frame next to the steering column. I screwed the motor to the frame, and put a bicycle gear on it. I took another bicycle gear, splitted it, threaded it around the steering column, and welded it. I also added a tension wheel to the chain drive, and a steering position sensor / 10 turn pot.


















Brake system:
The brake system consists of a heavy duty electric 12v actuator with 100kg of force which is WAY more than needed. It's mounted to the underside of the steering column, and uses a fork to push the brake pedal down. This way, it's also possible to manually brake. The actuator has a sliding potmeter on the side to regulate braking.









Gear system:
For this project I HAD to choose an automatic. Or else it would take an eternity. The way the different gears are selected, is by pushing or pulling a wire, coming from the gearbox. Different lengths corresponds to different gears. (D N R 3 L)
So I made a mounting plate for the wire and an actuator, pushing or pulling on the wire. This system is very similar to the brake system, it uses a actuator to push or pull, and a sliding potentiometer / position sensor to signal the microcontroller on where to start and stop the actuator, and which direction to go.













Ignition:
The ignition consists of three relays, bridging/shorting out the correct cables coming from the ignition. Luckily for me there was no immobilizer system.










Safety functions:
If the system looses signal, the brakes are applied 100%.
I have a separate microcontroller, cutting the throttle unless there is a valid signal from the controller.
There will be a separate RF system with pneumatic emergency brakes later.




Final notes:
The reason i chose the flight controller over the normal car controller, is because i needed a lot of functions/switches. Here is a list of the functions I'm using:


* Gas - Brake : Stick
* Steering : Stick
* Off - Acc1 - Acc1&Lights : lever
* Starter : button
* D-N-R : lever
* Park : lever
* System: Off - On - On+Servomotors active : lever
* Ignition cut safety : lever
* Horn : button
* Strobe lights: Off-Mode1-Mode2 : lever
* Future auxillary : lever






To sum up, the car is drivable remote controlled, or normally. I can do speeds up to 100 MPH, but I never tried, and would not recommend it


I am kind of finished with it now, and I have no idea of what to do with it. Be shure to leave some ideas!



Here is the video I made, enjoy!
https://www.youtube.com/watch?v=YhDS1ZqTYso

Last edited by heiniac; 09-25-2016 at 01:01 PM.
Old 09-26-2016, 08:44 PM
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Mechanicaloverlord
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Very cool. Why do it? Sometimes you have to just because you can! Perfect way to compete in a demolition derby without getting hurt!
Old 09-27-2016, 02:57 AM
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Mudgy
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Mate that is just fantastic ! Great work. I can appreciate the time taken to problem solve and create your components. BIG JOB.

Awesome !!!

Cheers, Mudgy

Last edited by Mudgy; 09-27-2016 at 02:59 AM. Reason: typo
Old 09-27-2016, 05:37 AM
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heiniac
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Thank you guys! It's true you sometimes do it because you can, but also for the fun of it! I had to twist my head around lots of problems that came up, but with a littlebit of patience, i managed to do it

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