Servers by jDrones

Almost there but need a bit of motor help


(Ennalta) #1

I have been on quite the build and I need just a bit more help.

Instead of using the custom industrial motor I was going to use, I am taking the whole ‘brain’ and simply putting it into an rc car first to test everything out. However I’m not sure what to do about motors, how I should wire them up, etc. and I have not been able to find any good guides to help me. Here is my set-up:

  • Pixhawk 2.1 with Rover 3.2.0 beta 2
  • U-blox Here+ GNSS
    I purchased a skid steer/tank RC device that has two basic brushed motors in it figuring this would be the easiest way to go.

Power is currently a 3600 mah 7.2v venom nimh battery running through the Spektrworks Power Brick Mini

Now my questions:

  1. should I use these motors or…
  2. use something else such as a servo (I have a couple of MG 996R) and driver (stepstick) combo ?

Either way, how do I wire it up? I assume I can use the 12.8v lithium ion battery (or use the system battery) but again, not sure how to wire that up.

Any help would be greatly appreciated.


(Thomas J Coyle III) #2

@ennalta,
Start here
Regards,
TCIII AVD


(Ennalta) #3

Appreciate that, but that’s has been by bible for the last few weeks. I haven’t seen anything in there that addresses my particular question.

I guess the closest that I get is that I need to wire to 1 and 3 but that’s about it.

EDIT: I do appreciate the second link. Have not seen that yet.


(Thomas J Coyle III) #4

@ennalta,
Did you read about the skid steering tuning here?

I assume that the tank motor ESCs (Electronic Speed Control) can provide both forward and revers directions and that they have R/C PWM inputs that are compatible with your Pixhawk2.1 servo outputs?

The ArduRover firmware assumes that you are using the right joystick for both throttle (elevator channel) and the steering (roll channel).

Here is a skid steering wiring diagram that uses a PX4IO board but the servo outputs to the motors are the same. However you might need to use Servo 2 instead of Servo 3. You will have to experiment.

Regards,
TCIII AVD


(Ennalta) #5

Thank you Thomas @TCIII . Yes, I did read through that tuning tutorial but I’m not even to that point yet.

At this point I’m jsut trying to figure out how to physically wire up the motors and which ones to use.

Can I use the DC motors? Do I have to use a servo? Will the servo I have work? Do I need to run it straight into Pixhawk or do I need to run it through a stepper driver first.

I’ve built massive robots, but nothing this small so I don’t really understand the RC world, acronyms, etc.


(Ennalta) #6

Sorry @TCIII I don’t see any links to a wiring diagram.


(Ennalta) #7

Never mind, I am totally screwed. Apparently hidden in the secret RC black magic manual is a thing called an ESC which I never even heard of until today and now I have no idea what to do.

This project is going to be the end of me.


(Thomas J Coyle III) #8

@ennalta,
I have edited my previous post to add a link to the skid steering wiring diagram.

It does not matter if your skid steering motors are DC or Brushless, however they must provide forward and reverse to function correctly with the firmware. The skid steering ESCs have to be compatible with the Pixhawk2.1 servo outputs.

Regards,
TCIII AVD