Automotive How do I calculate required torque for two dc motors?

[Kaylin]

Hi,
I am doing a design project but I'm kinda stuck with choosing motors because i am not sure of the required torque. My project is a handicapped golf vehicle powered by 2 motors, so it would need to be able of climbing steep gradients.
I currently have an equation but I am not entirely sure if it's right.
It consist of :
1. Rolling resistance = (Gross Vehicle Mass) X (Co-efficient of Rolling Resistance)
2. Grade resistance = (Gross Vehicle Mass) X ( Sin(angle of max gradient) )
3. Acceleration force = (Gross Vehicle Mass/Gravity) X Acceleration
Adding all 3 up to give you Total Tractive Effort.

That's then used in the equation
Torque = (Friction factor for bearings and axles, etc.) X (Total Tractive Effort) X (Radius of drive wheel)

My question is, are these equations right or do I need to use more complicated equations dealing with moment of inertia, etc.

Thank you!

 

[jack action]

These are the right equations to use.

To take into account the rotational inertia, you only need to add a mass factor to the third equation. More info on this page.

 

[CWatters]

3. Acceleration force = (Gross Vehicle Mass/Gravity) X Acceleration

I think that should be..
Acceleration force = Gross Vehicle Mass X Acceleration

 

[Kaylin]

These are the right equations to use.

To take into account the rotational inertia, you only need to add a mass factor to the third equation. More info on this page.

Sorry for the late reply; but thank you.