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Torque Calculations

  1. Oct 1, 2004 #1
    Hello Everyone,

    I am a programmer and I am working on an application that can do torque calculations for some motor simulation models that I am working on. What I have is a torque data file wilh data representing the amount of torque on a wheel at a given degree of it's rotation (so if I had 360 lines of torque data, then there would be a number representing the amount of torque for each degree of rotation as the wheel spins 360 degrees around). What I would like to do is to create an application that will create a realtime animation showing how the wheel would move and behave with the given torques on the wheel using the data that I have. The user will have to input any necessary paramiters like the mass of the wheel, friction on the bearings, initial starting position, and any initial force that is applied. Could someone give me an idea of where to start calculation wise to do this? I basically want the program to make the wheel accelerate and declerate based on the torque information and paramiters that I input into the program. Any help/assistance will be greatly appreciated.

    Jason O
  2. jcsd
  3. Oct 1, 2004 #2
    I would start with Tau = I * Alpha ( Moment of inertia * Acceleration ), but before doing that you will need to get the net torque due to external forces and subtract/add it from/to this torque and then use basic equations of motion once you have the Alpha value. Hope this helps.
  4. Oct 1, 2004 #3


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    So, you have a data file listing various values of [tex]\tau (\theta)[/tex]

    The user submits numbers for bearing friction, mass and initial position, [tex]\tau_{fr}, ~m, ~\theta _0 [/tex]

    From the mass and the wheel geometry, you calculate the moment of inertia of the wheel, I. Then you use the equation that Gopi suggested. This gives you
    [tex]\tau (\theta) - \tau _{fr} = I \frac {d^2 \theta}{dt^2} [/tex]

    Solve this differential equation numerically, and use the initial condition [tex]\theta (t=0) = \theta _0~~to~get~~\theta (t) [/tex]
  5. Oct 5, 2004 #4
    Thank you both for the help! I'm going to have to sit down with this one to do it so I'll report back to you two soon if I have any problems. Thanks for the equations and explanation!

    - Jason O
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