[ODE] Torque settings for simulated servo

[Garvin Haslett]

I am using ODE to simulate a robot that I am building.  To model the 
servo motors I am using hinges but I seem to be making an error in 
setting the servo torque.  I have set gravity to -98.1, thus implying 
that one unit of distance is 10cm.  I have chosen my unit of mass to 
be 0.1 kg.

The data sheet for my servo lists the torque as being 4.1 kg cm or 
0.041 kg m.  I convert this to Nm by multiplying by 9.81 giving 0.402 
Nm.

I seem to be getting lost in choosing the correct unit of torque in 
simulation.  I've taken the view that a real Newton is the kgm/s^2 so 
therefore one of my simulated "Newton" shoud be 0.01 N (0.1m x 
0.1kg).  Continuing this logic my unit for torque should be 0.001Nm so 
my the value I set the Max Torque for my servo should be 402.

However once I do this I find my simulated servo lifting weights the 
real one cannot.

Is there any obvious flaw in my reasoning here?

Thanks in anticipation of any help,

Garvin.