about the torque calculation of a mecanum wheel

[zhy557]

hi everyone,
I'm new here and interested in the mecanum wheeled robot. I have read the torque calculation document from Ether, in which says the actual force (along the roller axis) is Fc=1.414T/r, T is the torque of motor.
But in the article "kinematics and dynamics modeling of a mecanum wheeled mobile platform", can be found at "http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=4749608&url=http%3A%2F%2Fie eexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber% 3D4749608" , it is saied that Fc is one component of T/r, means Fc=0.707T/r. Some other articles also say so.
The above is what confused me. Could anyone try to explain it or do I just understant it in a wrong way?
PS, I do want to konw how does the force Fs (vertical to the T/r) come out.
Thank you a lot.