Hello all !

This is my first post here and I would appreciate your help.

I am trying to find suitable motors for a four wheeled robot and doing the following calculations:-

Robot Characteristics
==============

weight(w)=50 kg
wheel diameter(d)=8 inch=0.2032 m ==> wheel radius (r) = 0.1016 m
required velocity (v) = 1 m/s
required acceleration (a) = 0.1 m/s^2
inline angle=0 deg
no of wheels = 4
expected efficiency = 0.85 ( 85 % )


Calculations
=======

required force (F) = m x a = 5 N
required Torque (T) = F x r = 0.508 Nm
required Torque per wheel (Tw) = T/4 = 0.127 Nm
required torque for 0.85 efficiency Tw=0.149 Nm ==> Tw_kgf= 0.0152 kgf-m
required rpm = (V*60)/(pi*D) = 93.989 rpm ==> rps= 1.567 rps

I have been told by my supervisor that these calculations are not correct.

I cant figure out what I am doing wrong ...