alphaCentaur

01-21-2014, 11:34 AM

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 ...

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 ...