can someone double check my calculations for the required torque to move a 1" wheel on a 60 Kg bot?
Here are my calculations:
I have a NEO motor:
Max RPMs: 5600
stall torque: 2.6 Nm
The gravitational force on the robot is 60Kg * 9.8 m/s/s which is just under 600 N pushing down on the robot.
Because there are four wheels, the force is split 4 ways, 150 N per wheel.
I am trying to drive a 1" diameter wheel on a gear train. The gear ratio is 43:7 from the driver to the idler, and 7:5 from the idler to the output. The wheel is connected to the output gear.
load torque = force * wheel radius so the load torque for each wheel is 150 N * 0.5" or 0.0127m = 1.91 Nm
because the gear train reduces the torque of the motor, a 43:7 and 7:5 increase the speed to 48160 RPMs and reduce the stall torque of the motor acting on the output to 0.3 Nm, not enough to overcome the 1.91 Nm required.
Therefore to make the motor have enough torque to make the robot move, putting the motor on an 8:1 gearbox increases the torque on the output to 2.4 Nm and decreases the speed to 6040 RPMs, definitely enough to drive the wheel.
Can someone let me know whether my calculations make sense and if they are correct? I’d really appreciate it! Thanks everyone!!!