Amount of torque required robot

[Mech327]

This is bad and I should know this but I can't seam to figure out if my torque calculation is correct.

Heres the story I am trying to build a robot that will run off of four electric motor one at each wheel. I want it to be able to weight around 25 lbs and be on around 6 inch diameter wheels or .25 ft radius . I want it to be able to run on a small amount of amps as possible and be able to go up a 30 degree slope.

The equation I used was at first to draw FBD and so 25sin30 = 12.5 which would be my force I would have to counteract. then to Torque = f X d = 12.5 X .25 = 3.125 ft*lbs of torque all together so divide by four .78125 ft*lb per wheel or .11kg*m or 11kg*cm which many of the motors are given in.

to me this seams kind of high because tried to compare to torque on a car. I know there are gears in transmission but still didn't add up with my calculations it would be as if the car couldn't make it up the hill that's why I am checking. Am I figuring it wrong that the motor would need that much torque to move it up the slope or what in the world am I doing wrong

Lastly if any of you out there ever built robot and have recommendation for motors let me know I want to keep each motor under 20 dollars but let me know

 

[LightHero]

It is difficult to provide a definitive answer without more information, such as the weight of the robot, the power requirements of the motors, and the type of terrain the robot will be operating on. However, your calculation of torque does seem reasonable given the conditions you have provided. You may want to consider other factors such as friction from the terrain, wind resistance, and the efficiency of the motors when deciding how much torque is required for your robot.