If I have a bot that is 60 lb (27 kg) and I want it to be able to push something 80 lb (36 kg) at 5 mph or 420 rpm with the wheels I have,
Does it seem acurate that I would need a motor with only 3 Nm torque?
I did not find this stat to be accurate but that is what the robotShop calculator told me
Please advise
Thanks
You want to create a robot which will push a dead weight of 80lbs, or carry a weight of 80 pounds?
If it’s a question of pushing (like in sumo combat), then the calculator will not work, and you’ll have completely different calculations to do.
The important part will be calculating the “resistive force” which involves the area of contact between the object and the ground, its weight, and the coefficients of friends between the two.
I was told that in order to find the motor that best fits my robot I would best be suited using robotshops, drive motor sizing tool.
However after further inquiry, I was told that if I was going to be using the bot to push a heavy weight then I would need to do completely different calculations.
Can anyone tell me what said calculations would be? Or point me in a good direction?
Specs
wieght 60lb desired speed 7.3 ftps( 420 rpm with wheels with 2" radius) push an object 80 lbs+
Thanks for any help
softschools.com/formulas/phy … ormula/92/
Note that to get the block started, you would need to use the coefficient of static friction.
Your next step is to know or calculate the coefficients of friction.
Knowing the force required horizontally, you then need to link that to the drive wheels and the force they exert on the ground.
robotshop.com/blog/en/drive- … orial-3661
In your case, the angle will be near zero.
Note that the calculation above is per wheel, and there is an additional component F to move the block which acts at the center of the wheel.
The other approach is to simply over-design the robot and “you get what you get” in terms of pushing power.
