Drive Motor Sizing Tool | RobotShop Community

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tell th torque of each motor

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The torque for each motor we sell can be found on the product page on www.robotshop.com

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Thank you for this tool! Do the output(for each motor) refer to the free-run and stall torque? Or, are these values for a specific operating point?

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The torque value would what is required in that specific situation, and can be considered the maximum continuous torque. Based on observations and what motor manufacturers provide, the stall torque would be ~4x or 5x this value.

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Can you tell me why my result is different than yours?

Mass: 25 kg
Motors: 1
Wheel radius: 0.2 m
Velocity: 2 m/s
Incline: 0
Acceleration: 1 m/s2

You get:
Torque = 78 kgf-cm

I get:
Torque = (25 kg) x (1 m/s2) x (0.2 m) x (1/9.8 m/s2) x (100 cm/m) = 51 kgf-cm

Thanks.

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@Mitch Berkson Factor in 65% efficiency (that’s the default value), which gives 51 / 0.65 = 78.

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Or in this simpler example:

Mass: 1 kg
Motors: 1
Wheel radius: 1 m
Velocity: 0 m/s
Incline: 90
Acceleration: 0 m/s2

I would expect a torque of 9.8 N-m, but the calculator says 15 N-m.

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Thanks. The calculator and explanation are so well done that if you’re going to throw in an arbitrary number, it’s a shame not to mention it up front.

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Whoa. Now I see that you had efficiency as a parameter. Sorry about that. You can delete any superfluous comments I made.

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HI! I was building an Electric Wheelchair. And i calculated the output values required for the motor using this Tool. This tool is very useful. Can you please provide the formulae used in this tool to calculate torque, speed and power? Thanks

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@Amit Everything is in the tutorial: https://www.robotshop.com/blog/en/drive-motor-sizing-tutorial-3661

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@Coleman Benson I’ve read the tutorial provided, but I have 2 questions regarding the content.

#1 Can you explain in details what does the efficiency value stand for, and where should I look for it.
#2 Why didn’t you account for rolling resistance ?

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@Karol
#1 There are general losses in efficiency: DC brushless motors are not 100% efficienct, nor are the gearing to which they are connected. Batteries are also not 100% efficient, and there are also losses in cabling. The value provided would be a total of these losses. Since none of the parts are known until after choosing the products, we can only estimate a total efficiency.
#2 Honestly for simplicity, but if you can derive a simple equation using the input above, we’d be happy to add it.

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Hi. i need information about EMA actuators Application in Mobile Robotics

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@Rabea Unless we are missing something, EMA = electro-mechanical, which essentially covers all DC motors?

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Dear Coleman Benson
could you send to me your contect

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@Rabea For topics related to robotics, I can be reached at [email protected]

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Dear Coleman Benson.

I’m looking to make a hobby robot of max mass 10kg incline 30degree incline using 2 drive motors and all other parameters included the max torque your application gives me is about 300 ozf-in. i was looking to buy the pololu 100:1 or 50:1 motor set for better speeds however for 100:1 the specification lists the stall torque as 220 ozf-in. My question is how high is the stall torque supposed to be. ive read above that you said its basically 4x-5x the max torque listed by the application and in your view point which motor would be more suitable for me? the 50:1 or 100:1? please reply as soon as possible as i have a tight window to order this motor.

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@Mustafa Mirza If the sizing tool gives 300oz-in, the motor needs to have a stall torque of around 1200 to 1500oz-in stall torque. Neither motor would be suitable.

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Hi
The incline value…if I enter a value of 20 degrees and a desired Runtime of 20 minutes, is the provided value for battery capacity calculated on the basis of the 20 minutes having been at 20 degrees for the whole period? ie.the Extreme case of 20 minutes running uphill at 20 degrees?

lars