I am honestly surprised that you wrote all that just to help me. I sincerely appreciate it. You did not judge or tell me to drop the idea (as other members of other forums have done). You clarified several points that I had doubts about.
Right now I am ready to buy the motors (Stepper Motors). Can you take a look at them so you can give me your opinion? I want to avoid losing money and buying what can work.
The arm will have 4 actuators:
2 actuators on the shoulders (3 Nm): https://www.amazon.com/-/es/23…ino-Router/dp/B00QG32Y86/
1 actuator in elbow (1.9 Nm): https://www.amazon.com/-/es/st…9oz-driver/dp/B0781GNX8W/
1 actuator on the wrist (0.46 Nm): https://www.amazon.com/-/es/bi…-impresora/dp/B06XSYP24P/
In case of lack of strength I plan to use a speed reducer to increase the torque (as you said, it will be slower). Either a toothed pulley or gears.
The arm will measure a total of 100 CM (light material, like plastic, for now that will be test, then it will be carbon fiber). That is, 0.5 m from the shoulder to the elbow, and 0.5 m from the elbow to the wrist.
Let's say you only need to lift 2 kg (I know you need to calculate the weight of the motors and material, but let's say it's 2kg).
2 kg = 19.6 N
Torque = Force x Distance
T = 19.6 N * 0.5 m = 9.8 Nm
Note: that last was what I thought so far, but according to your formula it is different, with the engine torque (3 Nm / 0.5m = 6N). Please correct me if I have any mistakes.
My questions are:
1- Does that mean that I need to increase the torque of my motor by 3 Nm? How much more should it increase?
2- What do you think of the stepper motors?
Btw, I will be careful not to leave the motors frozen in X position when not in use. Thanks for that information, it was super valuable.
I will value other data like that. And... I value everything you wrote. Thank you.