13/06/2023, 20:31, still Tuesday.

Soooo....

Anyway, I was having second thoughts about the exosuit/mechsuit.

So, you basically have two options with the power of the exosuit/mechsuit:

1. You have 900 watts of power, with 300 newton meters of torque and 30 rpm, with 300 kg of force that will be lost in the distance from the axis of rotation to the point of the limb, giving you a maximum of 100 kg of lifting force . However, the legs would not be able to support the user's weight + the weight of the load.
2. You have 900 watts of power, with 3000 newtons meters of torque and 3 rpm (3cm per second), with 3000kg of force that will be lost in the distance from the axis of rotation to the limb, giving 1000kg of lifting force, but in a meticulous slow speed.

However, if you convert the RPM of a 1cm diameter shaft into linear velocity, you will obtain 1.5cm per second and 60,000kgfcm of torque (30,000kgfcm if it is 2cm in diameter, with 3cm per second of speed).
However, if you change the diameter of said shaft to 4 cm, and therefore the linear velocity to 5 cm per second, the rpm to 15, and the torque to 600 Newton meters, you will be able to lift 3,000 kg, and therefore 1,000 kg . 

I say this because 5cm per second is roughly how much your biceps move to fully lift the arm (I think), *if* I directly translate that to the mechanical arm, it would be able to lift 1 ton with 900 watts of power per " member of the Stewart platform".

I would keep the same mechanisms like the winch/winch linear actuator and so on.

This means that the mech with 1 ton of lifting capacity would only use 900 watts of power.

Of course the legs would need to lift 3 times that, so if you add the 900 watts of the arms and torso, that would be 2700 watts of power in total, plus 2700 per leg, that would be 8100 watts in total, giving the 10.8 horsepower needed for make this move.

If you add an extra 1 ton to the legs to lift the whole thing, each leg will consume about 5,400 watts of power, giving 13,500 watts in total, which would give 18 horsepower.

Of course, the weight would be distributed over the whole body, i.e. 900 watts on both arms to lift 1 ton, plus 900 watts on the torso and 5400 watts on the legs, giving 7200 watts in total, i.e. I would only need 9,6 horsepower.

And since, I assume, I would lose around 20% of power due to inefficiencies, I would need 11.52 horsepower, or 8640 watts.

Around 2 extra horsepower (1400 watts) to compensate.

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I hope I did the calculations correctly this time.

And yes, I feel guilty that I didn't keep trying, it's almost an obsession.

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Edit¹:

Just now I noticed that I inputed 30 rpm instead of 15 in the calculator, if it was 15 rpm, it would give around 3cm per second of linear speed.

This means that, again, I misscalculated.

If it was 30 rpm instead of 15, the wattage would double.

So, instead of 900 watts per limb and 9.6 horsepower in total, it would be 1800 watts per limb and 19.2 horsepower in total.

And one would need 3.84 extra horsepower to compensate inefficiencies, assuming these are only 20%.

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Still, it would be 5cm per second, it would move really slowly.

It would even be worth the trouble?

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Edit²:

By the way, the same can be applied to the reverse:

with 10cm of diameter, 30rpm and 300 newton meters, you would only be able to lift 300kg with a speed of 15 cm per second, and thus, only 100 kg of force at 3 times the length of the limb.

You would need 10 times more torque, and thus, 9000 watts of power per limb in order to achieve 3000 kg, and thus, 1 ton at 3 times the length of actuation.

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I just woke up and all the calculations are messy in my brain.

In the torque calculator, it states that at 5cm of radius, and thus, 10cm of diameter, one would be able to lift 30,000 newtons (3,000 kg) with 1500 newton meters of torque, which would give 15cm per second of linear speed at 30 rpm.

Which would need 4713 watts if you inserted 1500 newton meters and 30 rpm on the horsepower calculator.

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Edit³:

I totally forgot about the mechanical advantage of the pulleys/winches/hoists in the image above, but while calculating the mechanical advantage (aka putting into online calculators), I got a little bit confused with the final result.

You see, if I where to put 3000 newtons (300kg) of force in a 20 cm long lever, which would be a 40cm diameter disk/pulley/hoist, I would be able to lift 30,000 newtons (3000kg) in a shorter 2cm long lever (a 4cm diameter disk).

However, when I insert these values to a torque calculator, it gives me 600 newton meters of torque, with 30rpm, would be 1800 watts of power.

But if I put 1200 kgfcm in a kgfcm to newton meter converter, I get 120 Nm of torque, which with 30rpm, would give 300 watts of power.

Meaning that if I attached a 4cm diameter electric winch to the tip of a 20cm long lever/40cm diameter disk with a rope, I would need actually just 120Nm of torque to lift these 3000 newtons (300kg).

So, or I'm misunderstanding something and reaching to the conclusion of 300 watts of power per limb, or the torque calculator is correct.

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This bugged me all day, but I forgot an essential part of the problem: the rpm through the reduction ratio.

The 4cm winch drives a 40cm winch with a reduction of 10:1, so, for every 10 rotations of the small one, the bigger one would rotate 1 time.
And so, the torque would multiply 10 times also, so this means that I would still need 60 Newton Meters, not 120 and an RPM of 300, not 30 to be input on the bigger wheel using the smaller wheel.

Meaning that in the entire system, there is still 1800 watts being used and transformed through the reduction ratios.

The way I was interpreting this was that I would need to input 600 newton meters on the outside of the outer winch/hoist, which such number is the output of the mechanism.