Pivot Design Notes

Setup ratio as either $3\cdot 2\cdot 2.66=15.96$ $3\cdot 2\cdot 2\cdot 2.66=31.92$ $3\cdot 2\cdot 2\cdot 2\cdot 2.66=63.84$ (Fits but only if you delete redundancy)

22mm dead axle pivot 1/2” dead axle intermediaries with needle roller bearings (17.5mm OD)

lightened and assembled:

Optimal ratio calc

• $m=1.36kg$ (3lb) mass at $l=0.2m$ (8 inches) from pivot
• motor torque at zero rpm ${\tau }_0=4nM$ (x44)
• motor free speed ${\omega }_{\tau \to 0}=7530\cdot 2\cdot 60=903600\pi rad/s$
• gearbox ratio $r$

Center of mass:

$$I=m{l}^2$$

Angular Acceleration:

$$\tau =I\alpha$$ $$\tau =m{l}^2\alpha$$ $$\alpha =\frac{\tau }{m{l}^2}$$

Torque as a function of speed and ratio: $\omega$ is the angular velocity of the output, so it needs to be multiplied by the ratio to function properly

$$\tau =r\cdot ({\tau }_0-\frac{{\tau }_0}{{\omega }_{\tau \to 0}})r\omega$$