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In a development by Festo (BionicCobot), a rotary pneumatic actuator was used. enter image description here

It is also similar to Kinetrol vane pneumatic actuators. enter image description here

I have a question what is the formula for the torque of such an actuator depending on the pressure.

And are there any restrictions on the angle of rotation of such a drive?

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I can't really answer any questions on the Festo as they're not showing much in the videos. The yellow fellah is much simpler.

I have a question what is the formula for the torque of such an actuator depending on the pressure.

Torque is force by distance so in this case I suspect that you'll have to do an integral. Let's assume that the vane has constant width, $w$, minimum radius, $R_1$ and maximum radius, $r_2$. Pressure is $P$ (and is force per unit area in your chosen units).

$$T = \int^{R_2}_{R_1}Pwr\ dr = Pw\int^{R_2}_{R_1}r\ dr$$

If my maths is correct so far this shoult work out as

$$ T = \frac {Pw}{2}(R_2^2 - R_1^2) $$

And are there any restrictions on the angle of rotation of such a drive?

Yes. The yellow fellah is restricted to 90° as the vane will bump into the casting. The Festo unit will have similar restrictions.

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  • $\begingroup$ Are there any restrictions on the angle of rotation if you design a custom vane actuator? I mean that the actuator will work if its rotation angle is 270 degrees? $\endgroup$
    – Rooter
    Commented Apr 23, 2023 at 15:25
  • $\begingroup$ None other than it can't go full ircle. It'd say that about 330° would be the max. Any further and you're making a motor. The most common application for these vane actuators is for rotating ball valves which only require 0° to 90° to go from fully closed to fully open. $\endgroup$
    – Transistor
    Commented Apr 23, 2023 at 15:40
  • $\begingroup$ Ok, thanks.```` $\endgroup$
    – Rooter
    Commented Apr 23, 2023 at 15:50

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