New Piston Shock Servo Driven


Working on a new piston shock borrowing the "twizzler" gear from Inmoov's shoulder/bicep design. Im going to make a my own piston rod but for test purposes im using his for now. The shock itself runs off of a standard size servo. The piston rod twists INSIDE the shock rod as seen in the video. Im going to print it tomorrow and see if my idea will work. Ill share the results here. This would be a great addition to the neck of the inmoov for starters.


curious to see the results. I wonder if there will be too much friction with the outter tube length.

How does the worm gear "twizzler lol" connect to the servo output shaft?


Hi Anthony,
I like the concept of your linear cylinder. There are similar linear motor designs which work real well.
My question is can you incorporate a "flexible extension rod" (similar to an R/C push rod in a tube)? This would allow the linear movement to transfer over a slight arc, or allow side thrust movement. This could work in a shoulder without binding in the output end of the cylinder. What are your thoughts?
I enjoy and look forward to your future robotic developments.



I will be getting my hands on a commercial linear motor this weekend to play with. I need to test it by using two relays for extend and retract. If it works well I will see what sizes are available in lower dc voltages (24vdc). I will let you know how I make out.



@Anthony.... How are you going to implement positioning feedback? I don't see a way of using a external potentiometer in your simulation... That servo will need to rotate several times in order to move the piston full length (that is if you want an greater mechanical advantage over that of a regular servo's output) ... This means the servo will need to be hacked or you'll need a 360deg servo... Problem with both cases is you don't show a way of position feedback....


I used a "pull wire pot" on linear projects in the past. It works like a tape measure which winds a multi turn pot as it extends and retracts. It was a cheap way to monitor locations. It would also work if you moved in an arc or even 90 degrees (using a pulley).


Edit: Check out Andy Mark, item am 2618 $17.00 usd basic part. Complete kit $40.00 usd. You could 3D print your own housing or incorporate into cylinder design. Concept only?


Linear motor example from ebay. Weight may be an issue?

In the industrial equipment projects I used to build, I liked off the shelf items if they fit. I felt it was easier to buy than build. No offence intended to Anthony. I think his designs and motivation is fantastic! His builds are Great!


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I picked up the parts to build a simple linear pot. I will build a test sensor and I will post results.