I created the 3d printed flex extremities that can be used for arms or legs of robots. They are powered by a home vacuum cleaner and don´t use any electronic control, just the 3d printed analog pneumatic joystick is needed!
Each extremity is formed by 3 interconected muscles that also are the structure of it. They are distributed in a 120 degrees configuration, that let control the movements in 360 degrees of freedom, just by combining the vacuum / pressure input to each conduit.
In the center joystick we manage the air that comes from the vacuum cleaner hose, and from the vacuum cleaner pressure output. Depending of the position of the joystic it distributes + / - preasure simultaneously to each compartment. It has two pressure inputs and three chambers outputs. You can print one aditional joystick if you want to control another triple chamber extremity.
The force available depends on the power of the vacuum cleaner and the size of the compartments, but with a 4 inch compartment we can have a combined force of a few tens of pounds.
We have 3 compartments for each extremity that is connected by the 3 hoses to the joystick, it let us take analog control of its movements depending on the joystick position.
Step 1: Select the Size of the Model You Want to Print.
First of all you have to chose the size of the extremities, joystick controller and find a vacuum cleaner for power the system. This design was made with Autodesk Fusion 360.
Step 2: Print It!
Select ABS for the chambers and PLA or ABS for the Joystick. you can modify the size of this instructable for change the capacity of load and how much bending capacity is needed for your project.
Step 3: Assembling the Parts
For having an hermetic seal for the air, the model is designed for bonding the parts next to the assembly. For easier movement of the joystick you can lubricate with lithium grease all the surface of the center ball. You need to connect the vacuum to the inputs and air outputs for better movement control. When you bive vacuum the muscle contracts and when you give pressure it expands. The combination of pressures produce the controlled movement of the leg or arm.
Step 4: Operating the Extremities Chambers
Connect the vacum cleaner. Leave the joystick in it´s center position and power on the vacuum cleaner. Use the joystick in an intuitive way. Please check that the correct conduit is conected to the correct chamber, front with font, right with right and left with left. The big conduits correspond to the vacuum hoses, the one located next to the front chamber host corresponds to the vacuum host.and the one located betwin the 45 degrees chamber hoses, corresponds to the pressure input from the vacuum cleaner.
Step 5: What´s Next...
You can modify the inputs and output section of the joystick, depending on the chambers size you want, and the vacuum cleaner used. You can use a central vacuum system if you want, for using only vaccum input, leave the pressure input hose desconected as indicated in the previous step. You can have more chambers connected to the joystick if you want to have coordinated movements. You can use the chambers as legs, fingers or arms, all will have enhaced 360 controled movements.