So I’m trying to create a 3 x 3 matrix of 3D printed cubes that can shrink or expand in size. The matrix will be able to shrink or expand due to actuators in between the cubes that can fold and extend its length. However I have not been able to find actuators that accomplish such a task. I need actuators that sorta mimic the function of the end of a straw. You know how on straws theres an end that get extend a little but it can also be bent and folded? Pop tubes are similar. They can extend and have enough sturdiness to support its own weight and hold its shape but when enough pressure is applied it will fold in on itself and shrink in length.
I basically need a pop tube actuator that can be controlled electronically. I’ve seen linear actuators, soft actuators, piezo electric actuators, and all sorts of others but haven’t been able to find anything quite like this. Do you know of any actuators out there like that? If not, do you have any ideas on how I can construct one of my own? I hope this question does not come off as too vague but I cannot continue on the project until I have the right components and parts. Any feedback will help thx
The biggest problem with the linear actuators is that they do not have the flexibility that would needed. When a whole group of them is shrinking and expanding, one of them might be slightly out of sync and will crack and break cuz the other ones will be ahead. They can't bend if they are slightly out of line are they will snap. They are also thick and cumbersome. The motor protrudes out from in front of the shaft and it makes it difficult to use
Letting one actuator handle the horisontal movement and another actuator handle the vertical movement, You might get somewhere. Lots of gears, chains.......
There is an entire field of research into the subject of compliant mechanisms and they can be made into a variety of shapes.
You will almost certainly have to DIY this. The problem is that if you want something small, then it becomes more difficult to work with. I'd suggest something like a balloon, or an accordion or bellows structure (just like a drinking straw) operated by pneumatics.
There's also nitinol muscle wire which was really popular about 20 years ago but seems to have fallen off the map. Using springs and muscle wire, you can make some really small actuators.
Each of your blocks has a center pin that extend though a slot in a fixed table. The slots are all oriented in line to the center of your fixed table.
Under the fixed table is a second table/plate with a spiral slot that is centered on the same center as the table above. Each of the block pin also extends into the spiral slot. Rotating the spiral table one direction will bring all block pins closer together. Rotating the spiral in the opposite direction will move ALL the pins further apart. All pins will be sliding back and forth in their fixed table slot and moving in the spiral at the same time.
Simple linear actuators would work provided there are hinges (or at least some flexibility) at both ends of the actuators (as there often are).
Hinges will allow considerable movement (that would damage rigid connections).
Rotational springs at each hinge will help keep the system centered (which would be otherwise unrestrained and unstable).
For example, if only actuator A extends, then B and C will just rotate a bit to accommodate the change in length of A. They won't "crack or break."
Likewise, if D retracts, then E (and D) will rotate.
Yellow = linear actuators.
Blue dots = hinges with springs.
Black squares = whatever.
Also, not all linear actuators are bulky. Consider....
or
Edit to add: this would also work in 3d, provided the hinges could accommodate that motion. Ball and socket or universal joint type, maybe. Or a rubber connector.
