I’ve finally settled on a Final final project.
I’m going to attempt to make a soft robotic hand/arm thing.
I plan on having a laser cut arm structure, operated by servos and a 3D printed hand or grabbing device that will work as a soft robotics skeleton
The arm design is a modified version of this 2017 final project which is itself based on the MeArm . You can find a step by step on how to build your own, here .
I cut out all the parts I needed for my arm on 3mm acrylic with some minor modifications. I built a bigger box to be able to fit the vacuum pump that will be extracting the air of a vynil bag that will contain the 3D printed “skeleton” that will allow the contracting movement of the soft robotics. I also removed the claw component as well as any parts that are needed for said component since I’ll be replacing that with the soft robotics hand.
I call it a “hand” but I suppose ‘grip’ might be more accurate since the shape of the gripping device isn’t necessarily shaped like a hand. The idea came from these Origami-Inspired Artificial Muscles:
The principle is that anything inside a vacuum bag that had indentations that can act as mountains and valleys do in origami, when the air is removed from the bag that contains it, will be forced to contract to its fullest in whatever direction it’s set.
The uses are plentiful, as shown in the reference video.
I’ll try to do as many tests with as many designs as possible on that front as possible.
The first test for a skeleton was meant to be a kind of truncated cone, with pockets or indentations like this:
But despite using Filaflex filament, the thickness of the material was too thick to turn into a cone. This might have been because of the infill density (100%), but there might be other causes such as the absence of vertical pockets. In the end it wasn’t viable because the material had trouble giving way.
The second attempt was a play on the form of an actual hand, but similarly there was trouble with the print.
I reduced the infill amount to 50%, however, while this seemed to have contributed to the failure of the print, there was a problem with the positioning of the bed of the printer, as it was positions below the x-y home position and the pressure between the tip of the extruder and the bed wasn’t enough to allow the material to stick properly to the bed.
The third attempt was semi-successful and it is a simple “stepper” strip. The connections between steps was too short so I used my 3Doodler to fix it without having to reprint the whole thing.
When placed in the vacuum bag, and the pump is turned on, it should contract each once to the right and then to the left, and so on and so forth until it is completely retracted, lifting whatever it is attached with it.
The process with both bag materials was as follows.