01 - Design
The goal of InflatiBits is to provide quick, easy and fun tools for building your own soft robotic structures with minimal effort. To reach this goal we split standard soft actuator designs into their core components, that serve as building blocks which can be freely combined to create a wide range of soft actuators.
Below is an overview of the basic building blocks:
Extenders
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Extenders are fabricated from soft silicone with an internal zero volume air chamber. and air-inlets/outlets at the top and at the bottom. They extend in one direction, when inflated. The footprint of the extenders is compatible with the Lego grid.
Air Connectors
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Networks, stacks and arrays of Extenders are interconnected through Air Connectors such as flexible and rigid tubes, y-connectors and plugs. Syringe pumps can be used to manually control the system pressure.
Rigid Restrictors
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Rigid Restrictors can be used to create mechanical connections between the Extender modules to modify their linear expansion behavior. They attach to the grommets surrounding the Extenders and cannot be stretched or bent.
Bending Restrictors
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Bending Restrictors can be made from air Tubes and two end caps. They can't be stretched, but are bendable and also attach to the side grommets of the extender chains.
Sliding Restrictors
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Sliding Restricors allow for controlled extension of the Extender up to a certain length. This special type of restrictor is made from a flexible plastic stick with a fixed mechanical connector at each end, and one or several sliding elements in between.
02 - Fabrication
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Extenders consist of two identical halves made of silicone rubber that are joined together to form the final module. The silicone for each halve is poured into its individual two part mold (with inserted rods to achieve clean holes). Both halves are then glued together at the end of the curing process with the same silicone.
Air connectors, as well as all rigid restrictors can be machined on a turning lathe from acrylic rods.
Bending Restrictors consist of a piece of tube and two end caps made from machined acrylic rods or 3D printed parts or a combination of both.
Sliding Restrictors consist of 3D printed caps connected by plastic filament.
For Details on the materials used, see the Bill of Materials.