Revision as of 17:14, 20 May 2022

The idea here is a class of self replicating pick and place robots

• that do not produce their own parts but instead use parts pre-produced by a different process
• that do assemble copies (and improvements) of themselves from the same types of parts that they are themselves composed out of.

Base block materials the design is aimed at

Reusable crystolecules

The design is:

• particularly targeted towards reusable fully passivated crystolecules as the pre-produced base parts.
• not targeted towards partially passivated crystolecules that get irreversibly welded together to bigger microcomponents.

Foldamer parts?

Pre self-assembled foldamer parts with high geometry might eventually work too as base parts.
Given they are stiff enough. But this is questionable. If it works it will be quite a bit bigger than in the crystolecule case.
Unfortunately the parts that structural DNA nanotechnology can make are almost certainly not stiff enough.

Macroscale prototypes

For prototyping functionality at the macroscale FDM 3D printing or resin 3D printing are possible options.
Of course one needs to keep an eye on: Applicability of macro 3D printing for nanomachine prototyping
Look at mechanical property transposition for comparability.

Eventual macroscopic use cases of the system (as home device beside a RepRap or as a device for truss construction in space) can't be excluded but optimization for those applications is definitely not the design goal here. heavy chains instead of drive belts and other design choices might make the system quite sub-optimal for those alternate application cases.

Key properties

Same as the ReChain frame systems that may serve as a basis.

Narrow range of part sizes

All parts are in a narrow size range.
There is not a range from very small connectors to very big plates.
Instead bigger parts are made up out of many smaller parts
This allows to keep all assembly activity to just a single (the second) assembly level.

No dependence on friction based self holding

A dedicated nanoscale friction element

• is more like a tuning fork that distributes its excitation by it's anharmonicity (deviation from linear restoring force)
• is solely used for deliberate energy dissipation not friction self holding. It swerves a different purpose.

There is no friction at the nanoscale between atomically precise surfaces in the way as there is friction at the macroscale.
So screws won't hold in the same way as they do at the macroscale.
Matching up atomic surface waviness can hold things in place but that's a energetic snap holding not friction self holding.

Bulky design

There are a few reasons for bulky design.

• To compensate for the low stiffness of all materials at the nanoscale.
• To make sure all the parts can be handled with robotics of only one (the second) assembly level. Giving a narrow size range between smallest and biggest parts.
• The design happening at the lower end of the physically possible size scales. Details see below.

On bulkiness originating from designing on the lowermost physically possible size limit

When the functional crystolecule pieces are already at the lower end of what physics allows for, then pieces for connecting parts together cannot by yet smaller since this would make them smaller than an atom. This pushes the size of the connection mechanisms and similar up into the size scale of the parts they connect. This is very much unlike the macroscale where e.g. large pieces are often held together by screws, splint rings or other means that are quite small in relation.

A note on selfreplicativity

While with "second assembly level self replication" there is a medium compact form of self replication present
the self replicative capability is not as compact as in the case of the molecular assemblers approach.
Molecular assemblers are outdated because of too compact self-replications and the consequences thereof.

Choice of name

The name RepRec was chosen in analogy to the name RepRap (Replicating Rapid Prototyper)
that refers to partially self replicating 3D printers.

The name "RepRec" is:

• a shorthand for "Replicating Recomposers".
• a name for a whole class of robotic systems (akin to RepRap not referring to one specific 3D printer but a whole class of them)

Related

• ReChain frame systems – A factored our sub-projects
• Second assembly level self replication
• Applicability of macro 3D printing for nanomachine prototyping
• Self replication

External Links

https://reprap.org/wiki/RepRec_Pick_%26_Place_Robots
There more kept in the context of usage at home in conjunction with a RepRap
which is actually not the primary design target.