The term nanorobotics is used quite often by science fiction authors. They are imagine a software controlled mini robot swarm who is able to do useful things. The main idea behind nanorobotics is, that it is working with the same principle like the large scale EV3 brick from Lego mindstorms.. That means, on the microcontroller a program is started which is equal to the Artificial Intelligence and the programs controls the robot.
Unfortunately, this vision is wrong. Real nano machines are not realized by programmers, but by meccano like principle. A meccano machine is an all mechnical device which doesn’t need software. A typical large scale example are knitting machines which are able to produce a rope. This principle of a software-less fabrication can be shrinked down into the nano level. That means, the enginees have no demand for a subatomic microcontroller which is programmed in Forth, but what they need is a mechanical blueprint which is working by it’s own.
What does that mean? Suppose a large scale assembly line is built with the normal meccano set. It contains of motors, gears, boxes and lots of metal. If the production line is ready we can put at the left the input material and get on the right the result. The machine is working by it’s own. The difference to a robot controlled system is, that no decisions are made during the production. It is not a problem from Cybernetics or control theory, but it is a mechanical design problem. A nanofabrication system works with the technology from the 19th century. That means before the computer was invented and before the first computer algorithm were created.
The question is, what is the potential of such a nanoscale production line? The limit are the same like for real meccano. What can be automated with mechanics can be realized on smaller level too. What is not possible are everything which has to do with decisions. That means, if some optimizing problem has to be solved, meccano will fail. That means, it is hard or impossible to realize with meccano like structure a thinking machine, better known as a computer. That means, if some sort of game is there on the subatomic level, similar to pacman, it is not possible to automate it. In a game, the player must take decision. This is the field of Artificial Intelligence, and Artificial Intelligence needs per sure a computer for execute the software.
The question which has to be answered by the engineers is how to transform game like problems into a non-software problem which doesn’t need a decision but can handled autonomously. repetitive automated manufacturing systems are sometimes described with marked graph. It is a decision free system in which the road to the goal is predifined.