Machines making other machines: new twist on self-replication

Oct 03, 2005 feature

How can we best build self-replicating machines? The past few decades have witnessed self-replicating virtual automata, ranging from the benign Game of Life by Conway to malicious computer viruses. Self-replicating physical constructs are, however, currently both delicate and rare. The work of mathematicians such as John von Neumann and Roger Penrose, around the birth of automata theory in the middle of the past century, revealed no limits in principle to constructing such devices. The main obstacles appear to be the substantial engineering challenges.

Engineers at the Massachusetts Institute of Technology recently tackled a key challenge: how can a machine replicate properly if its components appear at random? Living cells face a similar problem when duplicating their DNA from randomly diffusing chemical components. To address this issue, the group fabricated a simple self replicating machine that dealt robustly with randomly available input components.

The MIT design consists small robotic blocks which link to one another using actuated hooks. A specific ordered linkage of blocks makes up a correctly formed device. A large number of individual blocks sit on a low-friction air-table, which shakes to move them about randomly. Each block carries both sensors to identify blocks around it and a program specifying which blocks to attach to and which to ignore. Blocks which pair correctly by chance stick together, while incorrect pairs fail to stick. With appropriate rules, certain structures can catalyze the formation of equivalent structures out of the random blocks. Thus correct structures that initially appear by chance will duplicate exponentially in a positive feedback loop.

A key requirement for this engineering approach (and indeed for living cells) is good error control. Living organisms, for example, utilize clever chemical and kinetic techniques for minimizing errors in their copying processes. Incorrectly incorporated blocks in the MIT setup are excised using a clever set of error detection and correction rules. The total rule set is surprisingly small, making this work a nice demonstration of self-replication in the face of environmental randomness. This work paves the way in principle for smart materials which can self assemble into structures of interest, with minimal assistance on the part of humans.

by Joe Levine, Copyright 2005 PhysOrg.com

Explore further: Former Brown dean whose group won Nobel Prize dies

add to favorites email to friend print save as pdf

Related Stories

Key building block of life may have come from deep space

Nov 14, 2014

Researchers at UH Mānoa's Department of Chemistry have provided compelling evidence that glycerol, a key molecule in the origin of Earth's living organisms, may have occurred in space more than 4 billion ...

Japan scientists make see-through mice

Nov 06, 2014

Researchers at the RIKEN Quantitative Biology Center in Japan, together with collaborators from the University of Tokyo, have developed a method that combines tissue decolorization and light-sheet fluorescent ...

Cell division, minus the cells

Oct 30, 2014

(Phys.org) —The process of cell division is central to life. The last stage, when two daughter cells split from each other, has fascinated scientists since the dawn of cell biology in the Victorian era. ...

Recommended for you

Former Brown dean whose group won Nobel Prize dies

4 hours ago

David Greer, a doctor who co-founded a group that won the 1985 Nobel Peace Prize for working to prevent nuclear war and who helped transform the medical school at Brown University, has died. He was 89.

Revealing political partisanship a bad idea on resumes

8 hours ago

Displaced political aides looking for a new, nonpartisan job in the wake of the midterm power shuffle may fare better if they tone down any political references on their resumes, finds a new study from Duke University.

Laser from plane discovers Roman goldmines in Spain

8 hours ago

Las Médulas in León is considered to be the largest opencast goldmine of the Roman Empire, but the search for this metal extended many kilometres further south-east to the Erica river valley. Thanks to ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.