Biologists Discover Cellular Bang-Bang Controller

Posted 19 Nov 2008 at 20:57 UTC by steve

A robots.net reader sent us a link to a Princeton news release describing research by Raj Chakrabarti and others on cellular proteins that act as adaptive machines, guiding biological evolution. Our reader notes, proteins configured as bang-bang controllers steer random mutations in deterministic directions; robot navigation algorithms as a mechanism for self-directed evolution. A bang-bang controller is a simple algorithm that bounces between two extremes like a household thermostat. This type of control is commonly used in robotics and, it now appears, is an integrel part of every living cell. The cellular bang-bang controller guides random mutations in a way that corrects imbalances, even repairing mutations that disable the controlling protein chains. This is also fascinating to anyone who appreciates cybernetics. It's a great example of a cybernetic feedback loop, much like a centrifugal regulator on a steam engine. This disovery is likely to make some waves in the field of evolutionary biology as it suggests a cellular mechanism guiding the way the cell responds to natural selection. Will it make waves in robotics as well? I doubt it will make anyone throw out proportional control, but I wonder if we'll see bang-bang being favored in biomorphic robot designs? You can read more about this research on Raj Chakrabarti's home page where you can also find a copy of the full paper, "Mutagenic evidence for the optimal control of evolutionary dynamics" (PDF format).