Blake Hannaford and his colleagues at the University of Washington are about to release a flock of medical robots with wing-like arms, called Ravens, in the hope of stimulating innovation in the nascent field of robotic surgery.

The Raven — originally developed for the American army by Dr Hannaford and Jacob Rosen of the University of California, Santa Cruz as a prototype for robotic surgery on the battlefield — is compact, light and cheap (relatively speaking) at around $250,000.

It is also the first surgical robot to use open-source software. Its Linux-based operating system allows anyone to modify and improve the original code, creating a way for researchers to experiment and collaborate. Universities across America are taking delivery of the first brood of Ravens in February.

The research-oriented Raven has not yet been approved by the FDA for human surgery, so investigations are, for the moment, restricted to operations on animals, or on human cadavers.