From Ken Green
Your report “No walkover”
(15 April, p 14)
seems to illustrate yet another
case of scientists not fully understanding the matter they are pursuing.
Standing and walking are not a matter of co-ordinating the actions of many
muscles. The problem of bipedal motion is one of constantly adjusting the body’s
position to keep the centre of gravity above the points of support—the
feet.
To do this we control the joints at toe, ankle, knee, hip and vertebrae by
using information sent from these points, as well as inputs from those
little-understood sensors, the eyes and inner ears. The servo action required is
not a steady affair, but a successive approximation.
I agree that to achieve this by strap-on electronics is a very tall order,
even when the researchers are fully aware of their problem. It takes us more
than six years to learn to walk safely—let alone run—when we have a
whole body. Such experience is all but impossible to design.
Tintagel, Cornwall
