Linear Extension Sensor (LEX) in a 'Humaniform Muscle'.
The quest to develop robotic arms based on nature has led
Merlin Systems in Plymouth to develop a linear extension sensor
and a 'humaniform muscle'.
The linear extension (LEX) sensor is a multi-mode sensor. It uses
opto-electronics to measure absolute position but it can also be used
to measure other parameters like velocity and acceleration.
The on-board processor and memory also allows data to be logged.
The LEX sensor is an integral part of the humaniform (human-in-form)
muscle, a lightweight actuator which operates pneumatically.

As air is allowed into the muscle the braid expands radially and contracts
axially which causes the muscle to shorten. Internal air flow control system
means any muscle length can be maintained with minimal extra energy input.
The LEX sensor forms part of the internal feedback system which maintains
the length no matter what load or pressure the muscle is under. has been
that they've been "One of the problems very difficult to control," with air
muscles previously explained Dr Mark Norman, Merlin's chief executive.
"But by putting sensors and air flow control systems~ inside the muscle
we've made them very easy to control."
When the muscle is operated at a pressure of six bar it is capable of
delivering a contraction force of 4kNew-tons which, according to Norman,
outperforms a human muscle.
Norman sees the LEX sensor, which is already being produced, being
used in automotive and automation applications and replacing linear
distance transducers and linear potentiometers.
The humaniform muscle, which will be available starting in January,
will find use in robotics, automation and as prosthetics.
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For more information, contact:
Merlin Systems of Plymouth, UK
December 2000