Chapter 2. Prehension

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Computed activation
of arm muscles
Signals to arm muscles
96 THE PHASES OF PREHENSION
Left and
Right
Orient
Maps '
..
. k Adjustable
weights
Left Retina Right Retina Left Eye Right Eye
Muscles Muscles
\ I v
Visual seZation of
cylinder on retina
Signals indicating current
activation of eye muscles,
one for each eye muscle
Figure 4.13 Kuperstein's (1988) model of adaptive hand-eye co-
ordination. The visual system consists of two 50x50 receptor
retinas being controlled by six muscles for each eye (three pairs of
antagonistic muscles). The arm system consists of a three degree
of freedom shoulder and two degree of freedom elbow being
controlled by ten muscles (five pairs of antagonistic muscles).
Fixed algorithms convert the exteroceptive and proprioceptive
visual information into inputs for the adaptive neural network.
The network associates the visual pattern with an arm configu-
ration, and adjusts the weights in order to reduce the error between
the computed values and actual ones. Only 12 of the 318,000
connections are shown between the internal visual representation
and the motor representation.
on a left and right retina modelled as two arrays of 50 by 50 receptors.
In the figure only two of the 2500 receptors are shown for each retina.