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associated with it containing a function (see Figure 1) which determines if the
TLR gets triggered and by what amount. PAMPs, in terms of robotics are sig-
nals received by the robot's proprioceptive sensors (TLRs). These can trigger the
TLRs starting the immune response in order to prevent possible damage in the
long run. For example a temperature which exceeds various predefined thresh-
olds might trigger responses designed to limit or prevent damage. In the natural
innate immune system the action of TLRs leads to the generation of an inflam-
matory response via a number of pathways and mechanisms. This response is
initially characterized by the generation, accumulation and diffusion of cytokines
through the local tissues and into the bloodstream. In the longer term, continued
inflammation results in a sustained “stress response” which has wide-ranging and
diverse effects at a number of levels. This can affect physiological responses, be-
haviour and psychological state. These responses might vary from protection of
an inflamed area, to the reduction of use of a limb due to localized pain through
to increased sleep periods in severe cases. These varied responses can be incorpo-
rated into an innate artificial immune system with the help of the SOM. This can
be achieved by activating the SOM using the current state vector of the robot
(represented by the states of activation of all TLRs in the robot) and respond-
ing appropriately to affect the high-level controller, by releasing hormone into a
neuro-endocrine controller for example. Whilst not implemented here assignment
of remediation activities to particular nodes of the SOM (such as specification of
which hormone to release) could be achieved automatically by examining which
components of the robot are the source of the inflammation and selectively sup-
pressing control system components which access those components. In the first
instance this is a reasonable assumption, but in those cases where this response
is insucient to prevent further inflammation the SOM can be used to “spread”
the inflammatory response to neighbouring nodes in order to suppress activity
of components in closely related states. The gradual spreading of inflammation
through the SOM ensures that the dependence on “engineered-in” relationships
between component failures and remediation activities is only used in the first
instance. When such relationships are incompletely or incorrectly assigned, the
spreading to other closely related remediation activities improves the likelihood
of an appropriate response being elicited in a computationally inexpensive and
extensible manner.
Response 1
)=
{
. . .
Response n
f(TLR
x
Response 2
. . .
TLR1
TLR2
TLR3
TLR4
TLRx
Fig. 1.
Schematic of the TLRs' functions
