??? Add all the forces resulting from routes passing through node I to determine
the overall communication force FcommI .
Step4: For each node I the forces generated by the goals, obstacles, restoring
forces, and information forces to find the overall force acting on node I.
Step5: For each node I Update the mobile position I based on a discretized
version of mass-damper model di?®erential equations.
Step6: If iteration number k is a multiple of No, perform a global rerouting
to reflect the fact that the protocol may change the routing scheme as the
sensor nodes reposition.
Step7: If the node positions change by less than the positive ???small??? scalar
", exit, otherwise repeat Step2.
6.1 Considerations of energy consumption
Considerations of energy minimization are important in ensuring the maximum
lifetime of the MWSN. In a typical mobile robot equipped with a wireless
radio, the node energy consumption due to computation is measured in the
microwatt range, to communication in mW to hundreds of mW range, and
to motion in hundreds of mW to tens of W range. The larger the size of the
robot, the more likely it is for the motion energy expended to exceed the
energy required by communications, and vice-versa. One way to reduce the
energy consumption is by making the node damping coe?±cients vary with the
amount of energy expended:
vi(t) = v0(1 + kviEi(t)),Ei(t) = Z t
0
Fi(?? ) ?™ ri(?? )d??. (15)
If the robot node damping increases with expended motion energy, or
alternatively, it decreases with the amount of on-board energy available, the
robot speed decreases accordingly.
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