The aim of this work was to design a control system for the shape memory alloy (SMA)
actuator operated airfoil (a cross section of wind turbine blade). Design of SMA control is focused
on the reliable operation of the SMA actuators. The actuator should follow the targeted shape
accurately and without too much delay. Another objective is to avoid overheating which is the most
critical damage to the structure. SMA actuator shape control is in principle possible to do with any
position control method, but the specific properties of the SMA actuators, like the hysteresis, the
first cycle effect and the long term changes, need to be taken into account.
In this work, a wing profile prototype was measured using optical fiber sensors and traditional
strain gauges. Also, external laser sensors were used to measure displacements of upper/lower
surface and trailing edge. Shape change was obtained by embedding SMA wire actuators into fiber
reinforced polymer (FRP) composite structure. SMA actuators were laminated in such way that
bending of trailing edge is always downwards. Actuators are activated with Joule heating and the
temperature is measured with integrated thermocouples and optical fiber temperature sensors.
As a result, this work gave information about the usability of optical fibers sensors in active FRP
composite structures. Measurements also give information about the efficiency of SMA actuators in
shape control of relatively stiff FRP structures.
Two characterizations of hypercubes are given: 1) A graph is a hypercube if and only if it is antipodal and bipartite $(0,2)$-graph. 2) A graph is an $n$-hypercube if and only if there are $n$ pairs of prime convexes, the graph is a prime convex intersection graph, and each intersection of $n$ prime convexes (no one of which is from the same pair) is a vertex.
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