The Investigation Of FBG Nonuniform Strain Sensing And PLZT-IPMC Non-contact Compound Actuating Performance

With the rapid development of research work in aviation, aerospace and large civil engineeringsystem, more and more technical requirements in both of structural health monitoring (SHM) andshape control technology have been raised. Recently, the research no matter on stress and strainanalysis derived from the sensing-model of fiber Bragg grating (FBG), or the shape control ofconstruction based on non-contact photoelectric actuating technology, have important practicalsignificance.In this dissertation, on the one hand, the inverse problem of reconstruction of nonuniform straindistribution profile along the axial direction of FBG is researched. The main contents andachievements are as follows. Firstly, the property of FBG strain sensor is reviewed, and the discussionare focused on the detailed precedure of transfer matrix (T-matrix) method, Runge–Kutta (R-K)integrating method and modified transfer matrix (MT-matrix) method for grating reflected spectrumcalculation. Secondly, the optimization performance of particle swarm optimization (PSO) algorithmand its improving algorithm are analyzed deeply, and a novel approach is presented to reconstruct theaxial nonuniform strain profile distribution of FBG based on T-matrix method and dynamic particleswarm optimization (DPSO) algorithm, which the axial strain of FBG is optimized by DPSOalgorithm, the optimal solution is searched by constrainting the error between the calculated reflectedspectrum through the T-matrix method and the target reflection spectrum, and the inertia weight of thealgorithm is adjusted dynamically according to the distance between individual particle and the globaloptimal particle in current population, as a result, the convergence speed to optimal position isaccelerated. The simulations reveal that the designed method has higher reconstruction precision thanthe quantum-behavior particle swarm optimization (QPSO) algorithm when the strain profiles issupposed to linear, quadratic, sine and discontinuous. Thirdly, the influence of evolutionary generation,bandwidth and sample margin of reflected spectrum to the reconstruction precision of DPSOalgorithm are discussed in detail. Finally, the T-matrix method is replaced by the MT-matrix method tocalculate the reflected spectrum, and the DPSO algorithm is applied to simulate reconstruction of thefour types of strain profiles reconstruction mentioned above. Moreover, the testing equipment isdesigned to measure the FBG reflection spectrum which is acted as the target reflection spectrum, andthe strain profile distribution is reconstructed by the DPSO algorithm. Both the simulation examplesand experimental results verify the feasibility and validity of the designed method. On the other hand, the photoelectric non-contact actuating technology is studied by experimentalway in this paper. Firstly, the physical characteristics, actuating mechanism and mathematical mode oflanthanum-modified lead zirconate (PLZT) ceramics and ionic polymer metal composite (IPMC) filmare indicated and analyzed. Furthermore, the experimental tests on photostriction effect of PLZT andelectro-mechanical characteristics of IPMC are performed respectively. Finally, the experimentalresearch for non-contact compound actuating performance is accoplished. The photovoltaic voltagewhich is produced by the PLZT ceramics when it is subjected to high-energy ultraviolet lightillumination is used to excite the bending deformation of IPMC film, meanwhile, a overvoltageprotection circuit is designed to prevent the IPMC film from being broken down under the highvoltage. The test results show that the non-contact compound actuating technology is effective andfeasible.