Nonlinear Dynamics Based Sensors - A New Class of Devices for System Monitoring

Post-silicon materials like polymers and solution-based devices allow to design new types of sensors. On the other hand, the nonlinear dynamic behavior of a class of nonlinear circuits offers the possibility of conceiving devices where the nonlinearity of the circuit is exploited to realize new mechanisms or improve classical ones. In this PhD work we discuss the possibility of coupling a new class of materials with nonlinear dynamic circuits to design a new class of sensors. The results that are included are preliminary and cover a wide range of applications. In particular advanced sensors based equipment has been studied on an electromechanical system, in order to monitorize its vibrating behaviour to establish self organizing phenomenon to control the system. 1 STAGE OF THE RESEARCH The research regards with the study and the characterization of a new class of sensors based on coupling the performances of new materials, like polymers, and the behaviour of nonlinear electronic circuits. The proposal of using this sensors for monitoring complex self-organizing electromechanical systems is a second step of the research. At this time, the sensors have been realized and characterized. The self-organizing electromechanical system has been realized by using different architectures. Preliminary qualitative measurements have been performed. 2 OUTLINE OF OBJECTIVES In this project the coupling between new materials and nonlinear circuits will be explored to design a new class of sensors. The principle is to link the variation of a quantity detected by the material to the change of a parameter of a chaotic circuit, so that to exploit the parameter sensitivity of chaotic circuits. A proof of concept will be given in this study, by using a type of innovative material/device, such as Clevios P HC V4, IPMC and water solution cells. The principle will be demonstrated with a series of experiments that pave the way to a more intensive characterization of the devices proposed. The variation of a quantity, such as humidity, hydratation level or bending, will be here shown to lead to significant changes in the dynamical behaviours of the circuit (in particular, a Chua’s circuit will be used), that is, the dynamical behaviour of the nonlinear system bifurcates as a result of the sensing (Fortuna, Frasca & Xibilia, 2009). Although the principle may be applied to a variety of materials, it is particularly interesting when applied to newly conceived materials which as such may at a preliminary stage of development , or characterization, yet they can be successfully used with such approach. Moreover, the proposed devices will be adopted for monitoring a complex electromechanical system, in order to make advanced studies in self-organizing complex systems.