Optimization Design Of Control Parameters And Configurations For Piezoelectric Structures

Structural shape control is an important application of piezo-intelligent materials. The study on structural shape control with different purposes and requirements using piezoelectric materials is one of the hottest issues. The structural configuration (such as size, shape and location) and control parameter (voltage) are important factors that affect the control performance. The study on method of concurrent design of piezoelectric actuators and their control system to achieve desirable control performance and economic benefits has potential application value.Structural optimization is an effective tool to achieve rational and efficient use of materials and to make the structures have better mechanics and multidisciplinary performance. Base on the idea of optimization design, this dissertation presents investigations into structural static and dynamic control of piezoelectric structures considering control cost; the development of topology design model for piezoelectric actuators and energy harvester; the mass detection sensitivity analysis for piezoelectric biosensor. The main contents are given in the following paragraphs:(a) Design optimization of actuator-controller linkage for structural static and dynamic shape control. This dissertation focuses on the design problem of shape control of composite plate using piezoelectric stiffeners. The parametric description of linkage between the actuators and voltage channels (independent control parameters) is presented. A concurrent design methodology of actuator linkage and control parameters is developed. To deal with the special optimization problem with discrete variables (description parameters of linkage) and continuous variables (controlling parameters) coexisted, an optimization scheme based on simulated annealing algorithm is developed. The proposed optimization formulation can achieve desired control effect by using limited voltage channels, which not only reduces control cost and operation difficulty, but also keeps control precision.(b) Simultaneous optimization of control parameters and configurations of actuators. Besides control voltage, the configuration of actuator is another important factor that affects the control performance. In this dissertation, both control parameters and configurations of actuators are treated as design variabes. Optimization models for structural static and dynamic control considering control precision and cost (energy consumption and piezoelectric material used) simultaneously are proposed and corresponding optimization schemes are develop. Desirable control performance with given control cost and minimization of control cost with allowed control error are achieved in the numercal examples.(c) Topology optimization of actuators considering the distribution of piezoelectric driven components. Piezoelectric micro displacement actuator is one of the key technologies in the field of precision machinery and precision instruments. It is of great significance to study the design methodology of piezoelectric micro displacement actuators and enhance their driven performance. The optimization model simultaneously optimizing the distribution of piezoelectric driven component with fix geometrical feature and layout of flexible mechanical structure is studied. By combining topology description function method which formulates the driven component and RAMP (Rational Approximation of Material Properties) material model which formulates the layout of flexible mechanical structure, topology optimization model of actuators considering the distribution of piezoelectric driven components and corresponding optimization scheme are developed.(d) Topology optimization of piezoelectric energy harvester under stochastic excitation. The novel technique that extracts energy from environment vibration and provides energy sources for the microelectronic devices has attracted much attention. It is significant to study piezoelectric energy harvesting technique and enhance its work efficiency. Since the ambient vibration sources where the energy harvester is deployed to are often in random vibration, it is desirable to design energy harvesters under random vibration. The layout of the piezoelectric energy harvesting device is determined by using topology optimization method. Topology optimization of piezoelectric energy harvesting device under stochastic vibration is studied. In the present optimization formulation, the distribution of the piezoelectric materials and the location of the mass layer are treaed as variables; the energy harvesting performance is considered as objective function. The corresponding optimization scheme is developed.(e) The mass detection sensitivity analysis for piezoelectric biosensor. Piezoelectric biosensor is one kind of sensors whose adsorbed target molecules can be detected by monitoring the mechanical resonance frequency of the structure. The adsorption of target molecules causes a change in the sensor's mass, which in turn causes a shift in the resonance frequency. The detective accuracy is strongly depended on mass detection sensitivitiy which is defined as resonance frequency shifts per unit mass change. The mass detection sensitivitiy of the piezoelectric biosensor is related closely to the size of its sensitive part. The mass detection sensitivity analysis for cantilevered piezoelectric biosensor is studied. The calculation of mass detection sensitivitiy is derived theoretically. The dependence of mass detection sensitivity on structural configuration parameters and resonance modes is examined through numerical examples. This work is supported by the High-level Government-sponsored Oversea Study for Postgraduates, the National Basic Research Program of China (Nos.2006CB601205 and 2011CB610304), the National Natural Science Foundation of China through grant Nos. (90816025 and 10721062), the Major national science and technology projects (2009ZX04014-034), the Research Fund for the Doctoral Program of Higher Education of China (No.20090041110023). The financial contributions are gratefully acknowledged.