| With the development of material science, computer technology, signal processing and control theories in recent years, smart material structures has become one of the most active study field. Smart material structures are special composite structures, which are integrated by smart sensing element, smart actuating element and micro control unit. It is widely used in the aerospace, national defense, automobile, mining, industry robot, machine tool and other industries. After suggestion and investigation by American army, Japan, England, Germany, Australia and South Korea, the research progresses attract many scientists who spend a lot of money on the research work of smart material structures. Since 1990's, many Chinese scientists have also obtained many achievements in this field.The active vibration control of smart material structures is just based on the actuating and sensing effect of the smart materials. Piezoelectric materials have been made into piezo-actuators and piezo-sensors due to their inverse piezo effect and direct piezoelectric effect. Piezoceramics have been used successfully for many years in the field of vibration control, owning to its high forces into the range of kilo-newtons and short reaction times in the order of a few microseconds. The early studies are mostly focused on the method of gluing piezoceramics on structural surfaces, which has some disadvantages such as difficulties to protect the ceramics and the connection wires, bad coupling with only one surface glued on the base materials, low signal-to-noise ratio etc. These problems can be solved using the embedded piezoceramics, and furthermore, the piezoceramics can be placed in the optimal positions, especially in the optimal deepness for the piezo-actuators, according to an optimization algorithm before they are embedded, so the actuator effects and sensor signals are thereby enhanced. This dissertation deals with the active vibration control strategy using the embedded piezoceramics as both actuators and sensors. With several ceramics embedded into the composite material structures during the manufacturing process without knowing the structural behavior in advance, this dissertation makes use of a self identification procedure to get the models of the system. Apparently, the on-line self identification method enable people to update the models of system. The main research works done and conclusions extracted are listed as follows.(1). Based on the piezoelectric equation, the strain and stress distribution are analyzed for the composite material structures with piezoelectric materials embedded inside. The actuating and sensing abilities for the embedded piezoceramics are discussed in details. Consequently, the actuating equations, when piezoceramics work as actuators, and sensing equations, when piezoceramics work as sensors, are derived.(2). Two kinds of modeling methods, finite element method (FEM) and experimental identification methods based on modal analysis theory, are applied to get the models of the dynamic systems. Using the finite element model for the composite material structures with piezoceramics embedded and the technique to reduce the number of degrees-of-freedom of FEM model, a reduced and appropriate model for online control is also introduced. The modal parameters are identified using the experimental identification methods, and the state space model of the dynamic system is built up using the identified parameters. The identified model is more suitable to make online control due to its small size.(3). Linear quadratic regulation method is used to design the optimal feed back controller for the composite material structures with the piezoceramics embedded. After analyzing the functions of the weighting matrices Q and R, an efficient method, which is very easy to calculate with clear meaning, to select Q and R is proposed. Without iteration process, this method can save computational time considerably. The required feedback states are estimated by full states observer, where the poles of the obse...
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