Papers by Keyword: PZT Actuator

Abstract: A hybrid piezoelectric (PZT)/fibre optic diagnostic system has been developed for damage detection in built up composite structures. The hybrid system uses PZT transducers to actuate the structure and fibre optic (FO) sensors to capture the propagating wave. The diagnostic system will then have the advantages of both PZT and FO sensors. The applicability of the system is then tested for detecting an artificial damage at a skin/stiffener interface of a thick composite structure. The response of the FO sensors is then compared to PZT sensors and presented.

Abstract: Because of some intrinsic properties of the PZT actuator, such as hysteresis, creep and nonlinearity effect, it’s difficult to achieve satisfactory results and control precision for conventional PID controller. In order to improve the control precision of the PZT driven of micro positioning platform, we proposed a CMAC neural network based on PID control scheme, which has the characteristics of realizing feed-forward control and obtaining the inverse dynamic model of controlled object by the CMAC neural network controller, and realizing feedback control by conventional controller, which can ensure the system stability and suppress disturbance. Form MATLAB simulation results, it demonstrates that the CMAC+PID control algorithm can be able to improve the control precision and response time of the system, and enhance the anti-interference ability and robustness, comparing with the traditional digit PID control algorithms.

Abstract: To reduce the complexity structure of a flapping rotor, a piezoelectric transducer drive mechanism is designed to achieve active flapping and passive rotary motion. Then, its aerodynamic force model is built by using Theodorsen's theory in order to analyze the aerodynamic characteristics of this system. Model simulation and experimental results show that flapping amplitude, flapping frequency and initial angle of attack make a significant role for aerodynamic characteristics. The effectiveness of aerodynamic force mode also can be seen from the comparison of the results.

Abstract: The finite element model of a circular piezoelectric (PZT) unimorph actuator is set up, the static and dynamic characteristic of the circular PZT actuator are analyzed. For the investigated PZT actuator, comprehensive performance testing is carried out. Compared the simulation results of finite element method with experimental data, the central deflections of PZT actuator under the DC condition are same basically, the testing results show that the actual edge condition lies between clamped and pinned support. The impedance testing results of PZT actuators agree well with FEM analyses. Under AC condition, the central displacement which involves part of resonant component increases greatly by several times more than that under DC condition. While the displacement of actuator with resistance decreases greatly, and is slightly lower than that under DC condition. The relevant research methods lay foundation for the further study of PZT actuator under multi-field coupling condition. Key words: PZT actuator; Circular PZT unimorph; FEM; Static; Dynamic

Abstract: Lead zirconate titanate (PZT) ceramics are widely applied in manufacturing transducers, sensors etc [1-3]. In all of these applications, the PZT ceramic plates are bonded with a metal substrate making out to an actuator for generating a deflection. Large amount of research work has been done on investigating electrical properties [4-6] of the PZT ceramic plates, the influence of the environmental factors on their performance and mechanisms of electrical degradation phenomenon [7-9]. In this paper, two kinds of metal substrates (Kovar alloy and Titanium) are applied for bonding with the PZT ceramic plates. Experimental results show that, the materials of metal substrates are also severely influence the output deflections of the PZT actuators. In general, for both the two types of samples, they are with a better deflection at a higher working temperature, but the PZT actuator samples with Kovar alloy substrate is with better net deflection.

Abstract: This paper presents the concept of a compact hybrid sound absorber, based on a combined approach for sound absorption. A flexible micro-perforated panel (MPP) is used as the passive sound absorber for mid and high frequencies and a piezoelectric patch as the active control actuator for low frequency. The volume of this new absorber is highly reduced compare to conventional hybrid systems which employ porous layer as passive part and loudspeaker as active part. The vibration effect of the MPP in the hybrid system is also considered. Theoretical and experimental results show that the flexible MPP has the potential to dissipate more energy and can be utilized to improve absorption performance of the hybrid system by appropriately selecting its parameters.

Abstract: The dynamic models of the infinite cylindrical shell with integrated piezoelectric actuator are derived firstly in this paper, then, the total input power flow is calculated and expressed as the Hermitian quadratic form to act as the objective function to implement the control. The optimum set of secondary force is obtained by using feed-forward quadratic optimal theory, and the total input power flow with control was calculated for different locations of the actuator. The results show that different axial and circumferential locations will induce different influences on the control effect, and the results are greatly related to the vibration type and the circumferential mode.

Abstract: A double-chamber PZT micropump with two PZT actuators and three cantilever valves is introduced. When the PZT actuators work in anti-phase, the output performance of the pump is equal to that of two one-chamber pump running in series. Besides, the pump performance depends on the characteristic and geometrical parameters of the PZT actuators. A prototype double-chamber serial micropump is fabricated with the PZT membrane of 0.2mm in thick and 15mm in diameter. The pump was tested with water as the working medium. The testing results show that both the flowrate and backpressure of the micropump with two chambers running are about 1.54 and 1.8 times those with one chamber running, respectively. With two chamber running, the achieved maximum flowrate is up to 3.85ml/min at 50V and 150Hz, and the maximum backpressure is about 34.2kPa at 50V and 180Hz.

Abstract: To reduce the complexity involved in achieving the intricate motion and hence complexity mechanism, a new concept of Micro Flapping wing Rotor is firstly proposed to achieve active flapping and passive rotary motion. Secondly, aerodynamic analysis is made to understand schematic principles of this MFWR. Thirdly, parametric study (flapping amplitude, flapping frequency and initial angle of attack) using Theodorsen’s theory for lift prediction makes a significantly role for aerodynamic characteristics. At last, the prototype of a piezoelectric drive mechanism is designed and tested to compare the experimental data with theoretical values. The comparison shows that the lift prediction is closer to the experimental results.

Abstract: This paper presents the design of an embedded control system for insulin pump. The insulin pump is an integrated component in any closed loop insulin delivery system for type 1 diabetes. The pump consists of three main components: micro-needles, insulin reservoir(syringe), and piezoelectric (PZT) linear servo motor. The actuated syringe has an injection back pressure that resists the linear motion of the driving PZT motor. This back pressure acts as a disturbance and leads to in accurate position and consequently an imprecise insulin dosage. Therefore, a highly precise positioning control on the pump is required to control the insulin dosage and to maintain the blood glucose level in its safe range. The proposed controller is designed using fuzzy logic as a nonlinear controller to compensate any non-modeled nonlinear ities in the system.The embedded controller for the PZT motor can be implemented using FPGA or microcontroller chip. This controller acts as a slave and responds to its master controller which controls the complete closed loop insulin delivery system.