Papers by Keyword: Piezoelectric Actuator

Abstract: The paper presents a circuit topology favorable to drive piezoelectric actuators for high frequency servo valve. It begins with a short overview of different energy-saving PZA drive types and their tradeoff between efficiency and circuit complexity. Then the mechanical structure and equivalent model of the piezoelectric servo valve are described. And the circuit topology including an energy-saving oscillator, an efficient DC bias power and a repetitive controller especially for tracking reciprocating motion, is proposed. The efficiency-improved PZA drive is then derived from the above design. Finally, the drive together with the servo valve is tested in the simulation experiments.

Abstract: This paper presents a new rate-dependent model for piezoelectric actuators. The proposed method directly utilizes a modified rate-dependent Prandtl-Ishlinskii hysteresis model to characterize the hysteresis and frequency effect of piezoelectric Actuators quickly and efficiently. To identify the model parameters, the least square method is adopted. Based on the identified model parameters, the rate-dependent model for Piezoelectric Actuators is established. By comparing the rate-dependent model with the real output of the Piezoelectric Actuators, the result shows that the new rate-dependent model could characterizes the hysteresis and frequency effect of Piezoelectric Actuator, which clearly demonstrates the effectiveness of the proposed Rate-Dependent Prandtl-Ishlinskii Model.

Abstract: By studying on the nonlinear hysteresis characteristics of piezoelectric actuators,this paper proposes a neural network modeling method based on polynomial fitting algorithm and a compound control method for compensation of the hysteresis.Simulation shows that the fitting error of neural network model is 1.42%. According to the developed hysteretic model,PID and feed-forward control methods are applied to the system.The result is that the tracking relative error of control system is 1.59%,so the tracking precision of system is improved significantly.This indicates that the neural network model reflects the hysteresis characteristics of piezoelectric actuators accurately,and this control method is an effective compensation control for hysteresis in piezoelectric actuators.

Abstract: Smart actuators, such as piezoceramic actuators, magnetostrictive actuators, and shape memory alloy actuators are widely used in applications of micrositioning and vibration control. Piezoelectric (PZT) actuators having the characteristic of infinitely small displacement resolution are popularly applied as actuators in precision positioning systems. However, the tracking control accuracy of the precision positioning systems is difficultly achieved because of its nonlinear hysteresis effect. Hence, it is important to take hysteresis effect into consideration for improving the trajectory tracking performance. In this paper, in order to capture the hysteresis nonlinearity in the PZT actuators, the Hammerstein model is put to use. The fuzzy control algorithm is used to identify the weighing values. The adaptive inverse controller based on adaptive fuzzy inference is used to track the PZT actuator. We firstly identify the weighting values of the Hammerstein model in situ using the multi-mode fuzzy control algorithm based on the error between reference displacement and actual displacement of the actuator, and then calculate the weighting values and threshold values of the Hammerstein model. Finally, we obtain the feed-forward input voltage. The stability of the controller in the presence of the estimated state is demonstrated. The experimental results show the performance is effectively improved under the intelligent control method.

Abstract: Recent advances in measurement systems require positioning systems with high stiffness, accuracy and speed. Piezoelectric actuators which are featured with mechanical simplicity, quick response, and electromagnetic immunity, are often used in precision positioning. It is known that piezoelectric actuators can achieve high positioning accuracy by the stepping mode but low speed. By contrast, the resonance vibration mode will offer high positioning speed, but sacrifices the high inherent position resolution. For the stepping mode, the displacement of the piezoelectric actuator significantly affects the speed, of which larger displacement induces higher speed. For the resonance vibration mode, an elliptical motion of the piezoelectric actuator tip is generated by horizontal and vertical eigenmodes, and the optimal efficiency can be achieved when the two eigenmodes are operated at the same frequency. For the applications of high positioning accuracy and speed, a piezoelectric actuator should be designed by taking these two operation modes into consideration simultaneously. Based on these requirements, the optimal structural dimensions of a piezoelectric actuator are obtained using a genetic algorithm.

Abstract: In this paper, the optimum design and dynamic analysis of a new type of piezoelectric Braille display cell are studied by computer aided engineering software. At first, the design parameters of piezoelectric actuator are analyzed by finite element method to determine the position of fixed end and minimum voltage to actuate 0.7mm displacement and 15g output force. Then, the optimum design is performed according to the electric displacement 0.7mm, output force 15g, actuator length, position of fixed end and minimum voltage. Finally, Braille display cell is analyzed by dynamic simulation software. It shows that actuators take 0.0002 sec to upward achieve 0.7 mm displacement. The result of optimum design is reasonable in this paper which can be the reference for related research.

Abstract: Increasing demands regarding the light-weight, high-torque and high-precision actuator are inducing the need for new actuators and new drive principles. This paper introduces a novel principle for transforming the linear motion of high performance piezoelectric actuators into continuous rotation is implemented by two piezoelectric actuators acting on a driving gear covering a driven gear with a slightly smaller diameter. By driving the piezoelectric actuators, the driving gear is energized to move on a circular trajectory around the driven gear which is thereby slowly rotated. Firstly, the structure and driving mechanism is introduced. Secondly, transmission ratio, the demand driving force and displacement are analyzed theoretically and by the means of simulation analysis. Finally, the bottlenecks of mechanism design and machining are presented. Some instructive reference for the structure design of Piezo/Gear compound drive is provided.

Abstract: This paper describes the design, construction, and analysis of a new piezoelectric actuator design for small aircrafts in the special requirements of the steering weight. It describes the working principle of piezo actuator, optimizes the piezo chip specification parameters by experimental measurements, put forward the finite element analysis simulation and the experimental testing of piezoelectric actuators’ drive performance. The simulation and experimental results show that the new design meets the design requirements of weight and space control.

Abstract: A new non-contact liquid bearing, which utilizing traveling waves, is developed in this paper. The developed bearing is designed in an octagon shape where series of piezoelectric actuators are placed between a rigid support plate and the elastic thin bearing surface around the circumference and in the radial direction. The driving apparatus for the developed bearing is implemented based on DSP and voltage amplifiers. The liquid film force induced by traveling waves is confirmed by experiments which prove the feasibility of the developed bearing.

Abstract: The active vibration control of the flexible cantilever beam with PZT actuators was studied in this paper, and the principle and the method of the active vibration control were analyzed. First, using the balanced reduction method to reduce the model was carried out; the reduced model would be controlled. The placement of the piezoelectric actuators was utmost important, the optimization arrangement of the piezoelectric actuators was studied in this paper basing on the modal influential matrix of the piezoelectric actuators in order to make it to maximize its effectiveness to realize active control. Next step the LQG/LTR method is used to control the structure, then the LQR method was adopted to control the beam, and the two methods were compared. The results show that the LQG/LTR method to control the beam will realize effective control if only the treatment is adequate, when the acoustic noise and Interference were added to the system.