Sang Zhiqian

Bio: Sang Zhiqian is an academic researcher from Hangzhou Dianzi University. The author has contributed to research in topics: Jet (fluid) & Hysteresis. The author has an hindex of 2, co-authored 11 publications receiving 13 citations.

A new hysteresis modeling and optimization for piezoelectric actuators based on asymmetric Prandtl-Ishlinskii model

Abstract: Piezoelectric actuators are core components in micromanipulation systems in the field of biomedicine. The asymmetrical hysteresis of piezoelectric actuators greatly affects its performance, and the existing asymmetric hysteresis models are either inaccurate or complicated. In this paper, an accurate and simple asymmetric hysteresis model is proposed based on the Prandtl-Ishlinskii (PI) model. Firstly, the Play operator is modified to be asymmetric to enhance its flexibility, and the influence of parameters on the operator is analyzed. Secondly, the Asymmetric Prandtl-Ishlinskii (API) model is proposed based on the asymmetric Play operator and verified by experiment. Compared with several existing models, the API model can describe the asymmetric hysteresis in a more accurate and simple manner under the same conditions. Thirdly, the parameters of the API model are optimized. Compared with the unoptimized API model, the optimized one can reduce the number of parameters and maintain high accuracy. Furthermore, the influence of the order on accuracy is discussed, and a guidance for selection of the order is provided. Last but not least, the optimized API model is used to compensate for the hysteresis. The experimental results show that the compensator based on this model can effectively suppress the hysteresis of the piezoelectric actuator.

Research on Asymmetric Hysteresis Modeling and Compensation of Piezoelectric Actuators with PMPI Model.

Abstract: Because of fast frequency response, high stiffness, and displacement resolution, the piezoelectric actuators (PEAs) are widely used in micro/nano driving field. However, the hysteresis nonlinearity behavior of the PEAs affects seriously the further improvement of manufacturing accuracy. In this paper, we focus on the modeling of asymmetric hysteresis behavior and compensation of PEAs. First, a polynomial-modified Prandtl-Ishlinskii (PMPI) model is proposed for the asymmetric hysteresis behavior. Compared with classical Prandtl-Ishlinskii (PI) model, the PMPI model can be used to describe both symmetric and asymmetric hysteresis. Then, the congruency property of PMPI model is analyzed and verified. Next, based on the PMPI model, the inverse model (I-M) compensator is designed for hysteresis compensation. The stability of the I-M compensator is analyzed. Finally, the simulation and experiment are carried out to verify the accuracy of the PMPI model and the I-M compensator. The results implied that the PMPI model can effectively describe the asymmetric hysteresis, and the I-M compensator can well suppress the hysteresis characteristics of PEAs.

Research on improving the measurement accuracy of the AACMM based on indexing joint

Abstract: In order to improve the measurement accuracy of articulated arm coordinate-measuring machines (AACMMs), a new kind of AACMM based on an indexing joint structure is proposed in this paper. The working principle of the indexing joint is introduced, and a kinematic model of the measuring machine is established based on this principle. The influence weight of the angle error for each joint on the measurement accuracy is analyzed by simulations, and the changes in the accuracy, measurement space and flexibility of the measuring machine before and after adopting the indexing joint are compared. The results show that the use of the indexing joint can effectively improve the measurement accuracy of the AACMM, and the replacement of the first two joints with the indexing joints has the most obvious improvement effect on the measurement accuracy, and has little influence on the measurement space and flexibility. The indexing joint-based AACMM can provide a new idea for the research of improving the measuring accuracy of the AACMM.

Theoretical and Numerical Analysis of Blasting Pressure of Cylindrical Shells under Internal Explosive Loading

Abstract: Cylindrical shells are principal structural elements that are used for many purposes, such as offshore, sub-marine, and airborne structures. The nonlinear mechanics model of internal blast loading was established to predict the dynamic blast pressure of cylindrical shells. However, due to the complexity of the nonlinear mechanical model, the solution process is time-consuming. In this study, the nonlinear mechanics model of internal blast loading is linearized, and the dynamic blast pressure of cylindrical shells is solved. First, a mechanical model of cylindrical shells subjected to internal blast loading is proposed. To simplify the calculation, the internal blast loading is reduced to linearly uniform variations. Second, according to the stress function method, the dynamic blast pressure equation of cylindrical shells subjected to blast loading is derived. Third, the calculated results are compared with those of the finite element method (FEM) under different durations of dynamic pressure pulse. Finally, to reduce the errors, the dynamic blast pressure equation is further optimized. The results demonstrate that the optimized equation is in good agreement with the FEM, and is feasible to linearize the internal blast loading of cylindrical shells.

Novel spherical hinge based on spatial indexing positioning

Abstract: The utility model discloses a novel spherical hinge based on spatial indexing positioning. An existing high-precision spherical hinge is generally complex in structure. The device comprises a hemispherical shell, a ball head, a laser emitter, a ball socket, a photoelectric sensor, a spring and a ball, a blind hole group is formed in the ball head; a spring and a ball are arranged in the blind hole; the ball socket is provided with a spherical hole group; a laser emitter is fixedly arranged on the top surface of the ball socket; the hemispherical shell is fixed on a ball head output rod of theball head; a photoelectric sensor group is arranged on the inner spherical surface of the hemispherical shell; and each spherical hole of the ball socket is embedded with one ball corresponding to theposition of the ball head. According to the utility model, as long as the angle of the spherical hole is calibrated in advance and each photoelectric sensor is numbered, the azimuth angle and the deflection angle of the ball head can be measured, and the high-precision spherical hinge space corner can be obtained by utilizing the photoelectric sensors with low precision and low cost.

Modeling and Compensation for Asymmetrical and Dynamic Hysteresis of Piezoelectric Actuators Using a Dynamic Delay Prandtl-Ishlinskii Model.

Abstract: Piezoelectric actuators are widely used in micro- and nano-manufacturing and precision machining due to their superior performance. However, there are complex hysteresis nonlinear phenomena in piezoelectric actuators. In particular, the inherent hysteresis can be affected by the input frequency, and it sometimes exhibits asymmetrical characteristic. The existing dynamic hysteresis model is inaccurate in describing hysteresis of piezoelectric actuators at high frequency. In this paper, a Dynamic Delay Prandtl–Ishlinskii (DDPI) model is proposed to describe the asymmetrical and dynamic characteristics of piezoelectric actuators. First, the shape of the Delay Play operator is discussed under two delay coefficients. Then, the accuracy of the DDPI model is verified by experiments. Next, to compensate the asymmetrical and dynamic hysteresis, the compensator is designed based on the Inverse Dynamic Delay Prandtl–Ishlinskii (IDDPI) model. The effectiveness of the inverse compensator was verified by experiments. The results show that the DDPI model can accurately describe the asymmetrical and dynamic hysteresis, and the compensator can effectively suppress the hysteresis of the piezoelectric actuator. This research will be beneficial to extend the application of piezoelectric actuators.

Temperature-dependent asymmetric Prandtl-Ishlinskii hysteresis model for piezoelectric actuators

Abstract: Abstract A temperature-dependent asymmetric Prandtl-Ishlinskii (TAPI) model is developed to describe changes in hysteresis curves with respect to temperature found in the displacement curves vs. input voltage of a piezoelectric actuator (PEA). The proposed modeling scheme considers nonlinearities in an idealized capacitor term in the electromechanical model of the PEA to introduce both asymmetry and temperature dependence in the model. The developed model has the advantage of incorporating asymmetric and thermal effects in a hysteresis-free region of the model which simplifies inversion of the model as well as parameter determination. A parameter identification scheme is described to simplify model identification, even for a large number of thresholds, based on the advantages of the classical Prandtl-Ishlinskii model. The TAPI model is verified experimentally and a compensator is designed to demonstrate that the PEA output is effectively linearized throughout the temperature range.

Advanced Trajectory Control for Piezoelectric Actuators Based on Robust Control Combined with Artificial Neural Networks

Abstract: In applications where high precision in micro- and nanopositioning is required, piezoelectric actuators (PEA) are an optimal micromechatronic choice. However, the accuracy of these devices is affected by a natural phenomenon called “hysteresis” that even increases the instability of the system. This anomaly can be counteracted through a material re-shape or by the design of a control strategy. Through this research, a novel control design has been developed; the structure contemplates an artificial neural network (ANN) feedforward to contract the non-linearities and a robust close-loop compensator to reduce the unmodelled dynamics, uncertainties and perturbations. The proposed scheme was embedded in a dSpace control platform with a Thorlabs PEA; the parameters were tuned online through specific metrics. The outcomes were compared with a conventional proportional-integral-derivative (PID) controller in terms of control signal and tracking performance. The experimental gathered results showed that the advanced proposed strategy had a superior accuracy and chattering reduction.

Research on Precision Blanking Process Design of Micro Gear Based on Piezoelectric Actuator.

Abstract: In order to process micro scale parts more conveniently, especially the micro parts with complex shape, a new micro blanking equipment based on piezoelectric ceramic driving is proposed in this paper. Compared with other large precision machining equipment, the equipment cost has been greatly reduced. Using displacement sensor to detect the change of output displacement and feedback control piezoelectric actuator to control the change of relevant parameters, the control precision is high. The micro gear parts with diameter less than 2 mm are obtained through the blanking experiment on the experimental equipment. From the relationship between the obtained time and the punch output force, output displacement and die adjustment, it can be seen that the designed equipment has good processing performance and can complete the blanking forming of micro parts well.

Temperature-dependent asymmetric Prandtl-Ishlinskii hysteresis model for piezoelectric actuators

Abstract: A temperature-dependent asymmetric Prandtl-Ishlinskii (TAPI) model is developed to describe changes in hysteresis curves with respect to temperature found in the displacement curves vs. input voltage of a piezoelectric actuator (PEA). The proposed modeling scheme considers nonlinearities in an idealized capacitor term in the electromechanical model of the PEA to introduce both asymmetry and temperature dependence in the model. The developed model has the advantage of incorporating asymmetric and thermal effects in a hysteresis-free region of the model which simplifies inversion of the model as well as parameter determination. A parameter identification scheme is described to simplify model identification, even for a large number of thresholds, based on the advantages of the classical Prandtl-Ishlinskii model. The TAPI model is verified experimentally and a compensator is designed to demonstrate that the PEA output is effectively linearized throughout the temperature range.