A multilayer piezoelectric actuator, with dimension of 10 mm×10 mm×60 mm, which can output a tensile displacement directly by exploring the d31 effect of piezoelectrics, was fabricated using soft Lead Zircon...A multilayer piezoelectric actuator, with dimension of 10 mm×10 mm×60 mm, which can output a tensile displacement directly by exploring the d31 effect of piezoelectrics, was fabricated using soft Lead Zirconate Titanate(PZT) ceramics. The performance of the actuator was characterized by a special home-made experimental setup under electric fields varying from 200 to 1 000 V/mm with the preload varying from-150 to 100 N at room temperature. Results showed that it can output a maximum tensile displacement of 12 μm under unipolar electric field of 1 000 V/mm and preload was independent with generative displacement in the range of testing preload. Additionally, using the actuator, we built a micro loading apparatus, which can be used to test the fracture behavior of brittle materials.展开更多
This article, in order to precisely impose friction on aircraft and weapon actuation systems, presents a new friction loading method characteristic of ＂torque-zero velocity＂ switching control with an electro-hydraul...This article, in order to precisely impose friction on aircraft and weapon actuation systems, presents a new friction loading method characteristic of ＂torque-zero velocity＂ switching control with an electro-hydraulic load simulator. As the general Stribeck friction model has little related to static friction, it proposes a ＂torque-zero velocity＂ switcher, in which a zero-velocity controller is developed to load the static friction and a torque controller the kinetic friction. With the help of mathematical modeling, this article designs a ＂torque-zero velocity＂ switching controller and, correspondingly, provides a ＂dual-threshold judgment＂ algorithm. Simulation results indicate that the proposed method can be successfully used to carry out the static and kinetic friction simulation with an electro-hydraulic load simulator.展开更多
基金Supported by the National Natural Science Foundation of China(11402177)the Research Foundation of Wuhan University
文摘A multilayer piezoelectric actuator, with dimension of 10 mm×10 mm×60 mm, which can output a tensile displacement directly by exploring the d31 effect of piezoelectrics, was fabricated using soft Lead Zirconate Titanate(PZT) ceramics. The performance of the actuator was characterized by a special home-made experimental setup under electric fields varying from 200 to 1 000 V/mm with the preload varying from-150 to 100 N at room temperature. Results showed that it can output a maximum tensile displacement of 12 μm under unipolar electric field of 1 000 V/mm and preload was independent with generative displacement in the range of testing preload. Additionally, using the actuator, we built a micro loading apparatus, which can be used to test the fracture behavior of brittle materials.
基金National Natural Science Foundation of China （50825502）
文摘This article, in order to precisely impose friction on aircraft and weapon actuation systems, presents a new friction loading method characteristic of ＂torque-zero velocity＂ switching control with an electro-hydraulic load simulator. As the general Stribeck friction model has little related to static friction, it proposes a ＂torque-zero velocity＂ switcher, in which a zero-velocity controller is developed to load the static friction and a torque controller the kinetic friction. With the help of mathematical modeling, this article designs a ＂torque-zero velocity＂ switching controller and, correspondingly, provides a ＂dual-threshold judgment＂ algorithm. Simulation results indicate that the proposed method can be successfully used to carry out the static and kinetic friction simulation with an electro-hydraulic load simulator.
