Research on mathematical modeling of the servo valve torque motor considering the variation of working air-gaps leakage flux

Abstract

In the current research of the magnetic circuit model of the servo valve torque motor, the magnetic flux leaking from working air-gaps is regarded as constant. However, the working air-gaps leakage flux varies with the armature rotation angle, which affects the accuracy of the existing mathematical model of the torque motor. To solve this problem, a new mathematical model of the torque motor with two working air-gaps is built. First, different from the previous model, the variation of the working air-gaps leakage flux is considered in the magnetic circuit model. A more detailed mathematical model of the torque motor is established based on the magnetic circuit model. Second, the finite element method is used to reveal that there is a linear relationship between working air-gaps leakage flux and armature rotation angle in a certain range of rotation angles. Then, the new model is validated by numerical calculation, which indicates that the theoretical results calculated by this new model show better agreement with the simulation results compared to the previous model when the armature rotation angle increases. Further, the theoretical results of the electromagnetic torque constant and magnetic spring stiffness acquired by the new model and the previous model are compared. The comparison shows that the variation of the working air-gaps leakage flux has the greatest influence on the magnetic spring stiffness. Finally, the experiments on the torque motor are conducted to verify the accuracy of the new model. The theoretical results obtained by this new model are better consistent with the experimental results than that obtained by the previous model. This study shows that considering the variation of working air-gaps leakage flux is valuable to improve the accuracy of the magnetic circuit model of the torque motor, which provides an effective guidance for the structural optimization and performance prediction of the torque motor.

The modeling and analysis of operating characteristics and temperature drift of deflector jet servo valve under the wide temperature range

“…Serving as the primary stage energy conversion device within the DJSV, the conversion process significantly affects, and in some cases, determines the overall performance of the entire servo system. [7][8][9] Torque motors were initially invented in the 19th century. Siemens developed a dual-input valve.…”

“…Serving as the primary stage energy conversion device within the DJSV, the conversion process significantly affects, and in some cases, determines the overall performance of the entire servo system. 7–9…”

“…Liu established a comprehensive mathematical model of torque motors considering the working air gap magnetic leakage. 8 Since torque motors function as devices for electro-mechanical conversion, it is crucial to explore their static and dynamic characteristics. Anderson et al adopted a simplified linear model to characterize the torque motors’ dynamic characteristics.…”

Modelling and characteristics analysis of an electro-hydraulic proportional valve with a discrete pilot stage for underwater hydraulic manipulators

“…7 The underwater hydraulic manipulator has a large power-weight ratio and high dynamic performance, making it suitable for complex underwater operational tasks. 8 Considered as the core element of the underwater hydraulic manipulator, a two-stage electro-hydraulic proportional valve (EHSV) is used to convert an elector-hydraulic signal and amplify the power of the manipulator, 9,10 which directly determines its control accuracy and dynamic performance. For a traditional two-stage EHSV, a 3/4-way spool is usually selected as the pilot stage, and it realises bidirectional movement of the EHSV by controlling the pressure in the two chambers.…”