Development of a deflector-jet electrohydraulic servovalve using a giant magnetostrictive material

Giant magnetostrictive actuators (GMAs) have received considerable attention in recent years and are becoming increasingly important in the exploitation of a new type electrohydraulic servovalve. In this paper, a deflector-jet servovalve (DJSV) using a giant magnetostrictive material (GMM) is developed for the first time, and the servovalve is mechanically less complex than a conventional DJSV. Next, a mathematical model of the GMM-based DJSV is built, which involves five submodels: a dynamic model of the power amplifier; a dynamic magnetization model of the GMM rod; a magnetoelastic model of the GMM rod; a kinetic model of the GMA; and a deflector-jet amplifier model. The experimental platform used for measuring the performance of the GMM-based DJSV is established, the prototype valve is fabricated, and the related unknown parameters are identified by experimental data from the GMA. Finally, a simulation and experimental research are performed on the GMM-based DJSV; the results indicate that the present GMM-based DJSV has a large output-pressure range, a rapid response, and a high bandwidth, which provides a competitive way to develop a new type of high-frequency and high-flow-rate electrohydraulic servovalve. Additionally, the measured characteristics of the prototype valve are in good agreement with the predicted results and demonstrate that the operational concept is viable, and the present mathematical model is reliable.