Fundamental Theory And Experiment Study Of Giant Magnetostrive Self-Sensing Actuator

The giant magnetostrictive material (GMM) possesses large magnetostriction, fast response etc. It is a new functional material which has bi-directional transduction effects. Actuators work using the Magnetostrictive effect, while sensors work using magnetostrictive converse effect. GMM not only has magnetostrictive effect but also has magnetostrictive converse effect, so it can be used as self-sensing actuator. GMM is applied to self-sensing actuator, it has the function of sensor and actuator simultaneously, and has some advantage in decreasing system volume and weight, saving space, true collocation and increasing stability.Firstly, GMM and its application are introduced, the concept of self-sensing is summarized, the significance of giant magnetostrictive self-sensing is analyzed.Subsequently, the structure and the principle of giant magnetostrictive actuator (GMA) are studied. The static behavior and dynamic behavior are analyzed. According to the result of the experiment, the fundamental character is validated. It also provides the foundation for how to choose the bias current and AC current. The output strain of GMA in different frequent is compared. It provides theory and experiment datas to the bridge circuit.Acording to the bilateral electromechanical transducer effects the theory of self-sensing is analyzed, and the simulation models of the two methods of self-sensing actuator are built up.The Jiles-Atherton (J-A) non-linear model is used to bridge circuit and compiled M-file S-functions. Then apply it to simulation. The phase error which is caused by integral between displacement and the speed can be eliminated. So the simulation is in good agreement with the actual model. The small signal of bridge circuit is magnified and filtered in simulation. The influence of clutter signal and nonlinear can be reduced. So it can provided the the foundation to the actual amplifier and filter.In the experiment of bridge circuit, the waves of voltage and strain is measured, the datas of the experiment are dealed with according to the curve fitting tool in Matlab. The equations of waves are got, and the parameters in bridge circuit are calculated. The actual amplifier and filter are designed.Pickup coils which are used to measure the magnetic induction intensity in the observer have been considered. This method which is suitable for the alternating magnetic field is based on Faraday electromagnetic induction principle. The observation operation is carried on in Matlab, and data fitting is made to the result which measured by strain gauge, so as to validate the sensation signal through the comparison of experimental result with the observation operation result. .