Angular displacement modeling and excitation signal optimization for a stepping giant magnetostrictive rotary...

Giant magnetostrictive rotary actuators (GMRAs) can realize rotary motion in large scale and with high precision. A series of rectangular voltage signals organized in strict order exerted on GMRA helps its clamping mechanism and driving mechanism complete specific actions such as clamping, loosening, and actuating, thus leading to the stepping output of the rotor. In order to describe the overall performance of GMRA, an angular displacement model is established, which can be divided into four parts, namely, the current model, magnetic field model, output force model, and vibration model. The experimental results indicate that the established model agrees well with the actual performance of GMRA in operating conditions. After that, utilizing the established model, simulations are conducted to analyze the angular response of GMRA. According to the simulation results, the order of driving signals is optimized, making the maximum driving frequency rise from 160 Hz to 210 Hz, while the peak angular speed of GMRA reaches 70.77 mrad/s. The modeling and optimization methods proposed in this paper can be helpful for the structural optimization and controller design of GMRA as well.