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To realize high performance and suppress the backward motion of the inertia piezoelectric actuator, a novel inertial piezoelectric actuator with double-stator cooperative motion is proposed, designed, fabricated, and tested. The structure and the operation principle of the proposed actuator are first explained in detail. Then the flexible structure is analyzed through the finite element simulation. In addition, the dynamic model of the actuator with double-stator working mode is established and simulated in MATLAB/Simulink, and the step characteristic is investigated, which provided a guidance for the design and optimization of inertial piezoelectric actuators with double-stator. Finally, an experimental investigation of the proposed actuator prototype was carried out and the results showed a significant improvement in the performance of the proposed actuator compared to the previous double-stator inertial piezoelectric actuators. The actuator exhibits a maximum speed of 32.84 mm/s, a maximum lateral load of 20 N, a maximum vertical load of 200 N, a minimum backward rate of 0.91%, and a minimum resolution of 127.5 nm. The actuator with double-stator can improve the maximum output performance to a certain extent, and suppress the backward rate, presenting a specific reference value for the design of future high-performance piezoelectric actuators. [ABSTRACT FROM AUTHOR]

To study the fabrication processes of micro-texture for the elliptical vibration assisted turning technique and the characteristics of machined micro-surfaces, the change rules of surface microtexture was analyzed with vibration principle of ellipse and the micro-texture formation under different speeds and feed rates. The vibration track, surface topography, single micro-texture geometry size and surface roughness were analyzed under the elliptic vibration track measurement tests and eliptic vibration turning tests. The analyses results show that in the turning test processes, compared to the common turning, due to the space elliptic movement of the tool, the surface of ultrasonic elliptical vibration turning presents micro-texture grooves similar to ellipse. With the changes of rotation speed and feed rate, it indicates that the geometric size, profile height and surface roughness of micro-texture grooves will change regularly based on the theoretical analyses and experimental results. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the problems of system detuning, amplitude attenuation, and even vibration stop after the load was applied to the acoustic system during ultrasonic-assisted vibration processing. In the theoretical part, the overall theoretical model of the ultrasonic longitudinal–torsional composite drilling system (ULTCDS), including the longitudinal–torsional composite horn, transducer, and load was established based on the four-terminal network, combined with the longitudinal and torsional vibration equations of the variable cross-section rod. Also, the influence of the load on the input impedance and output amplitude of the acoustic system was preliminarily analyzed. In the simulation part, the static and dynamic drilling force was simulated by the pre-stressed modal and transient dynamic analyses, and the influence of the force load on the resonant frequency and output amplitude of the system was further explored. In the experiment part, the static force loading test and the ultrasonic drilling test of titanium alloy were designed. The micro-morphology of drilling holes under different processing parameters was observed, and the influence of force load on the system characteristics and stability was explored. The results showed that when the system was subjected to a force load greater than 400 N, the system current and frequency were greatly offset, the electromechanical conversion efficiency reduced, and the amplitude was attenuated to below the amplitude at empty load. In the ultrasonic-assisted drilling of titanium alloy processing, the acoustic system undergoes an obvious detuning phenomenon and the drilling quality is attenuated when the current increased by more than 60% and the frequency changed by more than 350 Hz, affecting the stability of the system and the ultrasonic-assisted processing effect. [ABSTRACT FROM AUTHOR]