Analysis of Interactions Between Frictional Contact and Operating Conditions in Piezoelectric Stick-Slip Actuator

The performance of piezoelectric-based stick-slip actuators is intricately influenced by the interplay between key design and operating parameters such as the electrical driving signal, mechanical architecture, inertia, and frictional contact. Fostering an interdisciplinary approach towards a holistic understanding of their dynamic behavior is crucial to maximise an actuator's performance. Therefore, considering the significant role of friction, this research investigates its effect and interaction with the operating frequency on the actuator's performance, using dynamic finite element analysis as a proof of concept. The analysis is supported by experimental verification using various material couplings in an actuator prototype. The study reveals that at low operating frequencies, actuator with a low-friction interface achieve greater displacements compared to those with higher friction. Interestingly, at elevated frequencies, the displacements become comparable across interfaces with different friction coefficients. The findings suggest that both load capacity and displacement can be enhanced by selecting material pairs with higher friction coefficients at higher frequencies, while those with lower friction coefficients would be more promising for precise positioning, with low initiation frequencies. Therefore, this research introduces a novel approach for optimizing actuator performance by tuning contact dynamics across the operating frequency spectrum, offering insights into the design and development of piezoelectric-based stick-slip actuators.