Zhu Pancheng, Peng Hanmin, Zhao Gai, Chen Ni
State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
Rev Sci Instrum. 2021 May 1;92(5):055002. doi: 10.1063/5.0045215.
Friction materials form a critical component of piezoelectric actuators, and wear of the material affects output and service life of the actuator. This paper examines the influence of polyimide (PI) composites when used as a friction material on the performance of a legged piezoelectric bending actuator. We design and manufacture demountable shoe soles, made of a novel PI-based friction material, for an actuator. A Coulomb friction model is also established to determine the behavior resulting from contact-induced friction between the surface and the actuator. Reciprocating wear tests involving an insulation rubber pad against phosphor bronze and PI composites as friction materials yielded average friction coefficients of 0.21 and 0.28, respectively. We also found that PI composites have higher wear resistance than phosphor bronze, with a specific wear rate of 1.36 × 10 mm/N m. The results of experiments and simulations indicate that the shoe soles made of PI composites reduced the actuator's driving frequency and vibrational amplitude, but they did not affect the principle of locomotion of the actuator. Furthermore, the operational stability of the actuator improved by 46.8% by using the demountable shoe soles made of PI composites, albeit at the cost of its velocity and load capacity. This work has guiding significance for the design and selection of friction materials for piezoelectric actuators.
摩擦材料是压电致动器的关键组成部分，材料的磨损会影响致动器的输出和使用寿命。本文研究了聚酰亚胺（PI）复合材料作为摩擦材料时对腿部压电弯曲致动器性能的影响。我们为致动器设计并制造了由新型PI基摩擦材料制成的可拆卸鞋底。还建立了库仑摩擦模型，以确定表面与致动器之间接触引起的摩擦所导致的行为。以绝缘橡胶垫与磷青铜和PI复合材料作为摩擦材料进行的往复磨损试验，其平均摩擦系数分别为0.21和0.28。我们还发现，PI复合材料比磷青铜具有更高的耐磨性，比磨损率为1.36×10⁻⁶mm²/N·m。实验和模拟结果表明，由PI复合材料制成的鞋底降低了致动器的驱动频率和振动幅度，但不影响致动器的运动原理。此外，使用由PI复合材料制成的可拆卸鞋底，致动器的运行稳定性提高了46.8%，尽管其速度和负载能力有所下降。这项工作对压电致动器摩擦材料的设计和选择具有指导意义。
