An Auxiliary Friction Method for Miniaturizing the Inertial Impact Piezoelectric Actuators

The inertial impact piezoelectric actuators (IIPAs) are promising to be miniaturized as microactuators due to their simple structure and high positioning resolution. In this article, a novel method is proposed to reduce the dependence on the inertial mass by exerting auxiliary friction on the inertial mass. To verify the validity of the method, a traditional IIPA (TIIPA) and an auxiliary friction IIPA (AFIIPA) are designed. The static analysis is conducted to determine their structural parameters. Then, their size and weight are identified as 9.6 mm × 10 mm × 7 mm and 0.8 g (the lightest IIPA to our knowledge), respectively. The dynamic analysis and experiments are performed, and the results demonstrate that, under the same experimental conditions, the AFIIPA has lower sensitivity to inertial mass reduction and better output performances than those of the TIIPA. The maximum speed, output force, and resolution of the AFIIPA are improved by 81.8%, 67.2%, and 30.9%, respectively, compared with the TIIPA. Besides, the AFIIPA has balanced comprehensive performances with extremely lightweight compared with some previous microactuators. This study provides a new miniaturization method for the IIPAs, which could advance the further development and applications of the micro-IIPAs.