Force Amplification Mechanism for Increased Stroke and Speed Responses of Piezoelectric Stick-Slip Miniaturized Linear Motor

Piezoelectric stick-slip miniaturized linear-motor (PZT-SS-MLM) based on mechanical advantage mechanism design exhibits amplified displacement response and enhanced motor speed compared to conventional designs [1-4]. Due to the physics of mechanical advantage, the displacement amplification results definitely with specific force attenuation, which limits the load actuation-capacity. Therefore, critical design challenges will be encountered when large force actuation and miniaturized motor scale are required, such in medical implantable motors.

In this work, the Force-Amplification-Mode (FAM) configuration of mechanical advantage was investigated as alternative design approach for the conventional Displacement-Amplification-Mode (DAM) PZT-SS-MLM. In stick-slip motor, the total-displacement actuation consists of two components. One results from expansion deformation of mechanical advantage mechanism, after deformation of the PZT element. Another component is an extended
displacement results due to the gained acceleration of slipping mass, after the mechanical expansion of mechanical advantage mechanism, or in other words, after releasing of elastic energy stored in mechanical advantage mechanism, to a kinetic energy of the moving slipping mass. The larger the stored elastic energy, the larger the transferred kinetic energy. Therefore, the aim of comparison study in this work was to analyse the effect of applying larger actuation force, thus larger acceleration on the displacement, speed and load force limitation of the actuated object.

In this work, a mechanical system model based on Simulink software was developed for a proposed design of stick-slip motor. Only the orientation of a cubic PZT element identifies the mode configuration of the motor. The preliminary results showed that FAM exhibited roughly five times more speed, at hundred times more loading force, compared to DAM. Interestingly, when the output displacement was compared to maximum expansion of mechanical advantage mechanism, then FAM showed larger response compared to DAM. Therefore, FAM might be key design approach for further improved PZT-SS-MLM compared to conventional DAM ones.

Literature
[1] M. Hunstig; Piezoelectric Inertia Motors – Acritical Review of History, Concepts, Design, Applications, and Perspectives, Actuators 2017, 6(1), 7; 2017.
[2] A. Guignabart, A. Pages, O. Freychet, F. Barillot, J. Stentz, C. Belly, T. Maillard, F. Claeyssen; Improvement of MSPA: Module of Stepping Piezo Actuator; Actuator 2018; Bremen, Germany, 25-27 June 2018.
[3] W. Huang, M. Sun; Design, Analysis, and Experiment on a Novel Stick-Slip Piezoelectric Actuator with a Lever Mechanism; Micromachines 2019, 10, 863; 2019.
[4] X. Lu, Q. Gao, Y. Li, Y. Yu, X. Zhang, G. Qiao, T. Cheng; A Linear Piezoelectric Stick-Slip Actuator via Triangular Displacement Amplification Mechanism; IEEEAccess; vol. 8, 2020.