A Driving-Clamping Integrated Inchworm Linear Piezoelectric Actuator With Miniaturization and High Thrust Density

This article presents an inchworm linear piezoelectric actuator (ILPA) to address the prevalent issues of bulk and complexity in existing ILPAs. It has the characteristics of miniaturization with a size of 44 × 13 × 24 mm³ and a weight of 36.0 g. It integrates multiple functions within a compact form factor. The mechanical structure is simplified to a stator and an output shaft. The integrally machined stator is used as a guide unit without additional guideways and components. A key feature of the ILPA is its integrated driving mechanism that combines driving and clamping actions. This mechanism is designed as a bridge-type displacement amplifier, where the main displacement serves the driving function, while the parasitic displacement provides the clamping action. Experimental results show that the ILPA achieves a maximum speed of 1691.8 µm/s under the condition of square wave excitation with a frequency of 417 Hz and an input voltage of 120 V. Furthermore, it delivers a thrust of 1.5 N and a self-locking force of 2.1 N. Its force-to-volume ratio with a thrust density of 1.09 × 10⁻⁴ N/mm³ stands out. It has been successfully employed in several practical applications, including detecting chips and microscopic observation tasks.