Inchworm rotary piezoelectric actuators (PAs) have been widely utilized in the ultraprecision rotary positioning mechanisms because of their high precision and theoretical no backward motions. Existing inchworm rotary PAs are still bothered with the complicated structures driven by at least three piezoelectric stacks (PSAs) and relatively low speed. In this article, inspired by the finger structure, we present a simplified inchworm rotary PA driven by only two PSAs. The human finger twist motion is first imitated and utilized to increase the rotation from one to four times in one cycle, which improves the output speed and no backward motion can be observed in the rotation curves. Under a voltage of 150 V and a frequency of 20 Hz, the actuator achieved a maximum rotation speed of 0.16 rad/s, a carrying load of 0.5 kg and an output torque of 0.05 N·m. Furthermore, this actuator achieved a high step repeatability in the large scale of 360°, whose maximum deviation is less than 0.8 mrad.

Robotic micromanipulation technology plays a fundamental supporting role in biomedical engineering field. However, it is still a challenge for robotic manipulators to meet the puncture performance requirements for complex cells and curved capillaries with different sizes, because they are difficult to achieve a comprehensive characteristic of multi-DOF, long stroke, high displacement resolution, large puncture force, and high force resolution for limitations of structures, driving elements, and actuation methods. To addresses this challenge, this work proposes the conceptual design of a piezoelectric robotic manipulator driven by a single piezoelectric actuator. A configuration design idea and a new actuation method are elaborated to achieve 2-DOF cross-scale manipulation and adjustable puncture force. Theoretical analyses and simulations are carried out to investigate the influence of key structural parameters on displacement response and puncture force, as well as to determine the parameters. A prototype is fabricated, a dedicated handheld controller is developed, and a robotic micropuncture system is constructed to conduct characteristic testing and application research. Experimental results reveal that the manipulator achieves linear and rotary strokes of 38.5 mm and 360°, displacement resolutions of 48 nm and 0.38 μrad, a puncture force range from 1.70 mN to 301.34 mN, and a force resolution of 0.13 mN. Additionally, the manipulator successfully performs delicate puncture of silicone capillaries with different sizes and a curved silicone capillary under collaborative manipulation of the piezoelectric platform. This work exhibits a high-performance piezoelectric robotic manipulator and verifies its feasibility in micropuncture of tiny and complex-shaped organisms.

Inertial positioning platforms driven by piezoelectric actuators have been employed in many precision applications. However, challenges including unstable pose keeping and intractable displacement backward still exist. In this study, a locking device is designed and embedded in a piezoelectric inertial rotary platform to achieve the functions of power- off locking and 2-degree of freedom (DOF) backward motion suppression. The vertical output displacement of the locking end is converted from the horizontal elongation of the lead zirconate titanate (PZT) stack by the flexible hinge mechanisms of the locking device, which is used to lock the rotor of the rotary platform. Theoretical and simulation analyses of the locking mechanism are performed and its dominant parameters are optimized. A prototype is fabricated and a series of experiments are performed. Compared with the inertial rotary platform without the locking device, the locking ability is increased by 4.55 times and the backward ratio is reduced from over 60% to below 12%. The application of locking device not only improves the pose keeping ability of the inertial positioning platform, but also improves its displacement output characteristics through backward motion suppression.