A microscopic contact model for annular traveling wave ultrasonic motors (ATWUMs) is proposed in this paper, aiming to deeply investigate the dynamic contact behavior between the stator and rotor as well as their friction-driven mechanisms. Compared with traditional contact models of annular traveling wave ultrasonic motors, the LuGre’s microscopic dynamic friction theory is introduced into this model, and the influence of the stator tooth structure is fully taken into account. Additionally, estimation methods for key parameters in the contact model are provided. Based on this model, systematic analysis and evaluation of the normal stress, tangential stress, and mechanical output characteristics within the motor are conducted. Subsequently, the torque-speed characteristics of the prototype are measured through experiments and compared with the simulation results. Experimental results show that the simulated values are highly consistent with the measured ones, thereby validating the effectiveness of the proposed microscopic contact model. To further evaluate the model performance, a comparative analysis between this model and traditional contact models that use Coulomb’s law of friction while neglecting the influence of stator teeth (assuming continuous tooth surfaces) is performed. The comparison results indicate that the proposed model is recognized as superior to traditional models in terms of accuracy.

Crawler-type robots offer unique advantages for extraterrestrial exploration. However, existing planetary rovers of this type face challenges such as complex structures, low energy efficiency, considerable weight, and inadequate adaptability to extreme environments. In contrast, piezoelectric actuation offers notable advantages including compact design, light weight, fast response, and immunity to electromagnetic interference, thereby providing a novel approach for the development of crawler-type exploration robots. This study proposed a crawler-type piezoelectric-actuated robot for extraterrestrial surface exploration, synergistically integrating the advantages of crawler mechanisms and piezoelectric actuation technology. The proposed robot comprised modular ring-beam piezoelectric actuator and crawler belts, utilizing inverse piezoelectric effects to generate traveling waves on the rings for direct frictional drive of the crawler movement. At first, an electromechanical coupling dynamic model of the piezoelectric actuator (featuring a triple-ring dual-beam semi-enclosed configuration) was established via the transfer matrix method to elucidate the actuator's dynamic characteristics and predict its operational performance. Then, a prototype was assembled and experimental characterization of its vibration properties validated the accuracy and effectiveness of the theoretical model through comparative analysis with numerical predictions. Finally, systematic experimental investigations on the prototype's locomotion performance and mechanical output characteristics revealed that under 360 Vp-p excitation voltage, the robot achieved a maximum no-load speed of 23.81 mm/s and could carry a 500 g payload. The results demonstrate that the proposed crawler-type piezoelectric actuator meets the anticipated motion velocity and load capacity, indicating significant potential as a driving system for extraterrestrial exploration. This investigation on the proposed robot demonstrated its promising potential for future extraterrestrial mobile exploration robots in surface reconnaissance and sampling missions on celestial bodies.

Conventional multi-degree-of-freedom (multi-DOF) piezoelectric actuators realize 3D motion by coordinating several orthogonal physical axes (e.g., X/Y/Z). This reliance substantially inflates hardware and control complexity. Therefore, we propose a modal-synergistic and mode-shape spatial position control driving strategy for the stators. By coordinating two distinct vibration modes within two stators, a virtual rotation axis of the spherical rotor is created. Through spatial position control method of the two mode shapes, the driving feet acquire programmable trajectories that reposition the virtual axes in space, thereby enabling controllable multi-directional rotation of the rotor. Building on this concept, the paper first details the configuration of the multi-DOF rotary piezoelectric actuator, the selection and pairing principles of the stator vibration modes, and the rotation mechanism of the rotor under modal synergy. Next, finite-element analyses verify the principle of mode-shape spatial position control, and parameter optimization determines geometric dimensions that make the target vibration modes of the two stators co-resonant. Finally, a proof-of-concept prototype is fabricated and assembled. The prototype achieved stable rotation about eight virtual axes, with a maximum rotational speed of 97.12 deg/s, a speed of 10.62 deg/s under a load torque of 6 mN m, a minimum angular displacement resolution of 59 µrad, and a minimum start-up time of 19.65 ms. Theoretical and experimental results show that the proposed modal-synergy and mode-shape spatial position control method simplifies the actuator structure and drive control and offers a practical route to expanding the motion dimensionality of rotary piezoelectric actuators.

In deep-sea exploration, compact robotic systems encounter considerable difficulties in sustaining effective propulsion under tremendous hydrostatic pressure exceeding 100 MPa. Conventional electric drive systems suffer significant energy losses due to the requirement for large pressure-resistant enclosures, whereas current actuators utilizing functional materials frequently display constraints such as low thrust-to-weight ratios, elevated drive voltages, or insufficient pressure resistance. This work produced a unique seal-free small bionic underwater robot (SBUR) powered by piezoelectric actuation, inspired by anguilliform locomotion. A dual-SBUR system was employed to enhance the design of an underwater mobile platform (UMP), facilitating combined forward propulsion and steering capabilities. First, the structure and design of the SBUR and UMP are elucidated. Subsequently, modal features in air were examined by the transfer matrix method (TMM), while hydrodynamic responses in water were explored utilizing computational fluid dynamics (CFD) simulations. Performance evaluations conducted under standard pressure settings revealed a consistent SBUR forward speed of 152 mm/s. The UMP achieved a forward speed of 43.5 mm/s, generated a thrust of 20 mN, and performed rotations with a minimum radius of 130 mm. Experiments validated the practical feasibility of the SBUR at 110 MPa. The performance decline under elevated hydrostatic pressure did not surpass 3.3%, and it demonstrated negligible temperature sensitivity. Practical validation confirmed the SBUR’s ability to transport payloads of up to 10 kg, highlighting its suitability for deep-sea applications. The proposed robot offers advantages such as miniaturization, low operating voltage, and excellent adaptability to extreme hydrostatic pressure.

The sandwich-type piezoelectric unit group (PUG) constitutes a functional component in piezoelectric transducers, whose dynamic characteristics can be designed and optimized by model-based analysis. However, the conventional transfer matrix method (TMM) faces limitations in modeling a bending-vibration PUG. Specifically, it fails to account for the polarization isolation and the electrode, and lacks the electromechanical transfer conditions for internal elements in the PUG. To overcome these challenges, this paper proposes the electromechanical transfer equation of the sandwich-type PUG. First, the TMM model, characterizing the polarization isolation with dielectric properties, is developed for the piezoelectric ceramic plate (PZT). Then, the electrodes subjected to vibration are retained. The electromechanical transfer conditions are established for the PZT-electrode-PZT situation and the piezoelectric unit (PU)-electrode-PU situation. Subsequently, the bending-vibration transfer equation of the sandwich-type PUG is formulated by combining the bending-vibration PZT model and the electromechanical transfer conditions. Finally, a sandwich-type piezoelectric transducer is employed as a verification case. Numerical results demonstrate that the proposed TMM and finite element method show high consistency in four dimensions: amplitude-frequency characteristics, impedance characteristics, displacement mode shapes, and strain mode shapes. Except for the parallel resonant frequency, all other indicators calculated by the TMM and measured experimentally are in good agreement. This paper proposes a comprehensive modeling methodology for the bending-vibration PUG, facilitating their structural design and optimization.

In dual-stator inertial piezoelectric actuators, the effect of the phase angle of the driving current (PADC) on output performance is poorly understood. In particular, the influence of different phase angles on key performance indicators such as speed, displacement, and load capacity remain unclear. This study introduces a doublestator, single-direction type (SDT) piezoelectric inertial actuator and investigates the effect of varying the PADC on its output characteristics through analytical modeling and experimental validation. A prototype actuator is fabricated, and its performance is evaluated at different PADCs. Experimental results show that increasing the PADC significantly improves the speed, step displacement, load capacity, and drive efficiency. For example, at phi= pi, the step displacement increases by 445.58%, the load capacity increases by 200%, and the efficiency increases by 442% compared to phi= 0. In addition, the step resolution improves by 770% at phi= 0 compared to phi= pi. This work provides new insights into the PADC optimization of SDT double-stator piezoelectric inertial actuators and guidelines for selecting PADC based on application requirements. The results highlight the actuator's potential for high-precision motion control, and future research could focus on optimizing its design and control strategies to further improve its performance and broaden its applicability.

Aiming at the problem that the traditional robot can not grasp multiple types of workpieces by using fixed point teaching method, this paper designs an industrial robot grasping system based on intelligent vision and PLC. The overall scheme of the system is layered according to the IEC62264-1 standard. The visual module and cooperative robot are used as field equipment, PLC is the main controller of the system, HMI and SCADA are used for process monitoring, machine learning technology and a variety of algorithms are adopted, which can quickly and accurately identify the type and color of target workpiece, and realize the multi type workpiece capture of industrial robot and digital control of production unit. The results show that the system has good grasping accuracy, can effectively complete the grasping task of a variety of complex workpieces, effectively improve the production efficiency and quality, and provide strong support for the intelligent upgrading of industrial production.

To enable optical focusing in strong magnetic-field environments, a magnetically compatible piezoelectric optical focusing mechanism (POFM) with dual driving modes has been proposed. The POFM is driven by an inverted Y-shaped piezoelectric stator. By coupling two out-of-plane bending modes, the stator generates elliptical motion at its driving foot. Coarse focusing motion (CFM) is achieved under continuous excitation signals, while fine focusing motion (FFM) is realized under pulsed excitation. The structure of the POFM is designed, and the working principle of the piezoelectric stator is analyzed. Finite element analysis is conducted to optimize the stator’s resonant frequencies of the two bending modes. The prototypes of the piezoelectric stator and the POFM are fabricated for performance evaluation. Experimental results demonstrate that under CFM, the POFM achieves a speed of 37.2 mm/s, a thrust of 6.1 N, and response times of 3.25 ms (startup) and 2.85 ms (stop), enabling coarse focusing. Under FFM, a minimum step resolution of 0.55 $\boldsymbol{\mu}$ m is obtained for fine focusing. The POFM maintains stable output performance under a 1.5 T magnetic field without noticeable magnetic interference. This study offers valuable guidance in the design of piezoelectrically driven optical focusing systems for high-magnetic-field applications.

With the expanding deployment of robots in extreme environments, increasingly stringent performance requirements on joint drive systems. Due to the problems of complex structure, poor environmental adaptability, complex control, and unstable motion in the current robot joint drive methods, which impede their application in extreme environments. To overcome these constraints, this study introduces a novel Piezoelectric-Actuated Robotic Arm (PARA) designed for extreme-environment applications. The PARA utilizes a ring-beam-structured piezoelectric joint actuator, achieving a compact and functionally integrated joint design. This innovative design not only resolves cantilever joint contact warping but also extends the applicability of piezoelectric actuation to cantilever-based robotic systems. An electromechanical coupling dynamic model of the piezoelectric joint actuator was established using the transfer matrix method, which couples piezo-beam dynamics with ring equations in closed form and enables rapid parametric optimisation. Through static simulation analysis, the structural scheme of the PARA can effectively avoid large deformation at the stator and rotor was verified, and its mechanical performance meets mechanical design specifications. Experimental validation was conducted in two phases: Baseline performance testing under standard conditions verified the PARA’s high-precision opening/closing functionality; Extreme-environment testing in high-vacuum and high-temperature settings demonstrated robust operational stability, affirming its suitability for harsh conditions. The experimental results show that the PARA prototype can effectively achieve high-precision opening and closing functions, and has good environmental adaptability. This study lays the technical foundation for the construction of piezoelectric driven robots for extreme environmental operations in the future.

Bolted connections are widely employed in clamps and flanges for vibration control in aerospace and marine systems. However, the imperfect interfaces of bolted connections hinder accurate dynamic evaluation and degrade computational efficiency. To overcome these limitations, a novel frictional contact correction transfer matrix method is proposed. Unlike the traditional transfer matrix method (TMM), which assumes a perfectly rigid connection, this model incorporates a frictional contact correction that iteratively accounts for the relationship between the shear forces of the bolted connection components. In addition, the generalized transfer matrix of elastic beam elements with arbitrary input/output locations is derived, enabling modular assembly of complex connection structures. To validate the proposed method, three bolted connection vibration systems are constructed and finite element simulations with improved friction contact correction are conducted. In addition, three bolted vibration systems were experimentally investigated, and the results of other TMM variants were compared with those of the proposed method. The results demonstrate that the proposed method achieves computational efficiency over 100 times greater than finite element simulations, with accuracy comparable to finite element simulations for the first mode. For the second mode, prediction error increases significantly. Specifically, the method significantly improves computational accuracy compared to other TMM variants, albeit with modestly increased computational cost relative to the other TMM variants. The method provides a concise modeling framework with high computational efficiency, serving as an effective theoretical tool for vibration control and identification within its validated scope.

This article presents an orthogonally configured, series-connected piezoelectric bimorph actuator, aiming to develop a full-ocean-depth biomimetic underwater robot which employs undulatory propulsion and is characterized by a compact form factor, superior maneuverability, and robust compression-resistant performance. First, finite element analysis was performed to systematically investigate the dry/wet modal characteristics and fluid-structure interaction mechanisms of the actuator design. Then, vibration measurement experiments validated the simulation results, confirming a strong correlation between thrust output and the peak height difference of in-phase vibrations, which is further amplified by underwater high-frequency resonance. The integrated wave-propelled robot prototype, equipped with onboard control and power supply units, demonstrated advanced three-dimensional locomotion capabilities in both laboratory tank and outdoor pool environments. Specifically, the robot achieved horizontal and vertical velocities of 54.7 and 12.2 mm/s, and a maximum thrust of 26 mN. Notably, the proposed actuator exhibits a performance degradation of less than 10.8% at 110 MPa and maintains excellent temperature stability. This article presents a novel actuation solution characterized by high power density and low complexity, which holds significant potential for full-ocean-depth exploration applications.

The Langevin transducer, configured with numerous piezoelectric ceramics (PZTs) and electrodes, exhibits a high-power density and can be designed and optimized through dynamic modeling. However, existing modeling approaches face a significant computational challenge, as the dimension of the system matrix increases rapidly with the number of PZTs and electrodes. To address this issue, an improved transfer matrix method (TMM) model is proposed in this paper. First, the transfer equation of the piezoelectric stack (PS), which acts as the vibration excitation source in the Langevin transducer, is derived based on the electromechanical transfer condition. A ternary operation is introduced to combine PZTs and electrodes, resulting in a 3 × 3 matrix. Subsequently, by eliminating the state vectors of internal elements such as the PS, the transfer equation of the entire Langevin transducer is obtained, and its overall transfer matrix retains a dimension of 3 × 3. A Langevin transducer with 12 PZTs and 13 electrodes is used for validation. The resonant frequencies obtained by the proposed TMM, the finite element method (FEM), and experiment are 32,190 Hz, 31,628 Hz, and 30,824 Hz, respectively. The relative error between the TMM and FEM results is 1.78%, showing good agreement. The error compared with experimental results is 4.43%, demonstrating practical applicability. Besides, compared with the conventional TMM, the proposed TMM reduces both the dimension and the condition number of the system matrix while improving computational accuracy, making it an efficient and practical modeling tool.

Conventional electromagnetic and hydraulic release mechanisms involve inherent trade-offs among sealing efficiency, fatigue life, response time, and system complexity. These limitations intensify with water depth. To address this, a single-mode piezoelectric-driven release mechanism (PDRM) is proposed. Its core unit is a contact-coupled piezoelectric actuator (CCPA) excited by a single-phase signal, in which the longitudinal and transverse vibration modes are naturally coupled to generate an elliptical trajectory under eccentric reaction forces. To guide the design of the CCPA, a dynamic model incorporating the clamping structure is developed. This model characterizes vibration behavior under free and clamped boundary conditions and analyzes the influence of structural asymmetry. Key dimensional parameters are optimized using this model, and experiments confirm its high accuracy in predicting frequency and amplitude. Underwater tests on the CCPA prototype demonstrate a maximum driving speed of 0.72 m/s, a thrust of 14 N, and start/stop times of 18 ms and 11 ms. The prototype operates normally at 114 MPa, with a driving speed of 0.44 m/s. The PDRM prototype achieves a release load of 55 kg, with the CCPA speed reaching 0.15 m/s. Environmental tests, including 24-hour dwell at 110 MPa, salt spray, and direct load release, confirm deep-sea reliability. This study presents a piezoelectric actuation concept for release mechanisms that functions under static high hydrostatic pressure, offering a potential alternative to conventional designs.

Joint piezoelectric actuators are widely used in joint drive systems such as robots due to their high precision, self-locking upon power loss, and compact structure. However, conventional standing-wave joint piezoelectric actuators often suffer from unstable driving performance and an inability to achieve bidirectional motion. Traveling-wave types, meanwhile, typically rely on auxiliary components that hinder miniaturization and system integration. To address these challenges, a novel ring-beam structure traveling-wave driven joint piezoelectric actuator is proposed. Firstly, the operating principle was revealed through theoretical modeling and validated using finite element analysis, which also facilitated the determination of optimal stator dimensions. Subsequently, the vibration characteristics of the stator are tested to identify its optimal operating frequency. Finally, the performance of the actuator is evaluated. Performance tests demonstrated that, under an excitation voltage of 300 Vp-p at 33.75 kHz, the actuator achieved a maximum rotational speed of 117 rpm and a stall torque of 7.15 mN m with a resolution of 28.89 '' in the forward direction; the corresponding values in reverse were 104 rpm, 7.13 mN m, and 16.39 ''. These results confirm the correctness of the proposed design and its driving principle, providing a new approach for the miniaturization and integration of joint piezoelectric actuators.

Multi-degree-of-freedom (M-DOF) actuation technology has garnered extensive research and applications in precision positioning, optical alignment, and biomedical manipulation due to its salient advantages of flexible motion, high integration, and reliability. Advancements in novel materials have facilitated the development of M-DOF actuators based on diverse driving principles. Compared with other actuation mechanisms, M-DOF piezoelectric actuators have become a critical solution for performance enhancement and holistic optimization of precision actuation systems. Their compact structure, rapid response, high precision, low-speed high-torque capability, and electromagnetic interference-free operation have attracted significant attention. This paper provides a comprehensive review of research progress in M-DOF piezoelectric actuators over the past three decades. First, current challenges and development trends in M-DOF actuation technology are outlined, with comparative analysis highlighting the unique advantages of piezoelectric actuators. Next, a systematic classification of M-DOF piezoelectric actuators is presented alongside their primary application domains. Finally, challenges are analyzed through five key design aspects, and future research directions are prospected. This review aims to establish a foundational reference for advancing research and applications in M-DOF piezoelectric actuators.

Piezoelectric vibration feeders (PVFs) are widely used in industry for material conveyance. Accurate and efficient dynamic models are critical for precise and rapid structural design, as well as for stable and high-speed material transport. However, most existing theoretical models idealize the key components of vibration feeders as rigid bodies, thereby neglecting their inherent flexibility. In addition, comprehensive dynamic models of PVFs that incorporate electromechanical coupling remain scarce. Moreover, the common assumption of rigid bolt connections introduces additional inaccuracies in the predicted dynamic response. To address these issues, an electromechanical coupling dynamic model for a bolted PVF with a complex network structure is developed based on the transfer matrix method (TMM). The transfer matrices of single-input single-output, single-input dual-output, and dual-input single-output elastic elements are derived. The developed model introduces correction coefficients to represent the local separation effect at bolted connections caused by stiffness differences and local bending deformation. Vibration tests demonstrate that the proposed model outperforms existing TMM-based models in predicting resonant frequencies and mode shapes for the first three modes of the PVF. Compared with the finite element method, the proposed model greatly improves computational efficiency for the working mode while maintaining comparable accuracy. Validation of a PVF with a complex structure indicates that the developed modeling framework can be extended to other similar structures with elastic multi-input/multi-output elements and comparable bolted piezoelectric devices, thereby providing valuable support for structural design optimization and performance enhancement.

In this study, the working principle of the toroidal traveling-wave piezoelectric transducer is initially introduced, followed by proposing a method for arranging the piezoelectric excitation source of the hollow-type transducer, thereby facilitating the achievement of an optimal traveling wave. Consequently, based on the above arrangement criteria, a comprehensive structural design method of annular hollow-type traveling-wave piezoelectric transducer based on out-of-plane traveling-wave operation is summarized. In addition, to investigate the vibration characteristics of the transducer designed based on this method, a theoretical model of electromechanical coupling dynamics is established using the dynamic substructure method in conjunction with Hamilton's principle. The model holds broad applicability and provides valuable guidance for the design and optimization of hollow-type travelling wave piezoelectric transducers. Then the sensitivity analysis of the structural parameters of the transducer is carried out by the semi-analytical dynamic modeling method, and the motion trajectory of the particle on the tooth surface is also analyzed, which provides a theoretical basis for the subsequent parameter optimization design. Finally, the feasibility of the transducer structure design method and the accuracy of the developed dynamics model were subsequently validated through appropriate vibration measurement experiments conducted on the transducer prototype. The measured ideal mode shape and consistent elliptical motion confirmed the viability of the transducer design method, while comparing the results from vibration measurements with those obtained from theoretical model calculations affirmed the accuracy of the developed dynamic model. Comparison between theoretical calculations and measured vibrations shows a maximum difference rate of 8.3 % in stator working mode frequency and 4.1 % in amplitude calculation differences, confirming the validity of this dynamic model. Moreover, the proposed structural design method and corresponding semi-analytical dynamic model in this work are expected to provide significant guidance for the design and optimization of hollow-type annular traveling wave transducers.

Truss structures provide support and connection as essential components of spacecrafts. However, they are constantly disturbed and vibrated, which affects the pointing accuracy and operating stability. An active vibration isolation method for truss structures with embedded piezoelectric actuators (EPAs) is proposed in this study to address the challenges of excessive weight, large size, and limited effectiveness in vibration control equipment. Firstly, the EPA with a sandwich structure is designed and strategically embedded in the truss structure. Secondly, a novel modeling method is developed using the transfer matrix method (TMM) to effectively characterize complex beam structures including truss structures. Finally, a prototype is developed and the measurement system is constructed. The accuracy of the modeling is confirmed by vibration response experiments, with measurement results indicating that the discrepancies between theoretical predictions and experimental data remain within 5 %. Further validation of the EPAs for active vibration isolation is achieved through dedicated experiments, revealing a maximum isolation effect of -27.87 dB for longitudinal vibrations and -22.08 dB for bending vibrations. The experimental findings substantiate the promising application of proposed EPAs in enhancing active vibration isolation for truss structures, offering significant potential for improving the precision pointing and operational stability of space structures and spacecraft.

Piezoelectric composite plates are essential structural components in aerospace, medical devices, precision manufacturing, and robotics. Dynamic analysis is crucial for their optimization and design. Existing analytical plate theories fail to describe the electromechanical coupling effect under arbitrary boundary conditions, making the finite element method (FEM) the only viable approach. However, FEM entails high computational costs and operates as a black box, obscuring the underlying physical mechanisms. To address these challenges, this paper proposes a novel electromechanical coupled dynamic modeling method for analyzing the out-of-plane vibration of rectangular piezoelectric composite plates (RPCPs). First, the method transforms the two-dimensional system of the RPCPs into a one-dimensional lattice structure composed of piezoelectric composite beams. This simplification reduces the system from two dimensions to one. Subsequently, using the transfer matrix method (TMM), the model of the equivalent structure is established, enabling analysis of out-of-plane vibration characteristics under arbitrary boundary conditions. Finally, the finite element method (FEM) analyses and experiments were conducted on RPCPs with four different boundary conditions to validate the proposed modeling method. Comparison results demonstrate that the vibration results derived from the proposed model closely match both the FEM and experimental results. Additionally, the resonant frequencies calculated using the proposed model align more closely with experimental results than those obtained from FEM simulations, and the computational speed is 37.4 times faster than the FEM. This model offers an efficient approach for analyzing the out-of-plane vibration response of rectangular piezoelectric composite plates under arbitrary boundary conditions, providing strong theoretical support for the design and optimization of piezoelectric composite plate structures.

Sandwich single-phase-driven piezoelectric actuators have attracted increasing interest owing to their simple control circuits, flexible designs, and high output forces. However, there are challenges in constructing a standing-wave driving mode for sandwich single-phase-driven rotary piezoelectric actuators and in achieving bidirectional driving as well as an integrated structural and functional design, which limit their applications. To address these issues and meet the demands of the joint drive, a novel sandwich single-phase-driven rotary piezoelectric actuator is proposed in this study. The actuator stator has a beam-ring configuration, with dual rotors effectively integrated with a preload adjustment mechanism to solve the contact-warping problem of the cantilever joint and achieve an integrated structural and functional design of the joint drive. The standing-wave rotation drive and steering functions are realized through the special design of modes and unique arrangement of the upper and lower driving teeth. To reveal the dynamic characteristics of the stator, a universal electromechanical coupling dynamic model for the torsional-bending composite vibration of sandwich piezoelectric actuators was developed for the first time using the transfer matrix method, and the correctness of the dynamic model was verified using a prototype of the proposed stator. Finally, the structural design feasibility of the proposed piezoelectric actuator was verified through performance evaluation experiments on the actuator prototype. The proposed sandwich single-phase-driven rotary piezoelectric actuator lays the technical and theoretical foundations for achieving simple, fast, efficient, and precise driving and control of robotic joints.