Piezoelectric Actuators and Ultrasonic Motor Technologies

Piezoelectric actuators exploit the inverse piezoelectric effect to convert electrical signals into mechanical displacement with nanometre-scale resolution, high bandwidth and immunity to electromagnetic interference. They encompass a variety of drive principles, including stick–slip inertia drives, resonance-drive ultrasonic motors and piezo-walk mechanisms. Ultrasonic motors generate motion by inducing high-frequency vibrations in a stator, transferring energy to a rotor or slider through frictional coupling. Such devices combine compact form factors and high force or torque density, making them ideal for precision positioning in microscopy, robotics, aerospace and medical systems. Recent advances in materials, microfabrication and control schemes have improved efficiency, reduced acoustic noise and extended operational lifespan. Ongoing challenges include minimising friction-induced wear, achieving low-velocity smooth motion and integrating multifunctional sensing. The interplay between actuator design, material selection and drive electronics continues to drive global innovation, enabling miniature robots, multi-degree-of-freedom (DOF) manipulation platforms and micromachining systems with unprecedented precision and adaptability.

Research from Nature Portfolio

Recent studies have demonstrated a direct-drive rigid piezoelectric robotic hand featuring four piezoelectric fingers and twelve motion DOFs. Constructed entirely from functional piezoceramic elements, the device delivers linear and rotary manipulations of plates, cylinders and spheres across scales from micrometres to centimetres. Pre-programmed hand gestures enable ten distinct objects to undergo high-precision motion without auxiliary gear trains or electromagnetic motors. Integrated within a compact system, this robotic hand achieves submicrometre positioning accuracy and rapid response, pointing to new directions for ultra-precision multi-DOF manipulators in biomedical assembly, optical alignment and micro-assembly tasks.

Piezoelectric Actuators and Ultrasonic Motor Technologies publication trend

The graph below shows the total number of articles in piezoelectric actuators and ultrasonic motor technologies across all publications each year (not limited to Nature Index journals).

Technical terms

Inverse piezoelectric effect: Generation of mechanical strain in certain crystals upon application of an electric field.

Ultrasonic motor: A motor that converts high-frequency vibrations into continuous or stepping motion via frictional contact.

Stick–slip: A motion principle where alternating static friction and rapid sliding produce incremental displacement.

Travelling wave: A vibration mode in which a progressive wave propagates around a stator to induce rotor movement.

Flexure hinge: A compliant mechanical element that permits precise angular motion through elastic deformation.

Degree(s) of freedom (DOF): Independent parameters that define the position and orientation of a mechanism or object.

References

1. Piezo-actuated smart mechatronic systems for extreme scenarios. International Journal of Extreme Manufacturing (2024).
2. Piezo robotic hand for motion manipulation from micro to macro. Nature Communications (2023).
3. Developments and Challenges of Miniature Piezoelectric Robots: A Review. Advanced Science (2023).
4. A Symmetric-Actuating Linear Piezoceramic Ultrasonic Motor Capable of Producing a Scissoring Effect. Research (2023).
5. Piezoelectric Motors, an Overview. Actuators (2016).
6. A Method to Realize Low Velocity Movability and Eliminate Friction Induced Noise in Piezoelectric Ultrasonic Motors. IEEE/ASME Transactions on Mechatronics (2020).