Compact high resolution piezoceramic metastructure actuator with optimized multiple electro-mechanical modes

Simultaneously generating various motion modes in piezoelectric structures is highly desirable for smart multifunctional actuators featuring high resolution and high speed, which are difficult to achieve simultaneously. Traditional piezoelectric actuators are constructed by bonding several piezoelectric and non-piezoelectric stacks, leading to complicated structures. This study reports a compact smart actuator designed from a slice of pure piezoceramic metastructure. The metastructure consists of asymmetrically connected units, enabling simultaneous bending and stretching modes under a single signal excitation. Through parametric design for multiple deformation modes, the actuator achieves stable stepping motion with both a high displacement resolution of 3.32 nm and a broad driving-speed range from 1.14 μm s⁻¹ to 2.00 mm s⁻¹. Furthermore, with dynamic friction control based on contact-foot trajectory optimization, nearly zero backward motion and enhanced stepping displacement are achieved, enabling larger velocities. This work proposes a novel inertial actuator based solely on a pure piezoceramic metastructure, advancing compact smart high-performance actuators with both high resolution and high speed.