🤖 AI Summary
Soft microrobots face a fundamental trade-off between the high brittleness of piezoceramic actuators (e.g., PZT) and the low bandwidth of polymeric actuators. Method: This work proposes a voltage-parallel multilayer piezoelectric actuator based on polyvinylidene fluoride (PVDF), integrating a thickness–layer-count co-optimized electromechanical performance model, thin-film stacking fabrication, and resonant driving. Contribution/Results: The design achieves efficient electromechanical transduction at low drive voltages while preserving flexibility: free deflection >3 mm, blocking force ≈20 mN, and operational bandwidth >500 Hz—effectively bridging the performance gap between rigid PZT and soft polymer actuators. Integrated into a planar microrobot, the actuator demonstrates robust disturbance-rejection locomotion, thereby advancing the design paradigm and application scope of soft microrobotic actuators.
📝 Abstract
Multilayer piezoelectric polyvinylidene fluoride (PVDF) actuators are a promising approach to enhance performance of soft microrobotic systems. In this work, we develop and characterize multilayer PVDF actuators with parallel voltage distribution across each layer, bridging a unique design space between brittle high-force PZT stacks and compliant but lower-bandwidth soft polymer actuators. We show the effects of layer thickness and number of layers in actuator performance and their agreement with a first principles model. By varying these parameters, we demonstrate actuators capable of >3 mm of free deflection, >20 mN of blocked force, and >=500 Hz, while operating at voltages as low as 150 volts. To illustrate their potential for robotic integration, we integrate our actuators into a planar, translating microrobot that leverages resonance to achieve locomotion with robustness to large perturbations.