Origami-Mediated Low-Voltage Electret Soft Robotic Actuators for Human-Machine Haptic Interfaces

Soft robotic actuators often require relatively high driving voltages, which limit their portability, safety, and compatibility with compact electronic systems in wearable haptic interfaces. Achieving strong electromechanical coupling at low voltage while maintaining mechanical compliance remains a key challenge for soft actuator design. Here, we present an origami-mediated low-voltage electret soft robotic actuator that integrates mechanical compliance and electrical functionality within a symmetric multilayer architecture. Two double-layer fluorinated ethylene propylene (FEP) electret films with enclosed micro air-cavity arrays are positioned on both sides of a folded copper origami structure. The origami layer acts as a compliant electrode with a tunable spring-like response, while the air-cavity arrays promote high surface potential and stable charge retention. By jointly optimizing electret charging and origami stiffness, the actuator produces perceptible vibrotactile feedback at driving voltages as low as 20 V and supports reliable tactile digital recognition at 70 V using a 7-segment actuator array. Stable output and durability are maintained over 10 h of high-frequency operation. Application in a virtual reality piano training task further demonstrates statistically significant improvements in motor learning performance and perceived immersion. This approach offers a compelling pathway toward compact, low-voltage human-machine haptic interfaces with robust tactile performance.