Combining 4D-printed bilayer actuators with the slit structure and sensing capabilities unique to the process further promotes the use of 4D printing in biomedical devices, human-computer interaction, intelligent self-protection devices, and humanoid robots. In this study, we propose an adaptive multifunctional strain sensor (AMSS) 4D printing strategy based on the shape memory properties of polylactic acid (PLA), a bioslit structural sensing unit, and a bi-directional deformation design of a bilayer structure. The obtained AMSS was shown to have excellence sensitivity to strain, mechanical, and temperature stimuli. In particular, thanks to the 3D printed slit structure and phase transition properties of the PLA printing layer, the AMSS macro-microstructure can be precisely tuned, and its sensing performance is shown to be intelligently programmable. The built-in structural design-induced macro-deformation enables AMSS to adaptively fit human joint surfaces for full-range human motion recognition. In addition, the close correlation of strain-sensing during AMSS shape transformation enables position self-sensing and strain self-sensing of AMSS. Further, through the integration and separation of resistive signals, we are able to recognize temperature and mechanical stimuli. Finally, we integrate the wireless sensing module into the AMSS to improve the portability and wearability of the sensor.

中文翻译：

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具有可编程传感特性的 4D 打印多功能可穿戴应变传感器

将4D打印双层执行器与工艺特有的狭缝结构和传感能力相结合，进一步推动4D打印在生物医学设备、人机交互、智能自我保护设备和人形机器人等领域的应用。在这项研究中，我们提出了一种基于聚乳酸（PLA）的形状记忆特性、生物狭缝结构传感单元和双层结构的双向变形设计的自适应多功能应变传感器（AMSS）4D打印策略。所获得的 AMSS 对应变、机械和温度刺激具有优异的敏感性。特别是，得益于3D打印的狭缝结构和PLA打印层的相变特性，AMSS宏观微观结构可以精确调节，并且其传感性能显示出可智能编程。内置的结构设计引起的宏观变形使AMSS能够自适应地贴合人体关节表面，实现全方位的人体运动识别。此外，AMSS形状变换过程中应变传感的密切相关性使得AMSS能够实现位置自传感和应变自传感。此外，通过电阻信号的集成和分离，我们能够识别温度和机械刺激。最后，我们将无线传感模块集成到AMSS中，以提高传感器的便携性和耐磨性。