Laser-induced graphene-based corrugated bimodal sensor for strain and contact monitoring in wearables and intelligent robotics

Abstract

Multimodal flexible sensors play a pivotal role in wearable health monitoring and robotic end-effector perception. However, achieving concurrent detection of diverse motion states and multiple physical signals within a single device remains a challenge. Herein, a corrugated bimodal sensor (CBS) is proposed for strain and contact sensing. Fabricated via a one-step laser-induced graphene (LIG) patterning process, the strain and contact units are highly integrated onto a polyimide (PI) film, enabling synchronous monitoring of contact and strain signals. In contrast to the intrinsically limited stretchability of the PI film, the corrugated piezoresistive graphene strain unit achieves an exceptional combination of mechanical softness, high tensile strain (10%), and a high gauge factor of 3.01. It exhibits rapid response (389 ms) and excellent stability during stretching and bending. The triboelectric contact unit, enhanced by laser-ablated microgrooves, delivers a maximum output voltage of 55 V, enables material discrimination, and provides proximity sensing up to ≈100 mm, with a fast response time of 40 ms. Notably, both sensing units are capable of pressure monitoring, offering a high pressure sensitivity of 6.02 V kPa⁻¹ and a wide detection range of 0.7–83 kPa. By fusing proximity, contact, and strain signals, the CBS can be worn on the human body for real-time motion and contact analysis as well as biomechanical energy harvesting, facilitating health status assessment. When integrated onto a robotic gripper, it empowers intelligent functions such as collision avoidance, grasping state monitoring, and object recognition. This work provides a versatile hardware platform for next-generation wearables and intelligent robotics, where multi-information fusion is essential.