Magnetic-induced deformation driving triboelectric sensor with dual-mode perception for magnetic field and contacting pressure.

Integrating magnetic field evasion and obstacle avoidance is crucial for the safe operation of intelligent robots, yet the limited sensitivity and discrete structure of magnetic field/pressure dual-mode sensors hinder their broader application. In this work, we present a dual-mode triboelectric sensor (DM-TS) that achieves noncontact magnetic field sensing and contact pressure sensing by incorporating ferrofluid as a triboelectric material. Under varying magnetic field intensities or directions, it redistributes along the magnetic field lines, modulating its contact area with spiked silicone rubber to generate distinct electrical signals for magnetic field sensing. The DM-TS exhibits a longitudinal magnetic field sensitivity of 11.35 V/T in the linear response region ranging from 63 ~ 277 mT, which is comparable to existing flexible magnetosensitive devices or commercial Hall effect sensors. For contact sensing, applied pressure deforms the silicone rubber with spike structures, altering the contact area between triboelectric layers and producing corresponding electrical outputs. The pressure sensitivity increases with the applied pressure range, reaching 370.56 mV/kPa within the 19.37-27.3 kPa range. As a proof-of-concept for intelligent robotic systems, the DM-TS has been integrated into an unmanned ground vehicle (UGV), successfully demonstrating simultaneous strong magnetic field evasion and obstacle avoidance.