Three-dimensional force sensing has attracted increasing attention due to the rising application requirements from smart robots. Herein, we report a flexible three-dimensional force sensor with an interlocked structure as bionic human skin, which consists of flexible silicone substrate and polymer composite materials. Surface piezoresistive layer is patterned through electrospray and laser direct writing. The sensing mechanism is based on the contact resistance changes from three interlocked hemispheres units from either the normal force or the shear force. Shear force directional detection is rendered through three-axis structural arrangement in-plane. As a result, the sensor displays a normal force sensitivity of 6.33 kPa −1 , response time of 59 ms, and shear force angular resolution of below 30°. The manufacturing method is amenable for minimized sensor array fabrication. Further application is demonstrated with a mechanical arm for gripping objects, where the sensor provides in-time feedback for precise grasping.
Flexible pressure sensors play a vital role in advancing the Internet of Things (IoT). However, piezoelectric sensors are limited in static pressure detection and suffer in achieving high flexibility and high sensitivity simultaneously, while piezoresistive sensors typically have slow response speeds and insensitive high-frequency detection ability. Here, we select a novel basalt fiber fabric (BFF) that can withstand high temperatures exceeding 1000 °C as a new substrate to enable one-step fabrication of piezoelectric layer based on coherently grown Pb(Zr 0.52 Ti 0.48 )O 3 (PZT) thin films via a simple dipping method. The high piezoelectric coefficient g 33 of 362.5 mV·m·N −1 and the unique core-sheath structure induced stress concentration on the PZT sheath enable the flexible piezoelectric layer (bending radius < 1.45 mm) to exhibit high sensitivity (voltage sensitivity of 2.766 V/kPa within the range of 0.11–11.11 kPa) and fast response speed (11 ms). The piezoresistive layer consisting of a three-dimensional porous elastic carbon nanotube-polyurethane sponge provides a detection range comparable to piezoelectric layer (0.11–66.67 kPa). A dual-mode flexible pressure sensor (DMFS) has been developed by integrating the piezoelectric layer with the piezoresistive layer. The DMFS exhibits an extended detection range compared to previous dual-mode pressure sensors, rapid response speed, and high sensitivity, which enables simultaneous detection of both dynamic and static pressures. The DMFS can be used for keyboard and movement posture recognition, which has significant application prospects in human-machine interaction.
危险品化学品经营许可证（带存储）