Rapid-Response and Low-Detection-Threshold Capacitive 3D Force Tactile Sensor Based on an Inverted Frustum Structure

In the burgeoning field of electronic skin (e-skin) and wearable technology, the development of flexible and sensitive tactile sensors is of paramount importance. This paper presents the fabrication and characterization of a capacitive flexible tactile sensor with an inverted frustum structure, designed to address the limitations of existing sensors in terms of sensitivity, response speed, and durability. The sensor was developed using a combination of 3D-printing and layer-by-layer (LBL) techniques, leveraging the benefits of conductive silver adhesive and silicone rubber for enhanced performance. The fabrication process involved the use of COMSOL Multiphysics for simulation, followed by 3D printing of molds and curing of silicone rubber at specific temperatures to form the sensor components. Electrical conductivity was ensured through the application of conductive silver adhesive, and the assembly was finalized through vacuum drying. Key findings from the study include the sensor’s high sensitivity to both normal and tangential forces, with a sensitivity of 0.2 N –1 in the 0–4 N range and 0.11 N –1 from 4 to 15 N under normal force, and a rapid response time of 25 ms. The sensor also demonstrated excellent mechanical durability with a hysteresis error of 4.8% and maintained a stable performance across a wide temperature range, indicating its robustness and reliability. Furthermore, the sensor showed potential in applications such as human–computer interaction and binary encoding, highlighting its versatility. This study significantly contributes to the field by presenting a sensor with good sensitivity and rapid response, along with excellent mechanical durability and temperature stability. The findings pave the way for the development of advanced e-skin and wearable devices that can provide real-time monitoring and feedback in various applications.