Array-less touch position identification based on a flexible capacitive tactile sensor for human-robot interactions

Abstract

For human-robot interactive systems, physical touch identification is essential for security and intelligence enhancement. Flexible tactile sensor with a simple structure and minimal peripheral electric connections will benefit various applications where the contact information is crucial. However, it is still hard to balance the full flexibility, large area, minimal electrical connection and easy fabrication in existed tactile sensing systems. In this letter, a novel positioning method based on a flexible capacitive tactile sensor is introduced. The tactile sensor contains two layers of screen-printed flexible electrodes and an ionic gel membrane in the middle to form electrostatic double layer capacitors (EDLCs). Only four points of the top layer electrode are used in the measurement to identify the touch position by measuring the voltage variation in real-time. Taking advantages of the electric potential re-distribution induced by the EDLC variation from the touch pressure, a calculation method for touch position recognition is tested based on experimental data. The developed method has no dependency on complex fabrication, redundant electric circuit or sensing unit arrays, which owns a promising future in various application fields, such as intelligent robotics, biomedical devices, and wearable equipment.