Simulation and theory for wiring compaction of robot skin tactile sensor by frequency-selective triboelectric-piezoelectric filters

Robots are increasingly equipped with different sensors to better identify things and interact with their environment. One such sensor is the ability to sense and receive information through touch. A significant challenge in designing tactile sensors is to create a larger and more complex network of electrical connections to cover larger partitioned surface areas, necessitating a more compaction for electrical connections. In this study, we try to reduce the number of these array connections by designing a novel triboelectric-piezoelectric pressure sensors that will function as electromechanical frequency-selective filters. The sensor cell units are created in the form of various disk-shape layers with a basic double-lamina layers, a triboelectric lamina placed over a piezoelectric lamina. The triboelectric layer, being soft, is used for static pressure measurement and more sensitivity enhancement. In addition, an electromechanical frequency-selective filter is generated by altering geometric dimensions of that lamina, such as the radius and/or thickness. An applied pressure is calculated by measuring the electric current and the cell unit admittance. The advantage of using piezo-layer geometric manipulation for generating different operating resonant frequencies is that it is a simpler design task as compared to alter the cell electrical properties, which is the focus of previous research. In this work, a theoretical model and numerical simulations are employed to obtain the electromechanical admittance of a set of three unit cell tactile sensors.