Estimating Normal and Tangential Forces in Tires through Ionic Liquid-Based Flexible Sensors

ABSTRACT Measuring normal and tangential forces on tires is crucial for enhancing tire performance under various road conditions and environmental settings. The measurement of these forces has been challenging because of limitations in sensing technology related to rigidity, durability, and sensitivity. This research introduces an innovative method that utilizes flexible sensors made of ionic liquid to address the limitations. Through the utilization of the distinctive properties of ionic liquids, such as their flexibility, enhanced sensitivity, and exceptional stability, a multilayer sensor has been manufactured. This sensor consists of carbon nanotube electrodes, ionic liquid dispersed in polymer creating a pressure-sensitive layer, and polymer insulating layers. The focus of this study is on the development of the sensor and understanding how its output changes under varying normal and tangential forces. Preliminary testing has shown that the sensor exhibits distinct and measurable responses to both force components, highlighting its potential for accurate force differentiation. The research evaluates the sensor’s performance and efficacy under varied force conditions, demonstrating its capability to accurately measure both normal and tangential forces. Such measurements are vital for the development of intelligent tires, offering deeper insights into critical tire parameters such as braking or traction force coefficients, contact patch characteristics, vehicle dynamics, and road surface conditions, leading to the improvement of safety, efficiency, and performance of tires.