Tire Strain Measurement System Based on Addressed FBG-Structures

The work presents a concept of microwave-photonic sensor system (MWPSS) for real-time measurement of vehicle tire strain. The proposed MWPSS is based on the addressed fiber Bragg structures (AFBS) with two symmetrical π-phase shifts (2π-FBG). The system utilizes two similar 2π-FBGs with equal bandwidths, the same central Bragg wavelength, and unique address frequency spacing, thus realizing the microwave-photonic measurement methods and providing their address. One of the 2π-FBGs serves for strain measurement, and the second one takes into account the effects of temperature variation. Address frequency analysis of the multiplicative optical response allows to define the central Bragg frequency shift of each sensor and to correlate it with the value of the influencing physical fields (strain and temperature). These values are the input parameters for the estimation system of tire-road contact characteristics and vehicle dynamics control.