Load Sensing Bearings for Automotive Applications Based on Addressed Fiber Bragg Structures

The paper presents a microwave-photonic sensor system (MWPSS) for load sensing wheel hub bearings of the vehicle. The proposed MWPSS is based on the addressed fiber Bragg structures (AFBS) with two symmetrical phase shifts. The system utilizes three similar AFBS embedded in the outer ring of the bearing. All AFBS have equal bandwidths, the same central Bragg wavelength, and unique address frequency spacing, thus realizing the microwave-photonic measurement methods and providing their address. Two of the AFBS serve for strain measurement, and the third 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) without usage of an optical interrogator. These values are the input parameters for the wheel loads estimation, which is used for vehicle dynamics control.