Optical monitoring system

A monitoring system for an electric vehicle that draws current from a conductor by means of current collector means which contacts a conductor in operation of the vehicle, the system comprising:

• a plurality of sensor module means distributed at spaced intervals throughout the current collector means, wherein each sensor module means comprises a plurality of FBG (Fibre Bragg Grating) sensor means orientated so as to be at least generally co-planar with a surface of the current collector means that contacts the conductor in operation of the vehicle, each said sensor module means being comprised only of FBG sensor means that are responsive in use to both temperature and strain, the sensor means of each said sensor module means being arranged in a geometric pattern that compensates for temperature induced wavelength changes in the FBG sensor means of each sensor module means;
• optical source means for illuminating each said sensor module means;
• optical coupler means configured to optically connect said optical source means to each said sensor module means;
• and
• optical signal interpretation means configured to receive optical signals from each said sensor module means via said optical coupler means, said optical signals being generated by said sensor module means in response to illumination of said sensor module means by said optical source means, said optical signal interpretation means being configured to capable of determining from said optical signals a temperature-independent strain measurement for each said sensor module means.

A monitoring system for an electric vehicle that draws current from a conductor by means of a current collector that contacts a conductor in operation of the vehicle, the system comprising:

• a plurality of sensor modules for distribution at spaced intervals throughout the current collector, wherein each sensor module comprises three FBG (Fibre Bragg Grating) sensors orientated so as to be at least generally co-planar with a surface of the current collector that contacts the conductor in operation of the vehicle, each said module being comprised only of FBG sensors that are responsive in use to both temperature and strain, the sensors of each said sensor module being arranged in a triangular pattern that compensates for temperature induced wavelength changes in the FBG sensors of each sensor module, each said sensor of each said sensor module being at approximately 60 degrees to neighbouring sensors of that sensor module;
• an optical source for illuminating each said sensor module;
• an optical coupler configured to optically connect said optical source to each said sensor module;
• and
• an optical signal interpretation module configured to receive optical signals from each said sensor module via said optical coupler, said optical signals being generated by said sensor modules in response to illumination of said sensor modules by said optical source, said interpretation module being configured to be capable of determining from a mathematical correlation of said optical signals from the plurality of FBG sensors of each said sensor module a temperature-independent strain measurement for each said sensor module.