Sensor fusion by using a sliding observer for an underwater breathing system

This paper addresses the sensor fusion problem applied to an underwater breathing apparatus. In such systems hardware redundancy is used for safety reasons: in order to overcome any dangerous situations eventually coming from sensor faults, the measurement is taken by using three sensors that measure the same variable (oxygen partial pressure). Thus a sensor fusion scheme is needed in order to feed-back the measurement for controlling purposes. The work presents a fusion algorithm that uses a sliding mode observer for taking into account model information, and combine the different measurements by looking at how they behave with respect to the observer prediction. A forgetting factor approach is used for making more reactive the algorithm. Extensive simulations show the effectiveness of the proposed solution comparing results with a more traditional approach like the voting logic.