Abstract: A system includes one or more processors and a resonant sensor that contacts oil within an engine of a vehicle system. The sensor generates electrical stimuli at different times during an operational life of the engine. Each electrical stimulus has multiple different frequencies applied to the oil. The one or more processors receive electrical signals representing impedance responses of the oil to the electrical stimuli. The one or more processors determine a concentration of a polar analyte in the oil at the different times based on the impedance responses and calculate a degradation value for the engine based on the polar analyte concentration. Responsive to the degradation value exceeding a designated degradation threshold, the one or more processors at least one of schedule maintenance for the vehicle system, provide an alert to schedule maintenance for the vehicle system, or prohibit operation of the vehicle system until maintenance is performed.

Abstract: A system includes one or more processors and a resonant sensor that contacts oil within an engine of a vehicle system. The sensor generates electrical stimuli at different times during an operational life of the engine. Each electrical stimulus has multiple different frequencies applied to the oil. The one or more processors receive electrical signals representing impedance responses of the oil to the electrical stimuli. The one or more processors determine a concentration of a polar analyte in the oil at the different times based on the impedance responses and calculate a degradation value for the engine based on the polar analyte concentration. Responsive to the degradation value exceeding a designated degradation threshold, the one or more processors at least one of schedule maintenance for the vehicle system, provide an alert to schedule maintenance for the vehicle system, or prohibit operation of the vehicle system until maintenance is performed.

Abstract: A disclosed apparatus comprises an adaptive observer that has an adaptive element to augment a linear observer to enhance its ability to control a nonlinear system. The adaptive element comprises a first, and optionally a second, nonlinearly parameterized neural network unit, the inputs and output layer weights of which can be adapted on line. The adaptive observer generates the neural network units' teaching signal by an additional linear error observer of the nominal system's error dynamics. The adaptive observer has the ability to track an observed system in the presence of unmodeled dynamics and disturbances. The adaptive observer comprises a delay element incorporated in the adaptive element in order to provide delayed values of an actual output signal and a control signal to the neural network units.