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The emergence of tougher environmental legislations and ever increasing demand for increased ride comfort, fuel efficiency, and low emissions have triggered exploration and advances towards more efficient vehicle gearbox technologies. The growing complexity and spatial distribution of such a mechatronic gearbox demands precise timing and coordination of the embedded electronics, integrated sensors and actuators as well as excellent overall reliability. The increased gearbox distributed systems have seen an increased dependence on sensors for feedback control, predominantly relying on hardware redundancy for faults diagnosis. However, the conventional hardware redundancy has disadvantages due to increased costs, weight, volume, power requirements and failure rates. This paper presents a virtual position sensor-based Fault Detection, Isolation and Accommodation (FDIA), which generates an analytical redundancy for comparison against the actual sensor output.

Electro-hydraulic actuated systems are widely used in industrial applications due to high torque density, higher speeds and wide bandwidth operation. However, the complexities and the parametric uncertainties of the hydraulic actuated systems pose challenges in establishing analytical mathematical models. Unlike electro-mechanical and pneumatic systems, the nonlinear dynamics due to dead band, hysteresis, nonlinear pressure flow relations, leakages and friction affects the pressure sensitivity and flow gain by altering the system's transient response, which can introduce asymmetric oscillatory behavior and a lag in the system response. The parametric uncertainties make it imperative to have condition monitoring with in-built diagnostics capability. Timely faults detection and isolation can help mitigate catastrophic failures. This paper presents a signal-based fault diagnostic scheme for a gearbox hydraulic actuator leakage detection using the wavelet transform.

The lubricant wear and degradation is a major cause of failure in industrial machines such as engines, pumps and gearboxes. This is primarily due to contaminants such as metal debris particles and depletion of the chemical and physical properties. This paper presents a low cost, multi-functional sensor for real-time monitoring of both oil level and the debris particles in oil lubricants for a gearbox application. The sensor system achieves a micrometer-order resolution (37.5 μm), high linearity (< 0.5 mm non-linearity) and insensitivity to viscosity changes due to wide temperature fluctuations from −40 °C to 135 °C, and is designed for ease of manufacturing and application in harsh transmission environment. The synergy from simultaneous data analysis from a multi-functional sensor has been demonstrated both qualitatively and quantitatively using mathematical analysis, computer simulation and physical experiments.