Application of Structured and Directional Residuals for Fault Detection and Isolation on Permanent-Magnet DC Motor with Amplifier

Sensors and actuators are physical components often subjected to non‐permissible or unexpected deviations from nominal operating conditions. This paper discusses the application of additive fault detection and isolation (FDI) methods developed for linear and stationary systems on a nonlinear non‐stationary system consisting of an electronic amplifier with a DC motor. A temperature‐dependent viscous friction coefficient, as well as the non‐linearity induced by dry friction, makes the system nonlinear. Residuals were designed using two fundamental residual‐enhancement approaches: synthesis of structured residuals and synthesis of directional residuals. A comparative analysis of the results was performed applying four different techniques for residual transformation synthesis. The paper proposes suitable filtering and translation of the structured and directional residuals that enhance FDI, performance. A limiting factor in the application of directional residuals, relating to the number of different faults, which may have independent directions during FDI, is illustrated. The entire procedure is demonstrated on a simple model of a permanent‐magnet DC motor with a suitable amplifier. This laboratory system is often encountered in electrical engineering laboratories, and accordingly, the results can be used as useful educational material for student training in FDI.