Stator-Winding Incipient Shorted-Turn Fault Detection for Motor System in Motorized Spindle Using Modified Interval Observers

As an important part of the power source, the motorized spindle is considered as the components in the high-end computer numerical control (CNC) machine tools, which is required as special attention to avoid expensive production shutdown due to the appearance of massive failures. Therefore, it is necessary to detect the incipient fault of the motorized spindle by establishing an appropriate model. This article presents a scheme for detecting the stator-winding incipient shorted-turn fault of the motor system in the motorized spindle. As the cornerstone of the model-based fault detection scheme, the electromagnetic coupling motor model in the motorized spindle with the stator-winding incipient shorted-turn fault under $dq$ coordinate is given. In the presence of electromagnetic disturbance, two aspects can make the stator-winding shorted-turn fault of the motor in motorized spindle detected earlier. First, the modified interval observer based on the established mathematical model of the motor in the motorized spindle has more design freedom than the Luenberger interval observer, which can make the residual interval generated in the optimization process have better performance and a wider range of applications. Second, the $l_{1}/H_{\infty }$ performance is introduced in the process of residual interval generation, which can make it have better electromagnetic disturbance robustness and incipient fault sensitivity. The effectiveness of the proposed scheme is illustrated by numerical simulation and is further validated by lab experiments on a 9.8-kW motorized spindle test rig.