Hard fault refers to instantaneous bigger step or mutations of the normal sensors' outputs, including step fault or pulse fault of sensors.
Figure 6 shows that when the step fault occurs to N1, residuals of the four sensors all exceed their corresponding thresholds from 2500 s to time 4000 s.
The step fault and slope fault are selected to analyze the fault type detection performance of the proposed fault detection method.
During 100~200 sampling points, the constant error (to form the step fault) and slope error are added in the sensor signals, respectively.
According to Table 1, the measured Lipschitz exponents with respect to step fault and slope fault approximate to their ideal values, respectively.