Optimal Cost-Effective Maintenance Policy for a Helicopter Gearbox Early Fault Detection under Varying Load

Table 4

Comparison of RUL prediction and RE using different models.

File number	ARL	RUL		RE
		HSMM	HMM	HSMM	HMM
1	19.34	19.801	19.800	0.024	0.024
2	19.206	19.013	19.942	0.010	0.038
3	19.071	18.203	19.801	0.046	0.038
4	18.937	18.019	19.689	0.049	0.040
5	18.803	16.981	19.332	0.097	0.028
6	18.669	15.002	19.340	0.196	0.036
7	18.535	13.200	19.185	0.288	0.035
⋮	⋮	⋮	⋮	⋮	⋮
88	7.662	8.013	18.343	0.045	1.394
89	7.527	8.003	18.271	0.063	1.427
90	7.393	7.830	18.001	0.059	1.435
91	7.259	7.482	7.701	0.031	0.061
92	7.125	7.450	7.645	0.045	0.073
93	6.990	7.308	7.632	0.046	0.091
94	6.856	7.225	7.545	0.054	0.100
95	6.722	7.031	7.416	0.046	0.103