Prognostics for Autonomous Deep-Space Habitat Health Management under Multiple Unknown Failure Modes
Authors: Benjamin Peters, Ayush Mohanty, Xiaolei Fang, Stephen K. Robinson, Nagi Gebraeel
Organizations: University of Texas at Rio Grande Valley, Edinburg, TX 78539, USA · Georgia Institute of Technology, Atlanta, GA 30332, USA · North Carolina State University, Raleigh, NC 27607, USA · University of California, Davis, Davis, CA 95616, USA
Deep-space habitats (DSHs) are safety-critical systems that must operate autonomously for long periods, often beyond the reach of ground-based maintenance or expert intervention. Monitoring system health and anticipating failures are therefore essential. Prognostics based on remaining useful life (RUL) prediction support this goal by estimating how long a subsystem can operate before failure. Critical DSH subsystems, including environmental control and life support, power generation, and thermal control, are monitored by many sensors and can degrade through multiple failure modes. These failure modes are often unknown, and informative sensors may vary across modes, making accurate RUL prediction challenging when historical failure data are unlabeled. We propose an unsupervised prognostics framework for RUL prediction that jointly identifies latent failure modes and selects informative sensors using unlabeled run-to-failure data. The framework consists of two phases: an offline phase, where system failure times are modeled using a mixture of Gaussian regressions and an Expectation-Maximization algorithm to cluster degradation trajectories and select mode-specific sensors, and an online phase for real-time diagnosis and RUL prediction using low-dimensional features and a weighted functional regression model. The approach is validated on simulated DSH telemetry data and the NASA C-MAPSS benchmark, demonstrating its ability to identify unknown failure modes, select mode-specific informative sensors, and accurately predict RUL.
Figures & tables
ASGL =
Adaptive Sparse Group Lasso
CA =
Covariate-Adjusted
CES =
Complex Engineering System
C-MAPSS =
Commercial Modular Aero-Propulsion System Simulation
CDLL =
Complete-Data Log-Likelihood
DSH =
Deep-Space Habitat
ECLSS =
Environmental Control and Life Support System
Table 1
Figure 1: Example of a deep-space habitat with multiple subsystems. The health of each subsystem is monitored by a subset of onboard sensors. The subset of informative sensors varies for different failure modes.
Figure 2: Overview of the proposed prognostics framework for deep-space habitats
Figure 3: Case study 1 data: Signals in sensors 1, 3, 5, 19 (rows 1, 2, 3, 4 respectively) for FM 1 (blue) and FM 2 (red) under different SNRs: [2, 5], [5, 8], and [8, 11] (columns 1, 2, 3 respectively)
Figure 4: CV Error for (a) SNR [2,5], (b) SNR [5,8], and (c) SNR [8,11]
SNRpk
[2,5]
[5,8]
[8,11]
λ
0.0288
0.0288
0.0288
α
1
1
0.75
Table 2: Tuning parameter selection for Case Study 1
SNRpk
FM
Accuracy
Sensors Selected
[2, 5]
1
0.5500
1:20
2
0.9125
1:20
[5, 8]
1
0.8875
1:20
2
0.8313
1:20
[8, 11]
1
0.8375
1,3:20
2
0.8438
1:3,5:20
Table 3: MGR-ASGL performance for case study 1
SNRpk
FM 1
FM 2
Sensor ID
l2 -norm
Sensor ID
l2 -norm
5
1.464
9
1.561
[2, 5]
12
1.159
7
1.456
16
1.104
19
0.554
19
0.723
6
0.373
12
1.886
9
2.623
Table 4: l2 -norms of four most informative sensors for FM1 & FM2
Figure 5: Prediction error (in % ) for all test systems of case study 1 under three different SNRs, i.e., [2, 5], [5, 8], and [8, 11]
Figure 6: The system diagram used in Case Study 2, adapted from [ 70 ]
Sensor ID
Sensor Name
Functionality
1
T2
Total temperature at fan inlet
2
T24
Total temperature at LPC outlet
3
T30
Total temperature at HPC outlet
4
T50
Total temperature at LPT outlet
5
P2
Pressure at fan inlet
6
P15
Total pressure in bypass-duct
Table 5: Sensors used in case study 2 (C-MAPPS [ 71 ] )
Figure 7: Sensor data used for the offline step in case study 2. HPC failure (blue), Fan failures (red)
Sensor ID
2
3
4
7
8
9
11
12
13
14
15
17
20
21
FM 1
0.266
0.584
0.897
0
0.117
0.545
0
0
0.90
0.148
0.501
0.230
0
0.116
FM 2
0
0
0.033
0.877
0
0.291
0
1.148
0
0.119
0
0.042
0.573
0.318
Table 6: Sensor Selection for Case Study 2
Figure 8: Average Prediction error ( % ) in case study 2
Figure 9: Prediction error ( % ) for different RUL intervals in case study 2
Department of Industrial and Systems Engineering, University of Florida, Gainesville, USA · School of Forest, Fisheries, and Geomatics Sciences, University of Florida, Gainesville, USA
Fowler School of Engineering, Chapman University, Orange, CA 92866 USA · Department of Statistics, Grand Valley State University, Allendale, MI 49401 USA