An Autoregressive-Based Motor Current Signature Analysis Approach for Fault Diagnosis of Electric Motor-Driven Mechanisms
Maintenance strategies such as condition-based maintenance and predictive maintenance of machines have gained importance in industrial automation firms as key concepts in Industry 4.0. As a result, online condition monitoring of electromechanical systems has become a crucial task in many industrial...
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MDPI AG
2025-02-01
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| Online Access: | https://www.mdpi.com/1424-8220/25/4/1130 |
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| author | Roberto Diversi Alice Lenzi Nicolò Speciale Matteo Barbieri |
| author_facet | Roberto Diversi Alice Lenzi Nicolò Speciale Matteo Barbieri |
| author_sort | Roberto Diversi |
| collection | DOAJ |
| description | Maintenance strategies such as condition-based maintenance and predictive maintenance of machines have gained importance in industrial automation firms as key concepts in Industry 4.0. As a result, online condition monitoring of electromechanical systems has become a crucial task in many industrial applications. Motor current signature analysis (MCSA) is an interesting noninvasive alternative to vibration analysis for the condition monitoring and fault diagnosis of mechanical systems driven by electric motors. The MCSA approach is based on the premise that faults in the mechanical load driven by the motor manifest as changes in the motor’s current behavior. This paper presents a novel data-driven, MCSA-based CM approach that exploits autoregressive (AR) spectral estimation. A multiresolution analysis of the raw motor currents is first performed using the discrete wavelet transform with Daubechies filters, enabling the separation of noise, disturbances, and variable torque effects from the current signals. AR spectral estimation is then applied to selected wavelet details to extract relevant features for fault diagnosis. In particular, a reference AR power spectral density (PSD) is estimated using data collected under healthy conditions. The AR PSD is then continuously or periodically updated with new data frames and compared to the reference PSD through the Symmetric Itakura–Saito spectral distance (SISSD). The SISSD, which serves as the health indicator, has proven capable of detecting fault occurrences through changes in the AR spectrum. The proposed procedure is tested on real data from two different scenarios: (i) an experimental in-house setup where data are collected during the execution of electric cam motion tasks (imbalance faults are emulated); (ii) the Korea Advanced Institute of Science and Technology testbed, whose data set is publicly available (bearing faults are considered). The results demonstrate the effectiveness of the method in both fault detection and isolation. In particular, the proposed health indicator exhibits strong detection capabilities, as its values under fault conditions exceed those under healthy conditions by one order of magnitude. |
| first_indexed | 2025-03-14T14:51:02Z |
| format | Article |
| id | doaj.art-45f14198c5144042804c80f386f6e195 |
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| issn | 1424-8220 |
| language | English |
| last_indexed | 2025-03-14T14:51:02Z |
| publishDate | 2025-02-01 |
| publisher | MDPI AG |
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| series | Sensors |
| spelling | doaj.art-45f14198c5144042804c80f386f6e1952025-02-25T13:47:37ZengMDPI AGSensors1424-82202025-02-01254113010.3390/s25041130An Autoregressive-Based Motor Current Signature Analysis Approach for Fault Diagnosis of Electric Motor-Driven MechanismsRoberto Diversi0Alice Lenzi1Nicolò Speciale2Matteo Barbieri3Department of Electrical, Electronic and Information Engineering, University of Bologna, Viale del Risorgimento 2, 40136 Bologna, ItalyDepartment of Electrical, Electronic and Information Engineering, University of Bologna, Viale del Risorgimento 2, 40136 Bologna, ItalyDepartment of Electrical, Electronic and Information Engineering, University of Bologna, Viale del Risorgimento 2, 40136 Bologna, ItalyDepartment of Electrical, Electronic and Information Engineering, University of Bologna, Viale del Risorgimento 2, 40136 Bologna, ItalyMaintenance strategies such as condition-based maintenance and predictive maintenance of machines have gained importance in industrial automation firms as key concepts in Industry 4.0. As a result, online condition monitoring of electromechanical systems has become a crucial task in many industrial applications. Motor current signature analysis (MCSA) is an interesting noninvasive alternative to vibration analysis for the condition monitoring and fault diagnosis of mechanical systems driven by electric motors. The MCSA approach is based on the premise that faults in the mechanical load driven by the motor manifest as changes in the motor’s current behavior. This paper presents a novel data-driven, MCSA-based CM approach that exploits autoregressive (AR) spectral estimation. A multiresolution analysis of the raw motor currents is first performed using the discrete wavelet transform with Daubechies filters, enabling the separation of noise, disturbances, and variable torque effects from the current signals. AR spectral estimation is then applied to selected wavelet details to extract relevant features for fault diagnosis. In particular, a reference AR power spectral density (PSD) is estimated using data collected under healthy conditions. The AR PSD is then continuously or periodically updated with new data frames and compared to the reference PSD through the Symmetric Itakura–Saito spectral distance (SISSD). The SISSD, which serves as the health indicator, has proven capable of detecting fault occurrences through changes in the AR spectrum. The proposed procedure is tested on real data from two different scenarios: (i) an experimental in-house setup where data are collected during the execution of electric cam motion tasks (imbalance faults are emulated); (ii) the Korea Advanced Institute of Science and Technology testbed, whose data set is publicly available (bearing faults are considered). The results demonstrate the effectiveness of the method in both fault detection and isolation. In particular, the proposed health indicator exhibits strong detection capabilities, as its values under fault conditions exceed those under healthy conditions by one order of magnitude.https://www.mdpi.com/1424-8220/25/4/1130condition monitoringfault diagnosiselectric motor-driven mechanismsmotor current signature analysisdata-driven methodsautoregressive modeling |
| spellingShingle | Roberto Diversi Alice Lenzi Nicolò Speciale Matteo Barbieri An Autoregressive-Based Motor Current Signature Analysis Approach for Fault Diagnosis of Electric Motor-Driven Mechanisms Sensors condition monitoring fault diagnosis electric motor-driven mechanisms motor current signature analysis data-driven methods autoregressive modeling |
| title | An Autoregressive-Based Motor Current Signature Analysis Approach for Fault Diagnosis of Electric Motor-Driven Mechanisms |
| title_full | An Autoregressive-Based Motor Current Signature Analysis Approach for Fault Diagnosis of Electric Motor-Driven Mechanisms |
| title_fullStr | An Autoregressive-Based Motor Current Signature Analysis Approach for Fault Diagnosis of Electric Motor-Driven Mechanisms |
| title_full_unstemmed | An Autoregressive-Based Motor Current Signature Analysis Approach for Fault Diagnosis of Electric Motor-Driven Mechanisms |
| title_short | An Autoregressive-Based Motor Current Signature Analysis Approach for Fault Diagnosis of Electric Motor-Driven Mechanisms |
| title_sort | autoregressive based motor current signature analysis approach for fault diagnosis of electric motor driven mechanisms |
| topic | condition monitoring fault diagnosis electric motor-driven mechanisms motor current signature analysis data-driven methods autoregressive modeling |
| url | https://www.mdpi.com/1424-8220/25/4/1130 |
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