Industrial Applications of Cable Diagnostics and Monitoring Cables via Time–Frequency Domain Reflectometry

Current Only-Based Fault Diagnosis Method for Industrial Robot Control Cables

“…Until now, the efficiency of reflectometry-based methods for cable diagnostics has been demonstrated [8][9][10][11][12][13][14]. In particular, time-frequency domain reflectometry (TFDR) [12,13] proves the robustness of fault diagnosis in a variety of conditions because it utilizes information in time and frequency domains.…”

“…Until now, the efficiency of reflectometry-based methods for cable diagnostics has been demonstrated [8][9][10][11][12][13][14]. In particular, time-frequency domain reflectometry (TFDR) [12,13] proves the robustness of fault diagnosis in a variety of conditions because it utilizes information in time and frequency domains. Although these methods diagnose hard faults effectively owing to its huge reflection, their diagnostic accuracy for small anomalies is not always effective because of the physical difficulties, such as the ambiguous response of the incident signals [7].…”

“…In addition, because automated machines in the factory floor are not easily accessible, additional equipment is not preferable when conducting diagnosis. Therefore, all the diagnosis methods that require additional equipment [8][9][10][11][12][13][14][15] are not preferable. In addition, the automation machines in manufacturing lines work round the clock; therefore, using an offline diagnostic approach with no online diagnostic capability is not preferable.…”

“…(1) Only three-phase currents are used. Therefore, additional sensors, signal generators, and signal inducing devices are not required, making the method cost efficient, whereas the other methods [8][9][10][11][12][13][14] need additional devices to generate a reference signal and to inject the reference signal into target cables. For example, an arbitrary waveform generator is used to create the designed reference signal in [8][9][10][12][13][14].…”

“…In [11], a network analyzer is used to inject sinusoidal waves into the target cable and to measure the reflected waveforms. For signal injection, an inductive coupling device is used in [9], whereas others [8,10,[12][13][14] utilize three-way connectors, such as T-connectors, and directional bridges. (2) No manual feature extraction with prior knowledge and mathematical values of cable parameters is required, whereas reflectometry based methods need physical cable parameters, such as the information of cable length, to design an incident signal by adjusting signal bandwidth, center frequency, and time duration.…”