Broad zero-shot diagnosis for rotating machinery with untrained compound faults

Compound fault diagnosis of rotating machinery is of great significance for the operational reliability and security of manufacturing equipment. Since the possible compound fault types increase exponentially, the compound faults appear in the test phase may not be covered during training, posing great challenge for machine health monitoring. Recently, several methods attempt to construct the semantic space for untrained compound faults. However, the semantic space suffers from the low-fidelity to identify the untrained compound faults. Besides, most of these methods only focus on untrained compound faults, ignoring more common single faults in the test set. To address these issues, a novel broad zero-shot diagnosis method (BZSD) is proposed to identify both single faults and untrained compound faults. Firstly, the multiresolution permutation entropy is presented to identify single faults and preliminarily screen out the untrained compound faults, which can prevent the compound fault from being biased towards the trained single fault. Then, a high-fidelity semantic space is constructed to classify the pre-screened compound faults. The proposed fault semantics are close to the ground truth semantics, which is conducive to improving diagnostic accuracy. The experiments demonstrate the effectiveness and superiority of the BZSD for rotating machinery with untrained compound faults.