According to the nonlinearity, non-stationarity and multi-component coupling characteristics of reciprocating compressor vibration signals, a fault diagnosis method of a reciprocating compressor valve based on modified multiscale entropy (MMSE) and global distance evaluation (GDE) is proposed. First, the variational mode decomposition (VMD) method with superior anti-interference performance was utilized to analyse the strong non-stationarity vibration signals for all fault states. The modified multiscale entropy (MMSE) method provided for movingaverage procedures by replacing mean-average coarse-grained procedures was developed for the vibration signals after de-noising, and then the GDE method of overall parameter selection was introduced to evaluate the extracted MMSE and to select the optimal sensitivity scale feature. Finally, a binary tree of support vector machine (BTSVM) was selected as the classifier to identify the reciprocating compressor valve fault type. By analysing the experimental data, it can be shown that the method can effectively identify the fault type of the reciprocating compressor valve. Keywords: fault diagnosis, reciprocating compressor valve, modified multiscale entropy, global distance evaluation, binary tree of support vector machine Highlights • An integrated fault feature extraction method of a reciprocating compressor valve based on the VMD-MMSE and GDE is proposed. • A consistent number K of band-limited intrinsic mode functions (BLIMFs) were selected based on a novel criterion for all fault states • The MMSE method provided for the moving-average procedure by replacing mean-average coarse-grained procedure was developed for the vibration signals, GDE was introduced to refine the eigenvectors for higher recognition efficiency and accuracy. • The effectiveness of this method is verified by the recognition results of BTSVM in comparison to other feature extraction methods.

According to operation requirement for overhead transmission lines inspection, designing and manufacturing the small UAV airborne pod system structure which has two axis three framework with spring damping system , assembling into the UAV for ultrahigh pressure overhead transmission lines inspection test. The test data showed that the accuracy of the small UAV airborne pod system stabilization met the requirement of transmission line inspection. The operation situation of transmission line and the growth situation of the trees around the transmission lines could be clearly observed. In order to quickly, effectively discover and eliminate ultrahigh pressure transmission line fault by providing clear image information, which had obvious superiority with the environment of high altitude and low temperature. The rationality of theoretical analysis and the practicability of transmission lines inspection for small UAV airborne pod system were verified.