As a wear particle detection technology for machinery, electrostatic monitoring has broad application prospects However, there is currently a lack of a comprehensive method for achieving precise wear particle detection through electrostatic signals. This study proposes a wear particle detection method based on coaxial array electrostatic probes and a VMD-SR-DTW algorithm model. Firstly, a joint signal processing model is constructed using Variational Mode Decomposition (VMD) and Sparse Representation (SR) to reduce noise interference and enhance the signals triggered by wear particles. Furthermore, an algorithm model based on sliding windows and Dynamic Time Warping (DTW) is developed by utilizing the multi-channel signals from the coaxial array electrostatic sensor. The overall algorithm flow is analyzed in detail. Simulations and experiments are conducted to validate the effectiveness of the proposed method. The results demonstrate that the method effectively detects the signal pulses triggered by wear particles and provides a reliable approach for the engineering application of online monitoring.

Heavy equipment gear transmission system require monitoring of wear particles in lubricating oil to assess the degree of wear and predict failure. Compared to the traditional detection method, electrostatic sensor is an innovative online sensor for wear particle monitoring due to its high sensitivity and strong capability of early fault warning. This study presents a new spiral-shaped probe electrostatic sensor (S.P.E.S) and derives an analytical mathematical model of point charges on a spiral-shaped probe based on the physical model. To obtain a deeper understanding of the spiral-shaped probe, a finite element model was developed by using COMSOL software to explore the sensing characteristics and spatial static sensitivity of the spiral probe. Furthermore, experimental studies were conducted to investigate the dynamic sensitivity. The findings indicate that the sensitivity distribution of SPES is asymmetric due to the asymmetric structure of the probe. The simulation analysis and experimental provide a scientific basis for the design of spiral-probe sensor.

The current depletion of high-quality coal seams, hard coal mining had become the norm, while the traditional mechanical cutting methods were inefficient. A multi-impact cutting technology was proposed, which was to design a hydraulic system inside the drum. A hydraulic control system was formed by the hydraulic impact pick driver set by the ranging arm and the cutting motor to realize the reciprocating impact movement of multiple picks. The impact of picks was used to make the coal synchronously pre-crack, thereby reducing the difficulty of hard seam mining. In this paper, by analyzing the working process of the multi-impact drum, the corresponding mechanical model was established and the overall research plan was determined. A simplified drum model was established using CATIA, a coal model was established in EDEM based on the physical and mechanical properties of hard coal, and a simulation experiment composed of the cutting drum and coal model was based on orthogonality. The test method explored the working performance of the multi-impact drum under the action of multiple factors in cutting different media, using different impact frequencies and different drum speeds. The results showed that the coal breaking rate was used as the evaluation index, the order of the influencing factors was: A>C>B (coal hardness> drum speed> impact frequency), and the optimal plan combination was A2B1C3 (coal wall hardness was f5, impact frequency was 4Hz, drum speed was 40r·min -1 ); taking cutting specific energy consumption as the evaluation index, the order of influencing factors was: C>A>B (drum speed>coal hardness>impact frequency), the optimal plan combination was A2B1C3 (coal wall hardness was f5, impact frequency was 4Hz, drum speed was 40r·min -1 ). The matrix analysis method was further introduced to calculate that the order of the influence of each factor on the index value of the orthogonal test was C>A>B (drum speed>coal hardness>impact frequency), when the coal hardness was f5, the impact frequency was 4Hz, and the drum speed was 40r·min -1 , the working performance of the multiimpact cutting drum was the best. Under the same working conditions (coal hardness was f5, drum speed was 40r·min -1 ), a comparative simulation experiment of the traditional drum was carried out. Compared with the simulation results, the coal falling amount of the multi-impact drum was about 24.86% higher than that of the traditional drum, and the cutting specific energy consumption of the multi-impact drum was 0.7423kW·h/m 3 , which was about 21.67% lower than that of the traditional drum. Finally, a simplified multi-impact drum industrial cutting test was carried out. The test results showed that the cutting resistance of the multi-impact drum was about 17.22% lower than when there was no impact. Considering that the simplified multi-impact cutting drum had a reduced impact pre-cracking effect on the coal, it can be considered that the results of the industrial test and the discrete element simulation test were still relatively consistent. The multi-impact cutting drum had good working performance under hard coal conditions.