Research On Health Monitoring For The Scraper-chain System Of The Heavy Scraper Conveyor

As the hub equipment of modern mechanized coal mining face,the heavy scraper conveyor undertakes the important tasks,such as transporting coal,providing walking track for shearer and furnishing the push support for hydraulic support.Its safe operation affects the transportation safety and production efficiency of modern coal mines to a great extent.As the key transmission and load-bearing parts of the scraper conveyor,the scraper-chain system(multiple joint chains,multiple scraper blades and multiple middle chutes)should not only overcome the time-varying load resistance of coal,but also bear great static and impact loads.Chain breaking,chain jamming and other faults inevitably occur,which might damage equipment and hurt downhole workers in serious cases.Therefore,it is of great significance to carry out the research on the theory and method of online monitoring for the health condition of the scraper-chain system to ensure the safe and stable operation of the heavy scraper conveyor.This research is supported by the key project of NSFC Shanxi coal-based low carbon joint fund “Research on intelligent drive system of heavy scraper conveyor”(Project No.U1510205)and the innovation team development plan project of the ministry of education “Reliability of large electromechanical equipment in mines”(Project No.IRT＿16R68).Taking the heavy scraper conveyor as the research object,the health monitoring for the scraper-chain system of the heavy scraper conveyor is carried out by combining theoretical research,simulation analysis and experimental testing.The main contents are as follows:Firstly,according to the structure and working principle of scraper conveyor,the distribution law of force and tension of chain in the scraper-chain system is analyzed and the difficulty in monitoring the chain tension of scraper conveyor in operation is expounded;Then combined with the actual operation condition of scraper conveyor,the chain fault,scraper fault and other faults of the scraper-chain system are discussed and analyzed in detail;Considering the change of the pose morphology when the middle chute is pushed and the change characteristics of the scraper pose morphology and chain tension when the chain is broken,the condition monitoring principle of the scraper-chain system is explained,and then a health monitoring method of the scraper-chain system based on the perception of the middle chute position and pose,scraper posture and chain tension is proposed.Secondly,a study on the UWB monitoring network technology of the scraper-chain system is conducted.Considering the complex working environment of fully mechanized mining face,the overall architecture of UWB monitoring network of the scraper-chain system is designed,and the deployment scheme and use of various nodes in monitoring network are put forward;Aiming at the mobility of fully mechanized mining face and the changes of base station node position,the self-positioning technology of base station nodes in monitoring network is compared and analyzed with different algorithms,and the self-positioning technology of base station node based on modified Newton iteration method is proposed;According to the characteristics of linear monitoring area of fully mechanized mining face,two kinds of layout strategies of transmission nodes in monitoring network are proposed,and the timeliness of transmission network is verified by OMNe T++ simulation software,which can meet the parameter requirements of data transmission delay of monitoring network for the scraper-chain system.Then,the research on the pose recognition method of the middle chute and scraper in the scraper-chain system is studied.In order to realize the position and attitude recognition of the scraper-chain system,the ranging principle and localization algorithm based on UWB are analyzed;In order to monitor and identify the pose morphology of the middle chute,a pose morphology model of the middle chute is established and a method to characterize the straightness of the middle chute is proposed,and UWB technology is used to identify the shape of the middle chute,and the performance of pose recognition of the middle chute is verified by simulation;In order to obtain the position and pose information of the scraper during movement,the position and pose model of the scraper is established,and the scraper pose recognition technology based on ranging constraint selection method(RCSM)and extended Kalman Filter(EKF)is proposed,which could effectively improve the recognition accuracy of the scraper pose and realize dynamic monitoring for the position and pose of the scraper.Then the performance of position and pose recognition method of the scraper is also verified by simulation.Finally,the health monitoring experiment of the scraper-chain system is carried out.Comprehensively considering the state characteristic changes and monitoring methods of the scraper-chain system,the health state monitoring process of the scraper-chain system is introduced,and the specific monitoring process of the middle chute,scraper pose and chain tension of the scraper conveyor is described in detail;In order to verify the monitoring method of the scraper-chain system proposed in this dissertation and obtain the corresponding monitoring data,the experiment test platforms are designed and built to monitor the morphology of the middle chute,the tension of the scraper chain and the posture of the scraper;By analyzing the experimental monitoring data,the results show that:(1)In the monitoring experiment for the morphology of the middle chute,the proposed method based on UWB can accurately detect the straightness of the middle chute,and the maximum straightness deviation measured by the experiment is 2.34 cm,and at the same time it can also detect the shape trajectory curve of the bending segment when the middle chute is pushed.(2)In the tension monitoring experiment for the scraper chain,it is found that the strain of the chain shows a certain periodic fluctuation law during normal operation and the strain fluctuation at the symmetric position of the two chains is highly consistent,with the same fluctuation period and little difference in amplitude.At this time,the relative tension difference of the two chains(35)F is less than 1 in most cases.However,when the chain breakage occurs,the relative tension difference(35)F between the two chains will continue to be equal to 1 for several sampling periods.(3)In the posture monitoring experiment for the scraper,the pose tracking and identification method for the scraper based on the RCSM and EKF proposed in this dissertation can monitor the posture of the scraper in real time during the process of running,and also can monitor the offset value at both ends of the scraper blade to judge indirectly whether the chain of the scraper-chain system has broken or not,which can determine the health state of the scraper-chain system.There are 85 figures,8 tables and 130 references in the dissertation.