The Research On Self Powered Chain Tension Monitoring System Of Mine Scraper Conveyor

Scraper conveyor is an important mechanized coal mining equipment for fully mechanized mining face.The efficient and stable operation of the scraper conveyor can effectively ensure the coal production benefits of coal mines.The circular chain of the scraper conveyor is an important load-bearing component,and the stability of the scraper chain is of great significance to safe mining.Because the scraper chain reciprocates for a long time under a specific tension,and is affected by moisture,impact and vibration,its failure rate is high,and it is prone to broken chain,chain jam and floating chain failure.The monitoring of chain tension is an important measure to ensure the safe operation of the scraper conveyor.Generally,a sensor system is equipped on the scraper to detect the tension state of the chain,which can further predict the failure of the scraper chain,chain jam,etc.,analyze the scraper straightening quality and predict the chain life.At present,the tension detection system is battery-powered,and the device needs to be disassembled regularly to replace the battery,which cannot guarantee the long-term continuous operation of the tension detection system.To this end,this dissertation proposes a self-powered chain tension detection system,the main research content is as followsFirst,the overall design of the chain tension wireless monitoring system is carried out,and the whole system is divided into parts,which are the tension data acquisition device,the single-chip microcomputer,the wireless transmission device and the self-powered device.In view of the harsh electromagnetic environment of the scraper conveyor,especially the weakening effect of mine water on electromagnetic waves,the weakening effect of mine water and materials on electromagnetic waves in various frequency bands is theoretically analyzed.Combining the characteristics of electromagnetic waves in various frequency bands,433 MHz electromagnetic waves are finally selected as the working frequency band.The hardware part of each device is designed,and the energy-saving scheme of the circuit is designed based on the triggering of the self-powered device and the wake-up of electromagnetic waves.The scraper was modified,and the installation method of each device was introduced.For the self-powered device,two schemes are proposed,one is a linear generator,and the other is a vibration energy harvesting device.Both schemes are studied.Secondly,a theoretical analysis of the linear motor is carried out.According to the size and operating characteristics of the scraper,the size of the linear generator is determined in the limited available space.According to the structure of the scraper,the U-shaped structure of the generator mover and the structure parameters of the stator are determined.Using Maxwell software,a finite element simulation model of the generator was established,and the influence of the air gap and synchronous speed on the performance of the generator was analyzed;the resonance circuit was designed to improve the energy utilization efficiency;the expected power value was derived according to the distribution law of the air gap.At the same time,a vibration energy harvester was designed with the movement of the scraper as the energy source.A negative damping vibration system based on frictional selfexcited oscillation is constructed,which converts the linear motion of the scraper into the reciprocating vibration of the mass block,and then drives the generator to generate electricity to achieve energy extraction.The dynamic modeling and theoretical analysis of the vibration system are carried out,the differential equations of the vibration system are established,and the conditions for the stable vibration of the system are analyzed.Simulink software is used to simulate and analyze the system vibration under different working conditions.Finally,an electromagnetic wave wireless transmission test was carried out to test the transmission distance of 433 MHz in a mixed environment of pure water and coal gangue water.The average power consumption of the chain tension detection system is 60 m W.A prototype of a permanent magnet linear generator was processed and analyzed by experiments.The average power generation of the final prototype is 546 m W.And a test device for the vibration energy harvesting device was built,and the results showed that the power of the vibration energy harvesting device was 426 m W.The two schemes basically meet the needs of the system.