Research On Optimization Of Tractor Key Detection Technology And Rapid Assembly Quality Test Technology

Agricultural machinery equipment is one of the "Top Ten" key areas determined by "Made in China 2025".The development of agricultural equipment to automation,informatization and intelligence has become an inevitable trend.As an important support for the development of high-end agricultural machinery and equipment,the application of intelligent verification key technology can not only improve the detection efficiency,but also is of great significance for improving the overall level and competitiveness of agricultural machinery and equipment in China.As one of the important equipment of agricultural mechanization,the assembly quality of tractor determines the stability,safety and reliability of the whole machine.The final inspection of assembly quality is an important link to ensure the performance of tractor.Although the domestic and foreign tractor assembly workshops have designed and implemented the detection content based on function and supplemented by performance for the final inspection link.However,there are differences in the structural characteristics,yield and quality requirements of tractors,which leads to the lack of effectiveness and real-time performance of on-line detection of the assembly quality.Therefore,it is urgent to construct tractor quality detection methods and technologies to provide scientific and technological support for the final inspection of tractors.Through the in-depth study of the fault characteristics,the detection direction is clarified for the assembly quality of the tractor.The fault characteristics study analyzes the fault type,mechanism,fault data and fault detection line of the tractor.The cause analysis of tractor detection failure was carried out,mainly considering assembly failure,assembly failure and assembly equipment,assembly method,assembly measurement and assembly environment.The fault symptoms of tractor engine,electrical appliance and chassis mechanism are studied,and the fault types,causes and locations are analyzed,which provides a basis for the improvement and optimization of fault detection methods.The tractor fault data were collected and counted,and the frequency and type of each fault were analyzed,which provided a clear direction for the research and development of the tractor quality inspection line.The minimum steering circle radius detection of tractor is an important means to evaluate the assembly quality of tractor steering system.The conventional steering circle radius detection method is dynamic detection,but the dynamic detection takes a long time and cannot meet the detection beat.Aiming at the existing problems,a laser non-contact measurement method and graphic analysis technology are proposed to detect the maximum geometric rotation angle of the tractor steering wheel,and realize the static indirect measurement of the minimum steering circle radius of the tractor.An on-line detection system for the minimum turning radius of tractors is developed.In order to reduce the detection space occupation,the minimum steering circle radius detection system is optimized.The minimum steering circle detection methods based on laser displacement sensor and binocular camera are proposed respectively,and the test algorithm is improved.The detection of tractor hydraulic suspension device can effectively evaluate the reliability of the assembly quality of the lifting mechanism.Conventional detection methods need to dig pits.In order to avoid destroying the test site,a ground hydraulic suspension test bench was developed.Because the connecting rod of the test bench can not be widely applied to various types of tractors,the standard loading rod is designed and the static analysis is carried out.The simulation results show that the designed standard loading rod can meet the maximum lifting force requirement.Aiming at the problem that the tractor hydraulic suspension device cannot be automatically hooked,an on-line automatic detection system for tractor hydraulic suspension device is developed,and the transient structure simulation analysis.Based on the vibration characteristics,the theory and method of rapid evaluation of assembly quality are studied,and the evaluation method of tractor assembly quality based on vibration intensity is proposed.Based on MEMS,a wireless three-axis vibration detection system was developed.The vibration velocity signal of the tractor body was measured,and the threshold value of the vibration velocity statistics was compared.According to the vibration intensity value,the fault hidden danger level was determined.According to the symmetry of the tractor structure,the vibration characteristics of the symmetrical structure are analyzed.Based on the vibration symmetry,it is speculated whether there is abnormal vibration in the working state of the tractor,and then the defects of the parts are judged.The tractor assembly quality state detection and diagnosis software is developed.The vibration diagnosis system can test the vibration intensity and symmetry of the symmetrical position,and diagnose the running state of the tractor.Based on the virtual material method,the influence of the connection tightness of the tractor on the vibration value is analyzed.The modal analysis of the tractor model is carried out by using the NX Nastran solver,and the different tightness states of the bolt connection of the tractor are simulated by changing the virtual material parameters.The relationship between looseness and vibration value at the joint of assembly structure was studied by bolt-flange structure.The optimization of tractor final inspection technology is studied in this paper.The static detection method of tractor minimum steering circle is used to replace the dynamic detection.The assembly quality detection method of tractor hydraulic suspension is analyzed,and the automatic detection system of tractor hydraulic suspension assembly quality is developed.The theory and method of rapid evaluation of assembly quality based on vibration characteristics are proposed,and the structure and vibration characteristics of the tractor are studied.A tractor assembly quality fault detection system suitable for the production line is developed.The modal simulation of the looseness model of the tractor assembly structure is carried out by using the virtual material method,which provides theoretical support for the final inspection of the tractor assembly quality.