Research And Application Of Lifting Load Measurement Technology Based On Motor Torque Current

The vertical shaft construction hoist is the only way to connect the underground construction area and the ground,which is responsible for important tasks such as lifting materials,transporting equipment,and lifting personnel.The uncertainty of lifting load will bring serious safety risks to the operation of the hoist,and threaten the smooth progress of the whole construction process.At present,the variable frequency vector control is rapidly promoted and applied to the shaft construction hoist with asynchronous motor as the power source.On this basis,this paper studies the lifting load measurement technology based on torque current,and applies this method to the electrical control system of the vertical shaft construction hoist to ensure the safe operation of the system.Firstly,the mathematical model of AC asynchronous motor is established,the relationship between torque current and electromagnetic torque is analyzed under frequency conversion vector control,then the mechanical moving parts of the hoist are analyzed in dynamics and kinematics,and the relationship between load torque and lifting load under different operation conditions is studied.Then,the electromechanical coupling model of the hoist for shaft construction is established.According to the model,the relationship between torque current and lifting load is obtained.Finally,the simulation model is built by MATLAB\SIMULINK,and the change of torque current in each operation stage in a single lifting and lowering cycle under a specific lifting load is simulated and analyzed,which verifies the feasibility of measuring lifting load through torque current.Secondly,there are two kinds of lifting load measurement methods proposed.The first method is based on the electromechanical coupling model,and the lifting load can be directly solved by the torque current through the transformation of mathematical relationships.The other method is based on the machine learning,the relationship model of torque current and lifting load is constructed by Support Vector Machine(SVM),so that the lifting load can be fitted by torque current.Both methods are simulated and analyzed here,and the measurement accuracy of the two methods is verified.In addition,in view of the problems such as the fluctuation,impact and jamming of the hoisting load during the operation of the vertical shaft construction hoist,based on the above two methods,the fault load is further discussed,and the identification effect of the two methods for different fault disturbance load is analyzed,which provides a theoretical basis for fault judgment.Finally,the two load measurement methods are compared,and the results show that both methods can meet the industrial demand,the paper combines the two methods.Finally,on the basis of practical application,based on the requirements of the measurement system,the overall hardware architecture of the measurement system are designed,including MCU,signal acquisition,E2 PROM storage,bus interface and power supply,and the corresponding software program of various functions are compiled.The PC is designed with LabVIEW,and the PSO-LSSVM is run on the LabVIEW by the mixed programming of MATLAB and LabVIEW.The combination of two load measurement methods is successfully implemented in the PC.Finally,the platform of the system is built and debugged,and the debugging results can meet the design requirements of the system.There are 72 figures,15 tables and 84 references in this thesis.