Design And Experiment Of Automatic Surfacing Repair Control System For Turbine Guide Vane

Hydroelectric power generation has become one of the main sources of electricity in China.Due to the high sediment content in rivers in Xinjiang region,the movable guide vane of hydraulic turbine suffers from serious wear during hydroelectric power generation,and the traditional method of repairing worn guide vane by manual overlay welding is labor-intensive,costly,inefficient and difficult to guarantee quality.In view of the above problems,the design of a hydraulic turbine guide vane automatic overlay welding repair control system is proposed.After test verification,the system has strong practicality and can meet the requirements of overlay welding repair of worn hydraulic turbine guide vane.The main research work is as follows:（1）Overall scheme design of hydraulic turbine guide vane automatic overlay repair control system.The working principle of hydraulic turbine guide vane automatic overlay repair device and the structural composition of the whole system are analyzed and studied,the overlay repair paths of different wear positions of the guide vane are planned,and the overall scheme of the control system is completed according to the analysis of the functional requirements of the control system,the control mode of PLC controller plus touch screen is determined,and the control scheme of semi-closed loop control system is selected.（2）The trajectory control of the welding torch for guide lobe overlay repair.For the spatial characteristics of different wear parts of the guide vane,the mathematical models of plane,cylindrical surface and semi-cone surface were established,and the interpolation trajectory of the torch end movement during overlay welding was studied by using the principle of spatial analytic geometry,and the overlay welding repair process for each wear part of the guide vane was developed.（3）Based on the control principle of PLC and touch screen,the software and hardware design of hydraulic turbine guide vane automatic overlay repair control system is completed.Firstly,the hardware circuit of hydraulic turbine guide vane automatic overlay repair control system is designed,and the hardware models of lower PLC controller,upper touch screen（HMI）,servo motor and servo driver are determined;then the software is designed as a whole,mainly including the touch screen human-machine interface,upper touch screen interpolation algorithm program and lower PLC ladder diagram;finally,the whole control system is installed and debugged to verify the feasibility and stability of the control system.Finally,the whole control system is installed and debugged to verify the feasibility and stability of the control system.（4）The welding test of hydraulic turbine guide vane automatic overlay repair control system was completed.The three-factor five-level response surface test was designed to obtain the regression model of welding process parameters and weld seam forming size,and the analysis of variance was conducted to optimize the optimal welding process parameters and test verification according to the needs of wear guide vane overlay repair;then the weld lap test was conducted to determine the optimal lap interval for overlay welding through the evaluation index of the extreme difference value;the optimal overlay welding process parameters were determined to be overlay welding The optimal overlay process parameters were determined to be overlay current of 164 A,overlay voltage of 25.4 V,overlay speed of 6.2 mm·s^-1,and weld interval of4 mm.Finally,an overlay repair test was conducted on the worn guide vane and the overlay layer was non-destructively inspected.The test shows that the hydraulic turbine guide vane automatic overlay repair control system designed in this thesis is feasible and can meet the requirements of overlay repair of worn guide vane in Hongshanzui power plant.