Design Of Optimized Integrated Welding Machine Controlled By PLC And Industrial Robot

Industrial centrifugal fans find their applications commonly in air conveyor systems,furnaces,cooling and drying systems.The process of manufacturing these fans involves welding,which is a very hectic,delicate and dangerous process,and generally needs highly skilled personnel.Furthermore,welding of centrifugal fan is very difficult due to the complex structure associated with it.There is need for wide range variation of welding posture in order to access the hollow spaces between the blades.This makes precision and consistency very challenging,hence high risk of bad weld quality.To solve these issues,we propose improved efficient automatic welding machine that integrate several electromechanical components to produce an optimized welding operation for the centrifugal fan.The following contents were studied.(1)An integrated welding system design is put forward with model-based kinematic control involving 6-axis industrial robot,2-axis positioner,HMI,PLC,welding power supply unit and a welding gun.Time-optimal coordinated motion is generated based on individual joints constraints.(2)Mathematical models based on the robot and positioner dimensions,homogeneous transforms,D-H parameters and time minimization techniques are developed to describe robot and positioner kinematics and motion coordination.The formulation proposed is independent of system mechanics.Matlab simulations verify models accuracy by generating "stick-figure" plot of robot and positioner in their 3D workspace,and kinematics analysis validates accuracy of trajectories generation.(3)CAD designed components are used in roboguide simulation with high resolution graphics to analyze the feasibility and dynamics of industrial fan welding operation,and for prediction of any conceptual malfunction before any physical realization,hence saving cost and material.The simulation and experimental results illustrate the coordination performance of proposed conrol algorithm and time optimal operation for accurate results.(4)The welding robot system control scheme is realized based on PLC controller and HMI designs.PLC ladder program integrates the system components with high flexibility which helps control various actuators and sensors at high processing speed while performing smooth control.A parameter optimization method is proposed and results demonstrate flexibility,reliability,and efficient control strategy.