Design Of The Control System Of A4DOF Cartesian Welding Robot

With the rapid development of economy in recent years, industrial robots have beenwidely applied in various fields, especially the welding field due to its harsh environment.However, currently used welding robots are mainly general industrial robots for complicatedwelding tasks. And for the single welding task, it will cause the waste of function. In addition,since the price of general industrial robots is pretty high, this increases the cost of production.In order to resolve this practical problem and meet the high demand of the enterprise, thisthesis has designed the control system of a4DOF cartesian welding robot.At first, a comparison of the DC servo system and AC servo system is made, as well asthe centralized control mode and distribution control mode. The overall scheme for thecontrol system is designed according to the industrial use of the4DOF cartesian weldingrobot. And then type selection and checking of the AC servo motor and linear module areconducted according to the overall scheme.Second, the mathematical model for the permanent-magnet synchronous motor in d-qcoordinates is built and the current feedback decoupling is conducted by the equation of state.On the basis of the decouple motor model, the regulators of the current loop, speed loop andposition loop of welding robots in the Z axis AC servo system are designed with the controllerengineering design method. Also, the simulation model of the Z axis AC servo control systemin Matlab/simulink is set up to achieve the step response simulation at different speeds andgiven positions. Besides, the simulation software of G code track is edited by applying MFC,enabling the operator to test the correctness of the generated trajectory before using the Gcode documents.At last, the control system of4DOF cartesian welding robot is built. The method ofimproving the anti-interference performance of the control system is explored in physicalconnections. Besides, a large amount of material welding experiments is carried out with theexperimental prototype to test the stability and positioning accuracy of the control system.