Research On The Method Of Pump-valve Coordinated Control For The Bending And Testing Machine Based On The Predictive Control

With the development of modern manufacturing technology,the welding structure and its composition of materials are becoming more and more complicated and diversified,especially the application of unequal thickness of welded joints and different materials of welded joints are using more and more widely.Commonly used detection method is the method of three-point bending and testing.The method uses two points as the support points of the welding parts,and the third point that the weld point is aligned with the bending axis.In the process of squeezing the weld,it is easy to produce the phenomenon of displacement,resulting in the bending axis can not all act on the weld and affecting the test result.If using such welding parts blindly may lead to failure fracture problems in practical application.So once encounter the situation in the test,the experimenter must choose material and continue to test again.Not only extending the test cycle,but also delaying the progress and causing the waste of material and artificial.So it is urgent to develop the bending and testing machine for unequal thickness of welded joints and different materials of welded joints.The main contents of this paper are as follows:(1)The application as well as advantages and disadvantages of pump control system and valve control system are analyzed.And the research status of pump-valve coordinated control and predictive control algorithm is introduced.The paper proposes a relatively rare of bending and testing machine with two rolls.According to the functional characteristics of the roller bending and testing machine,the working mode of pump-valve coordinated control was determined.(2)According to the working characteristics of roller bending and testing machine,the hydraulic system is simplified.The transfer function of the pump control hydraulic cylinder is established.The pump control part adopts the predictive control algorithm to obtain the control quantity of the variable pump.The valve control part uses the optimization control algorithm of electromagnetic reversing valve to obtain the control signal of three four-way electromagnetic valve.(3)The model of the pump-valve coordinated control hydraulic cylinder is completed by AMESim.The PID algorithm and optimal control algorithm for electromagnetic valve and the predictive control algorithm are designed in Matlab.After the joint simulation,the expected control effect is obtained,which proves the effectiveness of the predictive control algorithm in the process of pump-valve coordinated control.(4)The experimental system of pump-valve coordinated control is established by using the IPC as the upper computer and the motion controller as the lower computer.The algorithm is implemented to the roller bending and testing machine by the mixed programming of VB.net and Matlab,which improves the control performance of the system effectively and achieve a good control effect.