| The feed system is the basic control unit and core functional part of the numerical control equipment.With the rapid development of high-end equipment manufacturing,the requirements for performance and accuracy of feed system are getting higher and higher.Under this background,the dual-driving feed system with strong load capacity,large system rigidity,and good dynamic performance has received more and more attention.It has been gradually applied to high-speed,high-precision,heavy-load CNC equipment.In this paper,a gantry mobile feed system is taken as the research object,which is equipped with a dual-driving synchronous feed unit.The purpose of this research is to improve the tracking accuracy and synchronization accuracy of the dual-driving feed system.The contents of the research are as follows:(1)Firstly,the technical advantages and driving principle of the gantry mobile dual-driving feed system are analyzed in this paper.Then a model of servo control system is established based on the built mathematical model of the synchronous driving motor and the three-loop control structure.Considering the coupling relationship between the driving shafts due to the mechanical connection,the model of mechanical transmission part is established as well.Finally,the electromechanical coupling model of the dual-driving feed system is gotten.(2)Considering the effect of friction on the feed performance,a dual-driving synchronization control strategy is designed in this paper.The relationship between the position of the moving part on the gantry beam and friction on the driving shafts is analyzed,and a friction model considering the position of moving part on the gantry beam is established by the method of Stribeck friction model and Newton's interpolation.Then combining the friction compensation with cross-coupling synchronous control structure,the cross-coupling synchronization control strategy based on friction compensation is proposed.And the effectiveness of the strategy is simulated and verified.(3)The overall structure of the gantry mobile dual-driving feed platform is introduced in this paper.The fully closed-loop control system of the experimental platform is realized by selecting and integrating the key hardware of the control system.Based on the principle of Twincat motion control,the Visual Studio development platform is adopted to develop a piece of control software to achieve motion control of the feed system.(4)The synchronous control experiments of the gantry mobile dual-driving feed system are carried out in this paper.The synchronous control experiments can be divided into two parts: comparative experiments of master-slave synchronous control and cross-coupling synchronous control,comparative experiments of synchronous control with and without friction compensation.By analyzing the changes of the tracking error and synchronization error of the dual-driving feed system,the effectiveness of the proposed cross-coupling synchronization control strategy based on friction compensation is proved. |
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