| Bilateral synchronous motor drive is the typical structure of the high-speed CNC machining center of gantry moving gantry axis drive,it guarantees the synchronization of processing tension and the linear velocity.In the mechanical processing,control precision of gantry axis is so important that it directly impacts the machine precision of machining center and the quality of products,so reducing the synchronization error and increasing the efficiency of synchronization is the key to improve the performance of machine tool.Due to the asymmetric structure and the asymmetric stress of large moving parts such as spindle,beam and all kinds of uncertain disturbances,the height of the gantry framework can't always remain the same.The mechanical coupling generated by the inconsistency would reduce the synchronous feed precision,impair the processing quality,even destroy the drive components.In this thesis,pid-fuzzy control algorithm has been established by coupling control deviation under the fundamental of analyzing the PMSM and the model of uniaxial servo control system,which could increase the response speed of synchronizing shaft,and have the advantage of strong robustness and small synchronization error.The main research achievements are summarized as follows:1)The model of PMSM has been established by magnetic field oriented control principle under the fundamental of analyzing the PMSM.The vector control method id=0 has been utilized in this thesis.The theory model of stator three-phase current,speed and torque of PMSM has been established with the application of SVPWM technology.The simulation analysis of three important technique parameters has been carried out by MATLAB/Simulink.The simulation result shows that all the models is effective.2)The dynamic model of three closed-loop systems has been established by analyzing the current loop,speed loop and position loop of the uniaxial servo system.The current loop was combined with the PMSM mathematical model,the vector control strategy of id=0 and feed forward decoupling control method of design voltage.The simulations reveal that the impact of system parameter on forward decoupling control method of design voltage was small than that on ordinary current decoupling method.The forward decoupling control method has better loading capacity and anti-interference performance which could improve the current loop servo system dynamic performance effectively.The speed loop adopts PDFF control method.The simulations reveal that compared with ordinary PI control,the response speed of the output speed was faster,the stability was higher and the servo precision is also improved under PDFF control,which improved the dynamic and static performance of speed loop servo system.Position loop is controlled by the most simple and effective PID,the simulations reveal that the response speed of position loop is fast and non-overshoot.3)With combination of single axis model,biaxial synchronous control method in which deviation is regulated by fuzzy-pid control algorithm has been put forward under deviation coupling control mode.The simulations reveal that deviation coupling system which is adopted pid-fuzzy control algorithm has better synchronous control precision,stronger robustness and faster response speed.4)Mathematical modeling and structural analysis of milling-lathe machining center(HTM200)have been conducted in this thesis.PID-fuzzy control algorithm under deviation coupling control mode has been applied in milling-lathe machining center(HTM200).The detection and analysis of Y axis servo control accuracy with laser interferometer shows that Y axis servo control accuracy can reach 0.01mm,which is enough for the machining requirements. |
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