| In recent years, linear motor has a number of advantages such as its simple structure, high positioning accuracy, and no intermediate transmission device. So in a variety of linear motion occasions, the linear motor is being used increasingly. Many times, in the process of machinery, it is need to be coordinated among multiple motors to cooperate to complete a project. Also the cooperation of multiple linear motors also improves the efficiency of industrial processes. Therefore, more and more people begin to study the cooperative control problem of the multiple linear motors. However, the structure of the linear motor is rather special. It has no intermediate conversion structure, external disturbance direct acting on the linear motor mover. On the other hand, there are cross coupling effect among multiple motors. It will influence the synchronous control. At the same time, it will reduce the processing quality and production accuracy. So it has important practical significance to improve the capacity of the multi-linear motors servo control system and reduce the synchronous control error among multiple linear motors.The main object of this study is dual PMSLM cooperative control system with an H-shaped structure (such as laser engraving machines, gantry-moving milling machines). In the first place, the article describes the problems between dual-linear motors synchronous control. Then this paper proposed the methods to solve these problems. Currently, there are many ways to improve control accuracy and keep the speed synchronization between dual PMSLM which generally includes the following aspects:optimizing the structure parameters of PMSLM; developed a new type of permanent magnet materials; improving the existing control algorithm or research new control algorithms and so on. This article goes about improving the control algorithm. There are two main problems on dual PMSLM synchronous control:the first one is how to realize the follow performance and disturbance resistance optimal at the same time for the single linear motor. Another one is how to realize position and speed synchronization control about the dual PMSLM.First of all, single PMSLM servo control system performance will directly determine the synchronization accuracy of dual PMSLM. However the traditional PID control algorithm can not balance both system tracking ability and anti-disturbance. A two degree of freedom PID control algorithm is used in this paper. Also we list several typical structure of the 2DOF PID controllers. The 2DOF control system with the setting value of feed-forward type has fewer parameters so that it is relatively easy to achieve. So we use this control algorithm in this paper. At the same time, we designed a controller based on the setting value of feed-forward type 2DOF PID algorithm and fuzzy control algorithm which have learning capable and online tuning capabilities. This controller is used in position loop of linear motor. Not only has it realized an online setting about PID parameter, but also it balanced the tracking performance and anti-disturbance issues of the single line motor. Then we conducted a comparative experiment about the vector control model which based on this algorithm and the traditional PID control algorithm at Simulink environment. The simulation results demonstrate the robustness of the algorithm is strong, and its tracking ability and anti-interference ability is very well.Second, through analysis, compared to the parallel synchronization control, master-slave synchronization and virtual master control and other types of control algorithms, cross-coupling control algorithm has better dynamic response and regulating capability on the control of dual PMSLM synchronous control problems. So this paper design a new cross-coupled controller which speed error and the position error is used as the input signal. While the output signal that after the processes by the cross-coupled controller is used to position compensation signal of the dual PMSLM. It realized the absolute synchronization about the speed and position of each PMSLM. Then the simulation and experiments have been carried out. It can be seen the speed error and the position error of the dual PMSLM is very small under the control of this algorithms from the simulation curve. The performance of the synchronous control system has been greatly improved.Finally, the AD5435 semi-physical simulation machine is used as the experimental platform and the software and hardware control system of the dual permanent magnet synchronous linear motors is designed.The dual PMSLM synchronous control algorithm is ported to the system to test its practical running situation. The results show that this servo system have good tracking ability as well as fine robustness, no matter what motor received disturbance, the system can be restored to a stable state (that is to say two PMSLM position keep on synchronization status) within a short time. |
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