| The roll-forming product is widely used in construction,automotive,aerospace and other fields,because of its characteristics of good surface quality,high material availability.With the development of the industrial technology,the demand for high-accuracy plate engender high-accuracy equipment.This paper is focused on improving the accuracy of the single-axis flexsible-rollforming machine developed by the North China University of Technology.The single-axis flexible-rollforming machine could produces one-axis variable cross-section roll-forming steel plate,which has the characteristics of low cost and easy to control.In the process of flexible-rollforming,the change in sheet cross-section is achieved by moving the forming rolls controlled by the servo motors,whose accuracy being close related to the control accuracy of the servo motors.Therefore,one of the important work of this paper is to improve the synchronization performance of single unit in the flexiblrollformingmachine.On the dual-motor servo control system with the PXI controller,NI7350 motion control card,a large number of experiments has been made analying and comparison the synchronization accuracy and tracking error of parallel control,master and slave control and other synchronization control strategy.A coupling control strategy based on PID deviation is proposed to improve the synchronization precision of dual-motor system,whose effectiveness being verified by the servo motor no-load test and the unit experiment.Taking into account the uncontrollablity of the plate-speed in the rollforming process,AutoCAD graphics is discretized into the control program to reduce the effect of the plate-speed deviation,and to improve the rollforming accuracy of the equipment.In addition,As an important factor affecting the control accuracy,the plate-speed in the bending process will subject to various factors.By the sensor-combination,the real-time plate speed is estimated resonable to improved the linkage control accuracy of multi-units. |
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