Research And Implementation Of PLC And Acceleration/Deceleration Technology For The Embedded CNC

The control precision and efficiency of NC system is still the lasting theme in its development. PLC module and acceleration/deceleration module are the main function modules in CNC, PLC module mainly completes the control on the auxiliary function of CNC machine, acceleration/deceleration module controls the velocity in the process of feed motion. Improving the design of the PLC module and the acceleration/deceleration module can optimize the operating efficiency of the system effectively and improve the working precision.PLC mainly exists in the form of soft PLC in CNC which consists of development system in host computer and operating system in target computer. Firstly, optimizes the design of software PLC for embedded CNC and improves the compiler of software PLC development system running in host computer, realizing the transformation from instruction language to ladder diagram.Then the openness of embedded software PLC is studied, achieving the optimization design in which closed PLC transforms to open PLC. Finally, in order to improve the operation efficiency of PLC sequence control program, hierarchic process to PLC program is designed to improve the real-time response.The CNC can obtain flexible velocity profile curve through the acceleration/deceleration control module, reducing the shock and vibration of machine tool and improving the machining precision of the workpiece. Next, the acceleration/deceleration control is researched, designs and realizes the linear type and S type acceleration/deceleration control after interpolation based on the theory of digital filter, and the error constraints of acceleration/deceleration control after interpolation are also derived. The control scheme of configuring acceleration /deceleration through setting parameters is designed. The relationship between the parameters and the precision and efficiency is also studied for the sake of giving the suggestions of the setting of parameters so as to optimiz acceleration/deceleration parameters, and simulation results using MATLAB are presented to varify the practicability of the schmes above.Finally, the overall scheme of embedded system is researched, and studies the implementation method of parallel multi task of the CNC software under different schmesand, through the machine test, validates the optimization results of the PLC module, and verifies the effectiveness of the comprehensive acceleration/deceleration control through designing the parallel tests.