Applied Research Of Micro-displacement System With High Speed And Precision Based On EtherCAT

At present, non-circular profile pistons have predominated. But it is impossible for the traditional lathe to machine. Therefore, the micro-displacement system with high speed and precision used to process non-circular profile pistons has been a key technology for non-circular lathe. So far, for most of the manufactures, the customized controllers based on DSP are developed to position the tool. Not only does it need long time, but also it becomes more complex. So, in this paper, a new scheme to build the micro-displacement system based on EtherCAT is proposed. Main contents of the research are as follows:Firstly, the structure of the whole system is introduced particularly in mechanics, electrics and software. By analysis of the control technique based on EtherCAT and TwinCAT system, it is concluded that the proposal is feasible theoretically. And then, it is realized with PLC and C#.Secondly, by analyzing the kinematics of the tool holder, the model structure of the closed position loop is built. By the method of scanning frequency, the parameters of the model are identified and, then, establish the system model. With this model, the offline phase-amplitude regulator in frequency domain is designed to realized the adjustment of the input signal.Thirdly, through the research on the trajectory planning of non-circular piston and offline phase-amplitude technique, the discrete data is generated and the online interpolation is implemented. In addition, the software is developed to create the data used to process pistons.Finally, by the experiment, the dynamic parameters of the closed position loop are set. By the no-load experiments about the standard ellipse shape, the modified ellipse shape and the shape combining ellipse and circle, the compensation effect under high frequency of the offline phase-amplitude regulator in the condition of 3000r/min is verified. The final cutting experiment shows the machining precision can be as high as ±2um, which meet the process demand to some extent.