Research On Multi-axis Linkage Simulation And Parameter Optimization For Servo System

With the presentation and development of the intelligent manufacturing technology,it has been paid more and more attention to acquire high precision and high performance CNC machine tool technology.Because high quality product can be manufactured only in the condition of improving the manufacturing precision of machine tool.In this paper,the knowledge of automatic control theory,dynamic modeling,motor control and so on,have been used to optimize controller parameters of machine tool to improve its performance in the condition of multi-axis linkage.It overcomes the limitation that optimization for the controller parameters of machine tool are mostly limited to single-shaft simulation and ideal control model.In this paper,the three-loop simulation control model was established for CNC machine tools based on dynamical model of servo feed system which was carefully analyzed.Cutting force,as an interference,was considered into control model to analyze the response of machine tool and observe the impact of cutting force by changing each parameter of machine tool.The curve path of command deviation was drawn to analyze the influence on command deviation by changing the gain of position or velocity loop.In order to illustrate the influence on command deviation of servo control system by the interference of cutting force,command deviation was also analyzed within or without cutting force and the corresponding difference value curve of command deviation was done.All the mentioned above have explained that the influence come from controller gain and cutting force on command deviation cannot be ignored.Also,the influence has no rules to follow.In this paper,differential evolution and its combination with simulation control model were researched based on the above simulation analysis.And the optimization experiment for servo control system was performed in the case of taking cutting force into consideration.The experiment was executed in the machine tool XK714 D and aviation cutting material-aluminum alloy T6061 was used for cutting work-piece.Cutting force generated by milling process was measured by dynamometer and roundness value of corresponding work-piece before and after optimization was analyzed.The influence on interpolation performance generated by control parameters between before parameter optimization and after parameter optimization was evaluated by three roundness features-the maximum,minimum and average value and the final results illustrate that the effectiveness of this optimization experiment has been verified.According to the research in the paper,the limitation in the traditional simulation for servo control system was changed.Four-quadrant interpolation algorithm was introduced in the simulation of control system.In the meantime,cutting force generated by machining process was also considered into the control system.Their combination made the feed system simulation closer to the actual situation.At last,the parameter optimization experiment based on cutting force on the condition of multi-axis linkage have verified the effectiveness of the method proposed in this paper.