Movement Control And Optimizing Operation Of CNC System

The development of relevant supporting technologies for CNC, the advancement of modern manufacturing and the revolutionary improvement for CNC system are mainly demonstrated by the high stability of system operation, high requirement of the control accuracy, the open architecture, the multi-function and intellectualization, etc. Based on this situation, in current study four aspects, method of transfer and error analysis for segment trajectory, improved acceleration and deceleration of trigonometric function two, leveled optimized algorithm and intelligent control strategies of CNC system, are studied in detail. In addition, the CNC system TDNC-H8, which is independently developed in our lab, is used to test the result.In view of the current trajectories connecting with straight line, circular arc, two methods of transfer and error analysis are elaborated in detail: To the connection with straight line, we analyse the relationship between different angle between velocity vector with transfer error and the interpolation surplus. To the connection with circular arc, we present different transfer methods and calculation on error, according to whether the current trajectory is in the same plane with the circular arc and the angle between current trajectory and the Tangent of circular arc,is presented, Finally, we proposed a curve fitting method, which is applicable to the connection of small or large straight lines, namely, using the characteristics of curve fitting to get maximum error point, and then using straight line for transition.An improved acceleration and deceleration algorithm of trigonometric function is recommended and elaborated the velocity planing according to the characteristics. For no uniform motion process, a solution of desired velocity is proposed by enumeration calculation method, To the look-ahead algorithm for velocity, paper introduces a new method according to the development trend of velocity.Based on the fact that the CNC system will ensure the core functions to run and that the functions are predetermined, an importance-leisure degree task scheduling algorithm based on the fixed priority and fuzzy control is put forward in this study. It will set the priority level of known tasks, and then use time and events activation response for periodic real-time and aperiodic real-time tasks. Based on the importance and priority level of tasks, an algorithm employing fuzzy algorithm to acquire execution time for a task is presented. It overcomes the existing shortcomings of conservative estimate. After that, depending on the importance, leisure degree of tasks and the logical relationship between different tasks, the priority is solved by the fuzzy algorithm. Finally, according to the operation feature of CNC system, a load shedding strategy, which is used to extended period of task, is presented to ensure normal operation of core functions of the system.An intelligent strategy is proposed according to the processing stage: pre-processing ----processing ---- after processing. At the pre-process stage, based on the process feature, paper uses the ant colony algorithm to optimize the objective of processing efficiency by changing the process parameters. At the processing stage, paper introduces the method of monitoring the physical state of tool based on the object. By using the fuzzy control method to timely adjust feedrate with the optimization target of cutting force stable with embedded the emergency-response program and interactive failure recovery, Using network technology, the physical information, operation information of CNC system, process information are realized remote data accessing, data sharing and fault diagnosis. And some research on the CNC system remote control and video monitoring, by which the interface of the CNC system and the operation are directly remotely got, are studied, and provide a new concept for the remote maintenance. Finally, the parts processing quality is tested without removal after processing, and quantitative analysis is made based on the measurement information which provides the data support for the follow-up processing.