Research And Application Of The Coupling-Axis Control Techniques In Numerical Control System

Coupling-axis function is the important component of the systematic functions in high-performance CNC system as a representative control function.The abstract model is built for the research and application of coupling-axis.Based on this coupling model,functions like rigid tapping with frequency converter to control spindle,spindle synchronization,gantry synchronization,and electronic gearbox are developed and applied on domestic CNC system.This paper proposes the concept of reference axis and following axis according to application form and application characteristic of the coupling-axis.Then the author summarizes out two essential factors based on the following two concepts: coupling-axis group and coupling-axis relationship.Finally model of coupling-axis group,coupling-axis relationship and coupling-axis function is built with the thought of object-oriented.There is instruction response delay in rigid tapping with frequency converter to control spindle.This paper summarizes out the rule of spindle motion,and then spindle motion model is built to control feeding axis’ s motion based on encoder’s feedback.For the problem that the following error of feeding axis fluctuates tempestuously,parameters such as velocity compensation coefficient,acceleration compensation value and position proportional gain are adopted to compensate.For the controlling tasks of multi-spindle workpiece exchange and polygon machining,this paper proposes two-phase synchronization method according to the inconformity of spindle motion status before synchronization process and the requirement of repeated processing.5-phase acceleration and deceleration controlling method is adopted to solve the problem of acceleration skip when adjusting phase angle.Finally this paper analyses the machining parameters of regular polygon based on the principle of hypocycloid.There is overlarge difference of load current between gantry synchronization axis which is connected by rigid structure.To solve this problem,this paper adopts automatic compensation method and manual compensation method to measure position compensation value and the following two methods’ compensation effects are contrasted.For the controlling tasks of the hobbing of high-precision gear,electronic gearbox is proposed to implement coordinated movement based on parallel electronic gearbox structure in this paper.Then the author analyses encoder-axis’ s controlling principle which is regularly used in electronic gearbox and designs encoder-axis class based on the model of coupling-axis group.Finally the synchronization coupling coefficients in hobbing machining are analysed when electronic gearbox is applied in it.The above-mentioned application functions of coupling axis controlling technology are developed on HNC-8 Numerical Control System,and the following axis is controlled in coupling-axis controlling channel.Finally more than 20 functions related to coupling-axis are developed and verified.These functions have been tested by National Detection Centre and are equal to SIEMENS 840 D numerical control system.