Study Of Acceleration/Deceleration Control Algorithm In CNC Interpolation

In the interpolation process, the precision and the speed of acceleration/decelerationcontrol is an important target of the CNC system, which determines the performance of NCsystem. This paper has made the in-depth theoretical and applied study based on these twoaspects.The acceleration/deceleration control is the important component part of the NC systeminterpolator and one of the key technologies of the NC system development. The objective ofNC is to achieve high-precision and high-efficiency machining. This paper presented a usefulspeed control method applied for a programmable timer of DSP peripheral facilities, separatedthe acceleration/deceleration description with the system program, only need to change thedata of the programmable timer independently to generate a series of pulses with desiredfrequency when to change the acceleration/deceleration characteristic, thereby to control thespeed of servo motor instead of revising of NC system program. Thus, theacceleration/deceleration control law of system can be changed conveniently according toactual situation and the best dynamic performance of machine tool can be obtained.This paper is divided into five chapters. Chapter one mainly introduced the developmentprocess, present status and the development trends of the NC technology, and then pointed outthe significance and the main content of the study. Chapter two studied the interpolationalgorithms and the classification of interpolation, and analyzed the opened-loop andclosed-loop control characteristics of the feeding movement, its influence to the processingaccuracy, and the error compensation solutions. Chapter three introduced the principles andfeatures of the step motor first, then studied the servo motor controller based on the givenpulse mode, and analyzed the linear and the S-curve acceleration/deceleration control methodsunder the assigned pulse control mode. Chapter four mainly introduced own study on thespeed control method based on the programmable timer of external instrumentation of DSP. Abrief description of the embedded systems including the DSP is introduced, and then analyzedthe principle of the speed control algorithm and the simulation and experiment of thisalgorithm. The last chapter summarized the conclusions of the research and the futuredevelopment of the prospect.