Study On The Acceleration/Deceleration Algorithm And Positioning Technology Of CNC System

As the core of computer numerical control (CNC) technology, CNC system is ofparticular importance to study. The acceleration/deceleration (ACC/DEC) control algorithm,one of the key techniques used in CNC system, is studied in the paper, and the constructionprinciple of the flexible ACC/DEC algorithm function, two flexible ACC/DEC algorithmsand the endpoint control algorithm of S-shape curve ACC/DEC algorithm are introduced.Those works are drawn as follows:(1) Some problems existing in the presently conventional exponential ACC/DECalgorithm and linear ACC/DEC algorithm are analyzed. The paper indicates that impact andvibration do harm to CNC machine tools, and the cause of impact and vibration is analyzed.The construction principle of the flexible ACC/DEC algorithm function is introduced.(2) The trigonometric function ACC/DEC algorithm and the polynomial ACC/DECalgorithm are introduced according to the construction principle of the flexible ACC/DECalgorithm function, and their mathematical models are provided. All kinds of possiblecircumstances are analyzed in the trigonometric function ACC/DEC algorithm. At thesituation that the displacement of the algorithm is short, two acceleration ways or twodeceleration ones are proposed, and the total time of two ways is compared. All kinds ofpossible circumstances are analyzed in detail according to the differences of initial velocities,endpoint velocities and displacements in the polynomial ACC/DEC algorithm. Finally, twoACC/DEC algorithms are simulated with MATLAB, and the simulation results show thatvelocities, accelerations and jerks are consecutive and they avoid well flexible impact.(3) Some positioning problems in the conventional ACC/DEC algorithms are analyzed.The endpoint control algorithm of S-shape curve ACC/DEC algorithm is proposed to solvethe problems above. The deceleration point is predicted exactly according to the algorithm,and the deceleration point error is compensated at higher federates, so the ACC/DEC time isshortened, and the positioning stage is almost cancelled. Compared with that of conventionalS-shape curve ACC/DEC algorithm, the system performance has been significantly improved.The polynomial ACC/DEC algorithm, the trigonometric function ACC/DEC algorithmand the endpoint control algorithm of S-shape curve ACC/DEC algorithm have very strongvalues for expansion and application, studies and conclusions of this dissertation could give some guidance in research and development work of Chinese CNC machine tools.