Research On The Speed Smooth Interpolation Algorithm Based On CNC System

CNC technology is the core technology in current high-end equipment manufacturing industry,which plays an important role on the development of China's manufacturing industry.The sudden points are always encountered in the CNC machining,which will bring about a sharp change in speed,cause vibration of the machine and reduce the processing quality of the product.The speed smoothing interpolation algorithm proposed in this paper can detect the speed mutation point on the processing path in advance and realize the smooth transition of the feed-rate,which prevents the machine vibration and improve the machining precision and processing stability of the product effectively.The main contents of this research are as follows:(1)Research on Acceleration and Deceleration Algorithm in the CNC machining.This paper mainly analyzes the different acceleration and deceleration characteristic curves,and uses the simplified S-type acceleration and deceleration method to plan the speed of various processing paths.The error between the actual interpolation speed and the theoretical planning speed is taken into account,and the algorithm of error correction based on S-type acceleration and deceleration curve is designed,which establishes the theoretical basis for the study of velocity interpolation algorithm.(2)Aiming at the continuous micro-segment processing path,an adaptive velocity forward-looking control algorithm for continuous micro-segments is proposed.Firstly,the geometrical characteristics of the continuous micro-segment are analyzed,and the number of forward-looking segments is adjusted adaptively.Then,the forward distance is determined according to the speed of the forward-looking demarcation point,and the possible cutoff points are found,and the speed of the prospective demarcation point is re-optimized.Finally,the S-type acceleration and deceleration method is adopt to carry out acceleration and deceleration planning on the processing forward section,and improve the processing efficiency while realizing the smooth transition of feed-rate.(3)Aiming at the characteristics of spline curve,a B-spline interpolation algorithm based on S-type acceleration and deceleration with interference preprocessing is proposed.Firstly,the interpolation speed is adjusted adaptively according to the curvature of the spline curve,and then the velocity cusp is determined according to the speed minimum,and the curve is segmented by the velocity cusp.Finally,the interference points on the curve are found according to the velocity difference of adjacent velocity cusps.By comparing the interference points,the acceleration and deceleration planning is carried out on the segmentation curve.While satisfying the smooth transition of the feed-rate and acceleration,to ensure that the jerk can meet the acceleration and deceleration capacity of the system.Finally,the validity of the above algorithm is verified on the multi-axis motion platform of X-Y linear motor.The experimental results show that the machine can improve the machining precision and processing efficiency under the premise of meeting acceleration and deceleration capacity of system.