Study On High Precision NURBS Interpolation Technology

High speed/high precision motion control is an important research area of machinery manufacturing, and is the core of CNC machine tool components. Interpolation module is the core module of motion control system. High-speed, high-precision, complex trajectory of motion control technology is the hot research of current motion control technology. NURBS curve interpolation technique is typical. The real-time of NURBS interpolation reflected in control systems, Only NURBS interpolation time is less than or equal to the control system set interpolation cycle, Interpolation technology meet the real-time nature. NURBS interpolation curve containsa wide range of frequencies, If these frequencies included with the same natural frequency components of implementing agency, it will inevitably cause resonance. To solve this problem, the literature has been used Notch filter mode to handle.Based on the existing research work of NURBS technology, A DSP-based Motion Controller interpolation algorithm have been implemented. By the improved algorithm of exploring iterative interpolation method, the pre-estimate formula in the form of 2-order differential equation have been replaced by pre-estimate formula in the form of 1-order differential equation, confirm the u monotony accession strictly. It could avoid the interpolation direction converse and oscillation.On the basis of implementing the DSP-based interpolation control, interpolation data will be processed by notch filter, interpolation of data obtained from the data buffer plate after of DSP directly into PC by Serial for data processing and analysis. Notch filter design is based on MATLAB Signal Processing Toolbox. Selection four groups of line, circle, star curve, the bridge-shaped curve with different geometrical characteristics as a test target. After filtering, according to statistical indicators, their errors of evaluation and analysis Stability mainly from the speed and position accuracy have been discussion. According to the simulation results, the linear does not contain any frequency components, the resulting error is very small. Yuan smallest deviation of the position can be controlled in 4^μm, the location deviation of star-shaped and bridge-shaped in 1^μm, it is entirely possible to achieve high-precision, and the speed has been very stable. Thus, we can define Notch Filter implementing to solve the problem of resonance with agencies, Interpolation can guarantee the accuracy of the location and speed stability.