Research And Implementation Of B-Spline Interpolation Algorithm For Industrial Robot Based On LinuxCNC

Interpolation algorithm is the core technology of CNC system,it has a direct impact on the numerical control machining's effect.It is one of the urgent needs to improve and perfect the NC technology.At present,most of the existing CNC systems have only achieved a simple linear interpolation and circular interpolation algorithm,resulting in the system can not directly process complex curves.If we want to process a curve,we can only use a series of small straight lines and small arcs to approximate the curve.But using this method will seriously reduce the processing efficiency and accuracy.So in order to improve the processing efficiency and precision,this paper implements a B-spline curve interpolation algorithm on a open source CNC system software called LinuxCNC,resulting in the system can process complex curves directly.And by adding a robot kinematics algorithm module,the system can also support industrial robots.Linux CNC system has many advantages,such as open source,high precision,good real-time performance,so this paper chooses to use LinuxCNC system as the implementation platform of the following algorithm.This paper first introduces the software structure and working principles of the Linux CNC system and then gives us a detailed analysis of the working principle of task controller and motion controller,so that we can know the theoretical basis of the implementation of trajectory planning and interpolation algorithms.At the same time,the basic kinematics algorithm of robot is introduced.Taking the PUMA560 robot as an example,the process of D-H parameters modeling and the derivation of its kinematics equation are described in detail.Then,the kinematics algorithm of PUMA560 robot is implemented in Linux CNC system.Then,according to the shortcomings of traditional trapezoidal and S-shaped acceleration/deceleration control algorithms,this paper introduces a digital convolution based acceleration/deceleration control algorithm,which can ensure the realization of the algorithm is simple,time complexity is small,and can also make the system run smoothly.In the start phase and stop phase,the system will not produce any shocks and oscillations.Based on the new acceleration/deceleration control algorithm,this paper further studies a three-time B-spline curve interpolation algorithm,which makes the system can process complex free curves and implements it on LinuxCNC.Finally,this paper used Python programming language,combined with QT,OpenGL graphics library to design the robot interface and PUMA560 3D simulation model,thus a set of high-performance robot software control system was completely developed.At the same time,in order to verify the correctness of the algorithms,this paper carried on a simulation experiment of kinematics algorithm and the B-spline interpolation algorithm respectively.The experimental results show that the algorithm is implemented correctly on the Linux CNC system and we have achieved the expected goal.