Research On Motion Control Of High Speed And High Precision Laser Cutting Robot

Laser cutting technology is one of the most important application technologies in advanced industrial manufacturing at present,which is widely used in the field of application.It has the advantages of high speed,high precision,strong versatility of cutting materials and less pollution,and has become one of the research hotspots of current advanced production technology.Although laser cutting technology has made considerable development in China,but there is a certain gap comparing with leading foreign companies.The current high-speed and high-precision laser equipment still uses imported expensive equipment as a channel,which seriously hinders the promotion and popularization of laser technology in China.In order to improve the manufacturing capacity of China's advanced industrial products,it is of great significance to study the more efficient motion control capability of laser cutting on complex curved surfaces.First of all,this thesis takes the laser cutting robot with three-dimensional laser head with new mechanical structure as the research object.From the kinematics point of view,the motion decoupling relationship between the mechanical rotation point(M point)fixed on the laser head and the prismatic joint of the robot in the X,Y and Z directions is analyzed.A step-by-step kinematics analysis method is proposed to analyze the robot with decoupling mechanical structure.The objective cutting point is divided into two steps from the operating space to the joint space for kinematic forward and inverse analysis.Secondly,this thesis studies the interpolation technology of laser cultting tool path.In order to achieve the optimal cutting speed and high cutting quality,a real-time interpolation algorithm based on low curvature M path is proposed.Taking the corner as an example,the interpolation algorithm of high curvature section is studied.Firstly,the digital path method is used to calculate the tool path interpolation and the laser beam attitude adjustment planning,and then by controlling the real-time interpolation position of the M point on the low curvature M path,the laser focus point is controlled to perform a uniform cutting motion on the complex curved surface.Finally,based on the common acceleration and deceleration algorithm,the problem of the smoothness and stability of the robot motion control is caused by the discontinuity of the acceleration or jerk curve in the numerical control system.This thesis studies the control method of S-type acceleration and deceleration and acceleration and deceleration filtering technology.It is proposed that the problem of poor continuity of the acceleration curve after trajectory interpolation is solved by the method of series moving average filter after M path interpolator.The whole algorithm process of the thesis is realized by Matlab software and its related Robotics Toolbox,Simscape Multibody and other toolboxes.The robot physical model is established and the motion characteristic curve is calculated by programming the algorithm.Smoothing the velocity curve under the interpolation algorithm based on the M path to reduce the impact of the acceleration and deceleration mutation on the driving motors.The results show that the position of the M point has little effect on the cutting speed after the filter change.This motion control strategy has certain feasibility.