Research On Robot Surface Grinding Based On Mixed Force Control

Grinding and polishing is a fairly important process for the surface quality of the workpiece.Nowadays,some markets are also dominated by conventional manual polishing and grinding,and manual grinding is not only difficult to ensure surface quality,but also inefficient,resulting in unqualified products and potential safety hazards.This article is based on robotics and grinding and polishing processes,study the kinematics,dynamics and control laws of robots,a force level mixing control strategy is proposed to optimize the process parameters and greatly improve the surface grinding accuracy and efficiency.Firstly,the paper applies the German KU-KA robot KR120,using the standard D-H method,the structural parameters of the robotic arm of the robot and the posture transformation matrix of each joint were determined to find the kinematic positive solution and the inverse solution.The MATLAB software is used to solve the working space and simulate the positive and reverse solutions.For trajectory programming,the 3rd,5th and3-5-3 piecewise polynomial interpolation methods are introduced.Through the analysis,the3-5-3 piecewise polynomial interpolation method is adopted,and the interpolation method is analyzed by using MATLAB simulation software,the simulation obtained the 6 joints of the robot,and the changes of angular displacement,angular velocity and angular acceleration were obtained,analyze the smoothness of the curve and explain the rationality of the trajectory planning method.Secondly,in order to analyze the robot dynamics,calculate and solve the Jacobian matrix,the Lagrange method is used to establish a dynamic model and obtain the expression of the dynamic equation.Through ADAMS simulation software,the built model is solved,the change curve of each joint force(moment)with time is obtained,and the dynamic model is verified.In further research,a force-position hybrid control method was investigated to achieve force level mixing control grinding.Create an active compliance model with one end connected to the end of the robotic arm and the other end to the grinding tool.The force control model of the smoothing device is established,the force balance equation of the smoothing device is calculated,and the output of the force control flange is adjusted and controlled by the fuzzy PID control method;For position control,combined with the robot controller,and the upper computer is used for position and pose compensation to realize the closed-loop control of the robot shutdown angle;Verify the force control effect of the fuzzy PID control method,and select the front surface for force level control and polishing,mainly aimed at force tracking experiments,the results show that the method has a good control efficiency.Finally,surface polishing experiments were carried out.In order to get a good surface quality of the workpiece,first,some of the main factors affecting the quality of grinding are analyzed,and single-parameter variation experiments are designed for parameters such as grinding throwing force,feed speed,sandpaper mesh,etc,and the relationship between each parameter and surface roughness is obtained.The orthogonal test was used to obtain reasonable grinding process parameters;In order to further verify the practical application of the force level mixing control strategy,the curved surface of the workpiece of the body panel is polished.The experimental results show that the grinding method is improved by using the force level mixing control strategy method,and the grinding accuracy is improved and good surface quality is obtained.