Research On Impedance Control Method For Industrial Robot Grinding Processes

With the continuous development of modern machining,it is a hot spot to use robot grinding to replace the manual operation not only improves the quality of grinding,but also reduces the cost of production.During the grinding process the grinding force affects the machining quality of workpieces and the life of the abrasive belt,therefore,it is the great practical significance to research the force control method for the robotic belt grinding.Facing the defects of using manual grind the tap surface,the robot is taken as the control object which is used to grind the water tap,the force tracking impedance control method is studied combining off-line programming to realize the compliance of the robotic belt grinding.In order to improve the efficiency and the quality of belt grinding,the main works of the thesis are described as the follows:Firstly,the structure and the processing method for the robotic belt grinding system is introduced.The machine of belt grinding is studied.The elastic contact state of abrasive belt grinding process is analyzed from macroscopic angle,and the cutting mechanism of single abrasive grain is studied from microcosmic angle.Furthermore,improving the quality and efficiency of grinding as the research target is proposed,and controlling grinding force as a method is achieved.Secondly,the kinematics equation of the ER50 robot as the object is established by using the D-H method,and the inverse kinematics solution is derived,the vector product method is used to solve the Jacobi matrix.On this basis,the three step spline curve is used to generate the grinding trace in the off-line programming environment.The grinding experiments are then carried out and the experimental results are analyzed.Thirdly,the contact force is analyzed in the robotic belt grinding process.A force tracking impedance controller is designed,which is adaptively compensated the elastic deformation with contacting.And the stability condition of the whole system is analyzed.Then considering the realization of industrial robot,a position based force tracking impedance controller is designed.On the basis,the machining path which is generated in the off-line programming software is dynamically adjusted,tracking the desired trajectory,thereby achieve the constant force of the robot grinding.Fourthly,the virtual prototype of the abrasive belt grinding system in ADAMS is established considering the material of the abrasive belt and the contact wheel and the complex dynamics in the contact process.A co-simulation platform for the control system of robotic belt grinding is built by ADAMS and MATLAB.Then using position based force tracking impedance control method in experiments,which verify the effectiveness of the algorithm.Finally,the work of innovation and shortage is summarized,and some works are prospected in the future.