Research On Five DOF Hybrid Polishing Robot With Force Control

At present,the market demands more and more high quality of polished products,especially the small and medium-sized manufacturing enterprises in the Pearl River Delta.The traditional manual polishing method is harmful to health,which makes it difficult to recruit workers in polishing industry.In addition,multi-axis CNC grinding machine and industrial mechanical arm are often used in industrial production line.Although they can meet the requirements of production automation and high efficiency polishing,the high cost of equipment restricts the development of polishing industry with low profit.Therefore,this project is devoted to the research and development of low-cost polishing robot system and its control strategy,which has far-reaching significance for improving the production chain efficiency of polishing industry,avoiding low-efficiency repeated work and ensuring the polishing effect of workpiece.In the first chapter of this paper,the structural characteristics and existing problems of two kinds of polishing equipment in industrial production line are analyzed based on the current development level of polishing industry,and then the research direction of common constant force control strategy and new constant force control strategy are described.In the second chapter,it introduces the overall mechanical structure and working principle of the five DOF polishing robot,and analyzes the motion characteristics of the passive constant force control mechanism to achieve position control.According to the performance requirements of the control system,select appropriate components(such as the main controller,electrical proportional valve and pressure sensor)to complete the construction of the control system.In the third chapter,the kinematics model of polishing robot is analyzed,and the polishing ability of different shapes of workpieces is verified.Then,the polishing mechanical model of a general workpiece is modeled,and the changing rule of polishing positive pressure with the workpiece contour is deduced,which theoretically verifies the robot's constant force polishing ability to complex surfaces.In the fourth chapter,the polishing robot is modeled in Adams environment,and the correctness of the mechanical model is proved by comparing the simulation and theoretical calculation results.Then,a polishing robot experimental platform is built to carry out many polishing experiments of different shapes.The experimental results show that the polishing robot has good constant force polishing performance.In the fifth chapter,the active control strategy of polishing positive pressure is proposed by combining Deep Q-Learning algorithm.Firstly,the feasibility analysis of the transition from Markov modeling of polishing robot to the application of Deep Q-Learning is carried out.Then,the polishing environment model is designed based on the polishing mechanics formula in the previous chapter.Finally,the training is completed quickly and the good control effect is obtained through the finite simulation experiment.