Study On NC26 Thread Processing Method Based On Dual Industrial Robots

Industrial robots were extensively used in companies to replace manual labor and hazardous operations.Thus,the level of intelligence and safety management of companies was ascended.Lathe is currently the main equipment for thread processing.The development of lathes has also progressed from basic manufacturing to automatic CNC.However,due to the fixed structure of the lathe,some large-scale or structurally complex parts still have problems such as difficulty in clamping or insufficient freedom of processing.Therefore,this paper presents a method of using two industrial robots to complete the thread processing.With the characteristics of high flexibility and adaptability of dual-robots,it can produce more clamping and machining trajectory schemes to complete the processing of special parts threads.In this paper,the RB50 robot is used as the thread processing system and NC26 thread as the research object,and a complete thread processing technology is formed.The kinematic analysis and dynamic analysis of the dual robot and the calibration of the dual robot system are performed,and the thread processing process is solved.The rigidity problem of robots and the problem of coordination of dual robots have expanded the application of industrial robots and solved the problem of thread processing for special parts.Firstly,a simple linkage model of the robot,using DH coordinate system,based on the structural characteristics of the robot,is established.Then the robot positive kinematics equation is obtained by using the DH parameter method.Furthermore,the inverse kinematics of the robot is performed by using the analytical method.In addition,robot trajectory simulation and thread Processing trajectory programs were completed by using ADAMS software.The robot speed programs under three different displacements and time schemes were discussed.The movement periodicity of the robot in thread processing running is 23 seconds.Secondly,the loads of the two robots in processing threads under three different cutting schedules are calculated in this paper.A 3D model of the six rods structure of the robot is created by using the Inventor and imported into the ADAMS software for dynamic and movement analysis.The dynamics and the maximum torques at rod joints under three different schedules are analyzed.Simulation results show that Program-3 meets the stiffness requirement of processing the thread of NC26.Because the absolute positions and the relative positions of these two robots are uncertain,the transformation relationship between the two coordinate systems of these tworobots is derived,and the calibration of the two-robot system is carried out.The transformation matrix of these two coordinate systems is derived,which is solved by using singular value decomposition.This method requires no complicated equipment,has high calibration accuracy,and is convenient for application.Thus,it is very suitable for production site.Finally,two RB50 robots were used in the laboratory to form a thread processing system,and a conical acrylic rod with a diameter of 16 mm,instead of the drill tool joint,was used to conduct the processing experiments.A digital measurement projector was used to measure the manufacture accuracy in the processing experiments.Experimental results show that the drilling tool joint thread processing system based on two industrial robots meets the requirements of processing quality and economic efficiency.The two robots processing system proposed in this paper is feasible for the thread and drilling tool joints processing.Therefore,it provides a foundation for extending the uses of robots in manufacturing.