Stiffness Analysis Of Drilling And Riveting Robot During Drilling

Due to the low stiffness of the serial robot, when the robot is carrying out drilling operationwould produce elastic deformation and vibration. Stiffness of the serial drilling robot plays a crucialrole in hole quality. In order to meet the requirements of the aircraft manufacturing field, the serialrobot must be researched including stiffness, damping, model of drilling force and so on. Four aspectsof the serial drilling robot have been researched in this paper.1. Using Denavit-Hartenberg-modified method to establish coordinate system, and have acquiredthe jacques than matrix of the robot by using differential transformation method. Identifing stiffnessmatrix and joint stiffness considering the displacements of the robot for a applied load, and thehypothesis have been verified.2. The dynamic model of the robot consider damping has been established, the joint dampingcoefficients and material damping have been concluded by using the logarithmic decay method andrayleigh damping model. The dynamic model of the serial robot considering joint stiffness anddamping have been got by using finite element method. Finally mode analysis of the robot underdifferent gesture.3. Start from the normal rake of the vice cutting edge of the twist drill, the end section curve havebeen constructed segmentation. After the intersection of the end section curve along the spiral andcone, we will get the main cutting edge of the twist drill. The cutting force have been modeled andforecasted by combine the oblique cutting model and material properties.4. Through experiment, the natural frequency and cutting force of the robot have been measured,and compared to predicted value. The model of cutting force and the finite element dynamic model ofrobot have been checked.The dynamic and finite element model of the serial robot considering joint stiffness and dampinghave been build. The model of cutting force based on the analytical model of the drilling main cuttingedge have been established. And the cutting force and natural frequency of the robot have beenanalysised, and compared to the value of the experiment. It indicated that the dynamic model of therobot and the cutting force model can reflect the dynamic characteristics of the drilling robot system.It will give advise to the choice of manufacturing technology and motion planning in the future.