Study On The Motion Control Principle Of Free Elbow Pipe

Complex free-bending metal pipe fittings have the advantages of high strength,high stiffness and light weight,as well as material saving and beautiful appearance compared with traditional structures.Therefore,it is widely used in many fields such as aerospace,marine industry,automotive manufacturing,etc.However,very little is known about the forming motion control of articulated oscillating type CNC free bending in China.Therefore,this paper is based on the principle and process of articulated oscillating free bending process and the study of forming motion control principle.The specific research contents are as follows:First,different motion control processes for forming motion are proposed and analyzed.Through the analysis of the forming principle and process of free bending process,the bending process of the tube is described as "segmental processing",and different control processes of tube offset and tube advance are proposed;based on the numerical simulation of elasto-plasticity,the forward and backward sliding motion of the tube is analyzed for the evaluation of forming quality.Then,based on the process principle and process of free bending,the mathematical model under the coordinated motion control relationship is established.For the coordinated motion state of pipe advancement and bending die offset,the mathematical relationship of pipe bending and forming motion process is studied and analyzed,and the relationship between offset speed and time is solved when the advancement speed is certain;the mathematical model of rebound prediction is solved,the solution formula of rebound angle and rebound radius is given,and the influence law of different material properties and different parameters on rebound is analyzed.Further,the constraints that control the relationship between process and motion are studied and analyzed.The forming capacity of the pipe bending and forming equipment itself and the plastic forming limit of the pipe are studied and analyzed,and the constraint relationship and the pipe quality evaluation criteria due to the equipment structure are given;based on the numerical analysis of elasto-plasticity,the free bending and forming process is modeled and simulated,and the forming quality under different propulsion speed and different offset speed is analyzed and evaluated.Finally,the intelligent control system of free bending forming is studied and analyzed.The database classification summary of the existing simulation data and the measurement data of the equipment after bending and forming,the overall design of the CNC free bending intelligent control system,the design of CNC free bending forming process database structure framework,and the use of neural network intelligent learning method to initially establish a prediction model for bending prediction.In this thesis,the principle of motion control of free bending process is studied for the principle and process of free bending,and the mathematical model of the motion relationship of forming control process is established to provide the theoretical basis for this process design and quality control,and to provide the technical theory for further research of intelligent control.