Study On Self-adjusting Clamping Technology Of Machining Datum For Aviation Stringer Parts

In recent years,the rapid development of China’s aviation manufacturing industry,aviation manufacturing technology to automation,intelligent development needs more and more urgent.The new aviation equipment with high reliability and high service performance has higher and higher requirements on the structure and quality of components.In order to meet the requirements of the design and manufacture of modern aviation equipment,the structure and type of components of aviation equipment are gradually developing towards the direction of integration,lightweight and high precision.In aeronautical equipment manufacturing,rivets and bolts are widely used as components,which are gradually replaced by large integrated parts.In order to achieve the purpose of lightweight equipment to improve performance,without damaging its own structural performance,the parts are designed with complex curved edges,holes and other structures,which improve the difficulty of processing and manufacturing.In addition,the complex workpiece structure and process characteristics,so that the fixture design becomes complex.The development of automation and intelligence of tooling and fixture lags behind relatively,which becomes the shortcoming of numerical control machining process of aviation structural parts.The purpose of this paper is to make an in-depth study on the problems of deformation and hard clamping of a series of aviation stringer parts which are widely used in aviation equipment.In this paper,the process characteristics and clamping difficulties of aviation stringer parts are analyzed.A clamping scheme of module was designed,in which the part web and the inner surface of the flange to be machined were taken as the positioning surface and the cylinder drove the side jacking block to clamp.The clamping position and the size of the clamping area of the clamping structure are optimized by using the simulation software.Aiming at the difficulty of machining datum correction in the process of clamping,a self-adjusting clamping control method was proposed.The bending deformation of aerial girder is analyzed and abstracted as a simple beam structure.Based on the theory of bending and deformation of simply supported beam,the parameters that affect the deformation correction force of parts in the process of clamping and alignment are analyzed.A clamping mathematical model was built to describe the relative position of the parts and the clamping modules and the relationship between the various elements of the tooling and the parts in the clamping system.Using fuzzy control method,the deformation correction controller of each clamping module is established.In the process of clamping,the straightness of machining datum of parts is adjusted and the results are revised to realize the machining datum correction of aviation stringer parts.Finally,on the basis of the clamping structure design simulation and clamping control method research,the detailed pneumatic,electrical and control software design is carried out.A set of automatic tooling system is developed,and a comparison test of clamping is designed.The test results verify the reliability and practicability of the design of the clamping scheme and the clamping control method.The developed tooling system can meet the clamping requirements of the numerical control machining of the aviation stringer parts.