Basic Research On Assembly Location Technology Of Aircraft Cable Harness

Cable harness as an important part of the transmission of power and electrical signals on the aircraft,the laying of the position throughout every corner of the aircraft,such as the fuselage,wings,engine compartment,landing gear,etc.,similar to the human body's neural network.Therefore,the rationality of aircraft cable harness laying,the correctness and reliability of the fixing and connection will affect the normal working conditions of the aircraft,and even endangering safety.However,the assembly location marks required by the current process files are not displayed on the manufactured wiring harness,and the position of the location point and the fixed point on the wiring harness needs to be manually determined when assembling the wiring harness.The lack of the location marks on the harness significantly increases the workload,reduces the efficiency,and makes the length control of the harness become difficult.In order to solve the above problems,this dissertation studied the design rules of the cable harness through analyzing the harness data,and took basic research on finding the harness locating points intelligently.Meanwhile,outputted the 2D flat diagram including the assembly location information to serve the harness manufacturing department.The main research works and innovations in this dissertation are as follows:1.Summarized the general design rules of the cable harness.By analyzing the data and structural characteristics of the wire harness,it is concluded that the wire harness is composed of branches,and the branches are composed of the bundle segments.The laying route determines the branch direction and the branches of the wire harness generate bundle segments.Proposed a method of inserting the end points of the bundle segments into the points' sequence of the laying paths.The position sequences of the points on the cable are obtained.2.It established a hierarchical data model of the cable harness based on the father-son branch.Through the deep analysis of the harness data,the judgment method of the parent-child branch of the harness is put forward,and the relationships among the root branch,the first-level sub-branches and the second-level sub-branches of the cable harness are expressed by the hierarchical model.In the process of constructing harness hierarchy intelligently,four kinds of pathological harness are summarized and the corresponding correction methods are proposed.3.Proposed a new method of calculating the flattening angle of the wire harness-the twig algorithm.According to this algorithm,the calculation method of the key points on each branch of the wire harness has been given.According to the constructed hierarchical model,the root branch,the firstlevel sub-branches and the second-level sub-branches are sequentially flattened at the interval of the bundle segments which derived from each branch.And the flattening result has been compared with the 2D flattened chart in CATIA.4.The method of determining the 3D and 2D assembly location marks(TIP points and CLAMP points)of the cable harness is proposed.From the clamp point of view,through the model analysis and data processing,the TIP points of the harness are judged by using the holistic method and the individual method.And the method to determine the assembly location mark from 3D harness to 2D harness is studied.The assembly location marks are shown on the 3D centerline simulation chart and the 2D flat chart.5.Example application.From the perspective of the requirements of the harness assembly,a platform of aircraft harness assembly location system based on MATLAB GUI has been built,and took the aircraft cable harness as an example for a detailed demonstration.