| The production of braiding fabrics was initially dominated by hand braiding,and most of the fabrics were used in clothing and daily necessities.With the development of industrialization,the automation of production equipment increased and the production increased.Because of the special mechanical properties of braiding fabrics,braiding products are used m ore and more widely as composite material preforms in the fields of aerospace,biomedicine,and automobile manufacturing.The technology of controlling a rotary braiding machine to realize the production of various types of special-shaped cross-section fabrics was studied in combination with modern computer technology,which shortens the design and development cycle of special-shaped cross-section fabrics and improves the production efficiency.The main research contents include:Firstly,the characteristics of multifunction braiding and the arrangement sequence of carriers during braiding were analyzed,which further improves the method of preventing interference of carriers.By establishing a multi-track interleaving model,the constraint conditions that t he number of slots of the closed-loop track should meet were studied,and a method of expressing track information with an adjacency matrix was proposed.The corresponding program was developed to read the adjacency matrix to automatically verify the ratio nality of carriers’ trajectory,and to prompt the carriers’ interference position,which greatly improved the efficiency of special-shaped cross-section fabric track design and carriers arrangement.Secondly,based on the principle of anti-interference of carriers,two design methods of the carrier running trajectory of the special-shaped cross-section fabric were proposed.For the special-shaped fixed cross-section and variable cross-section fabrics,the control strategies of switch cams were studied respectively,and the state matrix of switch cams was obtained.A mathematical model of the transfer law of carriers was constructed,and the B-spline curve was used to fit the space coordinate points of the yarn,and the 3D simulation of the special-shaped cross-section fabric was carried out.Thirdly,in order to verify the feasibility of the design of the trajectory of special-shaped fabric carriers,the software and hardware design of the control system of the multifunction braiding prototype was carried out.The system mainly processes the state matrix of switch cams which are pre-calculated by MATLAB software to control switch cams to switch in a reasonable time sequence.Among them,the hardware system main control unit adopts STM32 chip,and sends instructions to PCA9685(multi-channel pulse width modulation signal generation chip)through IIC bus to control the rotation of servo motor.The software part is transplanted with μC/OS-Ⅲ embedded real-time operating system,and the program of each module of the system is completed.In order to facilitate the use of users,the upper computer software was designed,which can be used for the selection of fabric types and the debugging of the machine.Finally,the conditions of continuous operation of the braiding m achine during variable cross-section braiding and the relationship between braiding velocity and take-off velocity were analyzed.The fabric was braided to verify the correctness of carriers’ trajectory design theory and the feasibility of the control system. |
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