Research And Design Of Electrical Control System For Industrial Lockstitch Sewing Machine

With the rapid development of textile industry in China,garment manufacturing enterprises have higher and higher demands for the sewing techniques and sewing equipment.At present garment manufacturers urgently need high-performance lockstitch sewing machines.This thesis is to study and design the electrical control system of industrial lockstitch sewing maching.In this paper,the overall structure of the hardware circuit of the electrical control system designed for lockstitch sewing machines is described firstly.Then,based on the performance requirements of the electrical control system,the related circuits in the controller of the electrical control system are designed,which are illustrated in detail.The main control chip is M3062 LFGPFP of Renesas,Japan.HCPL-4504 and IR2136 are used in the power driving circuits of permanent magnet synchronous motor.The power driver IR2101 S is used in the power driving circuit of hybrid stepping motor.In the research and design of this electrical control system,firstly,the structure characteristics and mathematical models of the permanent magnet synchronous motor and hybrid stepping motor are analyzed.Then,based on the control requirements,the control strategies of the permanent magnet synchronous motor and hybrid stepping motor are deeply studied.Finally,the sensorless control strategy based on sliding mode observer(SMO)algorithm is adopted for permanent magnet synchronous motor,and the control strategy based on subdivision control algorithm is adopted for hybrid stepping motor.In the part of software design,C language and assembly language are used,and modular programming method is adopted.Software program includes the main program module,the system power-on initialization subroutine module,humancomputer interaction subroutine module,speed regulation subroutine module,sewing mode control subroutine module and system deceleration brake subroutine module.The designed electric control system has the characteristics of high sewing speed,quick start-stop,good speed stability and accurate positioning.It can realize the functions of automatic needle stop,automatic thread trimming and picking thread,reinforcing sewing,free sewing and combined sewing.Sewing mode and parameters can be set by the man-machine interactive operation panel.The experimental results show that the design of this electrical control system is reasonable,and this system has reliable performance and make the lockstitch sewing machine meet the given requirements of sewing techniques.