Research On Dynamic Performance Of Electronic Shogging System On Warp Knitting Machine

Warp knitting is a common and efficient way of fabric processing method.Warp knitting fabrics are important sources of high-end clothing fabrics and household textile fabrics.The shogging of the guide bar diven by motor is the core movement of warp knitting,which determines the distribution of loops in the warp knitting fabric,thus weaving different patterns.The performance of shogging movement directly determines the pattern grade and performance of warp knitting fabrics,and the shogging time directly determines the maximum running speed of warp knitting machine.Therefore,it is of great significance to study the control technology of electronic shogging system on warp knitting machine.This paper first introduces the development history of warp knitting machine shogging mechanism,then investigates the research status of electronic shogging system on warp knitting machine at home and abroad,and expounds the significance of the research on electronic shogging system on warp knitting machine.This paper analyzes the shogging craft of double needle bar warp knitting machine.Within one circle revolution of the spindle,the shogging motor needs to drive the guide bar to move about4 times at most,and the linkage or cam mechanism on the spindle will drive the guide bar to complete 6 times of swinging.Therefore,the electronic shogging system on warp knitting machine needs to meet the following requirements: high positioning precision,rapid response and high start-stop frequency.Permanent magnet synchronous motor(PMSM)is used as the driving component in most electronic shogging system on warp knitting machines,and its control performance and precision directly affect the performance and precision of the electronic shogging system.This paper briefly describes the basic structure and working principle of PMSM.In the three-phase static coordinate,the motor speed and torque cannot be well controlled.By using the vector coordinate transformation,the mutual coupling AC parameters of can be converted into the excitation and the torque parameter,and the magnetic field and the torque can be controlled respectively.Then the principle of SVPWM is analyzed,and simulation model for the PMSM vector control is bulit.In order to figure out the problem in increasing the running speed of warp knitting machine electronic shogging system,and the oscillation phenomenon at high running speed,the mathematical model of the mechanical load of the electronic shogging system was established.The bandtrap filter is connected in series with the speed loop to suppress the mechanical resonance of the electronic shogging system.A simulation model for the resonance suppression of the electronic shogging system is built and an experiments on the RD7-EL warp knitting machine is implemented.The results shows that increasing the system gain would cause mechanical resonance in the electronic shogging system,which was not conducive to the stability of the system and will cause the guide bar to wipe or strike the needle when passing through the knitting needle.After adding the bandtrap filter,the mechanical resonance phenomenon of the electronic shogging system is well suppressed.In view of the large workload on traditional PI controller parameter adjustment and PI controller is not suitable for situations requiring high motor performance,the model predictive control is applied to the electronic shogging control system on warp knitting machines.The finite set MPC of the motor current and the infinite set MPC of the motor speed is established,and the simulation model of the cascade MPC of the electronic shogging system is built.The results show that the cascade MPC controller has better dynamic response and stronger anti-interference ability than the cascade PI controller.In order to realize the digital control of the warp knitting machine workshop,the overall structure of the electronic shogging system software system is determined.The MC4N-ECAT type controller is selected as the slave controller,and C#.NET is selected as the development language of the host PC software.The host PC software and the slave controller software of the electronic shogging system are designed and optimized.A set of electronic shogging software system for different double needle bar warp knitting machines has been developed.The electronic shogging software system on E22 double needle bar warp knitting machine is upgraded in warp knitting machine workshops in Putian City,Fujian Province,which solves technical difficulties in the electronic shogging system and realize the digital control of the electronic shogging system on the warp knitting machine.