Research On Motor Drive Control System Of Constant Tension Conveyor For Knitting Machine

Knitting machine constant tension yarn feeder in the textile industry is a very important textile equipment,its performance has a serious impact on the quality of textile products.Knitting machine constant tension yarn feeder is mainly composed of the tension detection mechanism,the motor drive unit and the main control system,motor drive unit performance is particularly important.This paper is based on the importance of the internal motor drive unit of the constant tension yarn feeder for the performance of the whole yarn feeder.It focuses on the characteristics of the motor drive part of the knitting machine constant tension yarn feeder,and some of the mainstream motor control algorithms.A suitable control method for the yarn feeder motor is adopted to design a suitable DC brushless motor controller to improve the desired performance of the yarn feeder and then build a constant tension yarn feeder motor drive control Hardware test platform to test the effect of such a drive system solution on tension control.First of all,through the analysis and summarization of the domestic and international constant tension yarn feeder,the whole system of the constant-tensioning machine of the knitting machine is established.The system structure is designed,which mainly includes the power supply circuit,the tension sensor unit,the motor drive Unit,and a master unit based on the STM32 digital processor.Secondly,according to the characteristics of the motor for the yarn feeder,this paper proposes a method of using vector control for brushless DC motor with near-sine wave,which makes the motor torque ripple smaller and lower noise,improving the performance of yarn feeder,Simulink is used to realize this control algorithm,and its feasibility is proved.At the same time,the current loop and speed loop response characteristics are tested on the hardware platform..Then,according to the performance parameters of the brushless DC motor selected in this paper,a motor driver which is suitable for the selected motor parameters of the yarn tension is designed.The DC bus voltage is 24 V,the maximum phase current of 10 A can be supported,The maximum wave of the power supply does not exceed 5% of the output voltage,and there are overcurrent,overvoltage,undervoltage protection.Finally,the brushless DC motor drive and the yarn tension stability is tested,including the power supply power stability test,the MOS tube drive waveform of rising edge and the falling edge of the test,the brushless motor phase current waveform,the speed loop,current loop and tension loop test under different PID parameters,the final results show that the use of vector control for the brushless DC motor with back-EMF close to the sine wave can get a better sine wave phase current,and the experimental response of the speed loop and current loop is good,can respond quickly to the load change,so as to reduce the torque ripple to improve the performance of the yarn feeder.