Research And Design Of Servo System For Computerized Flat Knitting Machine

Recently, computerized flat knitting machine was more and more popular in clothing industry, especially in textile countries like China. The famous making countries of computerized flat knitting machine were Germany, Japan, Switzerland and China. The machines that made in China were sold like hot cakes in Southeast Asia because of the high price of imported. The popularity of computerized flat knitting machine was in the initial stage, so in both the domestic and foreign markets were still have a large space to rise. Although the machines were having such large market demand and domestic output of those machines were rising, but in certain key technology and parts such as the main motor servo controller and wave bed servo controller still relied on copy or import from abroad. In order to control the production cost and increase the competitive power, develop out a special servo controller that possess lower cost and independent intellectual property rights for computerized flat knitting machine were the domestic manufacturers’prime aim.Based on the main servo controller of computerized flat knitting machine as an example, this paper introduced a servo controller’s realization designed for computerized flat knitting machine. The main researched work as follow:We discussed the basic theory of the servo control, built the mathematical model of PMSM based on Clark and Park transformation, and researched the principle and realization of space vector pulse width modulation. And we established the control mode of PMSM.According to the functional requirement of computerized flat knitting machine, we designed and realized the hardware system, which used DSP as main processor and used MCU as coprocessor. Meanwhile, including designed and realized of the whole system structure and modules of the circuit.We used the C language designed the main control program and all kinds of interrupt function. It covers the DSP main function, system core interrupt function, and other important parts. Besides, we also introduced the coprocessor software design.The present starting rotor position of PMSM detecting methods relied on accurate current detection circuits or complex modeling and calculation. To avoid these problems, a new method was presented to detect starting rotor position of PMSM. This method was easy to realize. The paper gives detection theory details and realization steps, and analysed the practicality of the method from this design.Finally, we analysed various kinds of measuring data. And we checked the correctness and reliability of the design of this system in experiments. We also experiment on the new method that we presented to detect starting rotor position. And the experimental results indicated that this method can obtained satisfactory result, and made the motor start smoothly.