1.  Introduction

Computerized flat knitting machine is used for knitting woolen sweater, it is the application of electromechanical integration in knitting machinery. Since the advent of the first commercial flat knitting machine in 1975, after more than 20 years of development, the flat knitting machine has reached a relatively complete level and has now become the development direction of flat knitting machines. Compared with ordinary flat knitting machines, computer flat knitting machines have the advantages of a high degree of automation, high production efficiency, convenient pattern change, and easy control of product quality. The wide range of product possibilities is particularly valued by domestic manufacturers. At present, there are two sets of AC servo systems in the domestic flat knitting machine industry, which are used to control the head and shaker on the flat knitting machine. The main servo is used for the machine head drive system, and the shaker servo is used for the needle bed displacement system.

2.  The simple working principle of computer flat knitting machine system

All knitting-related actions (such as needle selection, triangle transformation, density adjustment, yarn guide, needle bed traverse, etc.) are pre-programmed through the computer controller to each actuator (motor, electronic needle selector, Electromagnets, etc.) send action signals to drive the relevant mechanisms and machine parts to achieve the knitting process.

The computerized flat knitting machine can be divided into 8 parts: main control box, operation panel, creel, flat knitting machine head, needle bed, shuttle track, drawbar, and underframe.

a.  Main control box: including the main circuit board of the host PC and the drive board of the servo motor, etc. The memory and control CPU in the control box store the input programs and control the machine according to the input programs, and process various feedback signals. It is the core of the control part.

b. Operation panel: including display and keyboard, used to display control parameters in real-time or used to modify textile programs and textile data through the keyboard, it is a window for human-computer interaction.

c. Yarn stand: used for the introduction of yarn.

d. Flat knitting machine head: It is the most complicated flat knitting machine, including the most control mechanism and the mechanism that directly controls knitting, which is the heart of the flat knitting machine. It mainly includes the yarn guide mechanism, triangle mechanism, textile needle selection mechanism, density control structure, and signal detection mechanism.

e. Needle bed, the reciprocating motion on the needle bed of the machine head completes the weaving of the fabric through needle selection and its lateral movement.

f. Shuttle track: used to guide the yarn guide and yarn feeder.

g. Pull the lever.

h. Underframe.

3.  Zhishan servo parameter setting

Zhishan servo is used on computer flat knitting machine, including 2 parts: the first part drives the main motor (1kW, 1500RPM) to reciprocate on the bed through the belt drive belt head, the second part drives the shaker motor (0.75kW, 3000RPM) The belt drives the ball screw to move the needle plate to check the pattern. At present, the Zhishan servo system has been successfully used in most domestic flat knitting machine manufacturers. The following is the Zhishan servo parameter settings.

Parameter setting description

(1) Main bed parameters

Pr000 = 1 (control mode selection, 1: position control);

Pr003 = 0/1 (motor running direction setting, which can be used to change the motor direction);

Pr004 = 1 (input command pulse frequency denominator, electronic gear ratio denominator);

Pr005 = 1 (input command pulse frequency doubling numerator, electronic gear ratio numerator);

Pr008 = 55 (position loop proportional coefficient);

Pr010 = 2000 (speed loop proportional coefficient);

Pr011 = 78 (speed loop integral coefficient);

Pr054 = 9 (Output frequency division);

(2) Shaker parameters

Pr000 = 1 (control mode selection, 1: position control);

Pr003 = 0/1 (motor running direction setting, which can be used to change the motor direction);

Pr004 = 1 (input command pulse frequency denominator, electronic gear ratio denominator);

Pr005 = 10 (input command pulse frequency doubling numerator, electronic gear ratio numerator);

Pr008 = 55 (position loop proportional coefficient);

Pr010 = 2000 (speed loop proportional coefficient);

Pr011 = 78 (speed loop integral coefficient);

4.  Conclusions

The application of Zhishan GD 2 in 1 series servo in the computerized flat knitting machine has proved that the servo system has the advantages of fast response, accurate positioning, short setting time, and stable operation. After being used by customers, the knitted sweaters and other knitted fabrics woven from the mountain servo system used in the computerized flat knitting machine can meet the requirements, which can effectively improve the production efficiency.