Servo Drive in Flat Knitting Machine

· Brief introduction

Computerized flat knitting machine is used to knit woolen sweaters. It is the application of mechatronics in knitting machinery. Compared with ordinary flat knitting machines, computerized flat knitting machines have the advantages of high degree of automation, high production efficiency, convenient pattern change, and easy control of product quality. At present, two sets of AC servo systems are configured in the computer flat knitting machine industry for the control of the head and shaker on the flat knitting machine. The main servo is used for the head drive system, and the shaker servo is used for the needle bed displacement system.

· Working principle of computerized flat knitting system

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

Computerized flat knitting machine structure:

1.Main control box: including the main circuit board of the upper PC and the drive board of the servo motor. The memory in the control box and the control CPU respectively store the programs that have been entered, control the machine according to the entered programs, and process various feedback signals. It is the core of the control part.

2. Operation panel: including display and keyboard, used to display control parameters in real time or used to modify the textile program and textile data through the keyboard.

3. Creel: used for yarn introduction.

4. Knitting machine head: the mechanism that directly controls the knitting, mainly including the yarn guide mechanism, triangle mechanism, textile needle selection mechanism, density control structure and signal detection mechanism.

5. Needle bed: Finish the fabric weaving by selecting the needle and moving it by itself.

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

7. Pull rod

8. Underframe

· Application of STEP servo in computer flat knitting machine

At present, STEP servo system has been successfully used in the world's leading computer flat knitting machine manufacturers, mainly used in:

a) Drive the main motor (1KW, 1500RPM) to reciprocate on the bed through the belt drive

b) Drive the shaker motor (0.75KW, 3000RPM) through the belt to drive the ball screw to move the needle plate to check the pattern.

1. Main bed parameters

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

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

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

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

Pr008 = 55 (position loop proportionality factor);

Pr010 = 2000 (speed loop proportionality factor);

Pr011 = 78 (speed loop integration coefficient);

Pr054 = 9 (output frequency division);

2. Shaker parameters

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

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

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

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

Pr008 = 55 (position loop proportionality factor);

Pr010 = 2000 (speed loop proportionality factor);

Pr011 = 78 (speed loop integration coefficient);

· Conclusion

The application of STEP servo in flat knitting machine proves that this servo system has the advantages of fast response, accurate positioning, short setting time, and stable operation. Knitted fabrics such as woolen sweaters knitted using the STEP servo system in a computerized flat knitting machine can meet the requirements and can effectively improve production efficiency.