0 Introduction

At present, more than similar devices around the vertical layer (wire spool with close vertical), the device susceptible to interference, stopping frequently, uneven tension wire. Lag angle control based on automatic cable system can improve the accuracy and performance of cable. Through the perspective of the PLC programmable controller closed-loop control, so that wire to a fixed lag angle β in the spool on the high-speed layer around. PLC detects the angle value compared with the set value, the error pulse signal to the PLC sends linear servo motor drive unit movement, the bias tends to zero, in order to achieve a fixed phase angle layer of wire wound. Completed using man-machine interface devices and real-time monitoring of data input. Designed and implemented in the area outside the normal speed for the track, for the rapid catch-up after switching to synchronous speed tracking, wire spool reaches the edge of the delayed again after the formation of a new automated tracking system control cable, the cable system to meet Automatic smooth cable requirements [1] - [2].

A layer around the principle of the process

Automatic spread of the structure shown in Figure 1. Cable uses lag angle cable, servo motor through roller screw and slide the cable device to promote a certain angle cable. In the closing line of the diameter spool area from side to side when the cable, the entire area is divided into general tracking and tracing for the two regions. In general, the regional fixed-lag tracking angle tracking mode, variable-angle region for the tracking mode. As the wire in the edge layer Raozhi spool, it will automatically layer around the opposite direction, in the process, does not allow a forward angle layer around the wire, otherwise there will be gaps between the wire, the next layer of the defects, layer around the will be forced to interrupt. Therefore, to change the angle of detection and control of the region is essential.

Automatic switching by reversing the direction of movement marked the formation of linear units, set the left switch for the right line to sign left-reset flag; switch set to the right for left-flag, reset right-line flag. Take-back line with the rising edge of the switch unit will be around to walk a straight line sign is inverted. The right to change the closing line, for example, when the right moment for action to the switch, linear units to 6 times the base speed fast forward to β ≤ 0; when the main motor to continue rotating, linear unit to the base rate continues to track, when the Welding Wires Manufacturers wound close to work the right-most circle round the word line, the line unit to stop, and reset the unit the right straight line flag, set the left-line flag. Similarly, close to the line in left for the right change to the closing line. Take-left line, angle, center angle + α ≤ maintain lag angle; the right line, angle, center angle α to maintain ≥ - lag angle. For the process to change the angle of the area shown in Figure 2. 

2 control system structure and working principle

2.1 Control System Architecture

Cable device according to cable theory, the control system must first complete real-time detection angle cable. Design uses a 1000-line incremental encoder with the PLC program to achieve the combination of digital cable angle sensor for real-time detection angle, the sensor resolution of 0.09 °, to meet the minimum wire diameter of 0.8mm of the upper perimeter of the spindle angle detection requirements; through the action switches to achieve close to linear unit area normal to the regional and change tracking; output pulse through the PLC control servo motor drive unit to run a straight line [3]. 

2.2 linear unit works

Linear units moving speed should match the spindle speed. Installed on the spindle speed sensor, a measurement of the rotation of the spindle angular velocity N (rev / sec). Spool on the wire along the axis of the moving speed V = N * Φ, where Φ for the Nickel Alloy Welding Wire diameter, the unit mm, V the unit mm / s. In order to maintain the cable wire on the body and the spindle speed of synchronization, that is to maintain a fixed phase angle, linear unit of the advance should be equal to V. To ensure accurate synchronization lag angle, road speed line unit should be equal to the angle loop with the output value V (offset), V into the servo motor speed (pulses / s) to:

Pulse rate = M * N * Φ / d (a / s) (1)

Where, N is the spindle rotation angular velocity (rev / sec), Φ for the wire diameter (mm), M is the servo motor encoder number of lines per circle, d is the lead screw roller (mm / rev) .

According to equation 2-1 servo motor pulse rate of a given formula, the range 0 ~ 25000 P / S, so the MV output saturation limit should be set on a 2500 P / S.