Hardware structure of azimuth servo control system of numerical control welding positioner: the whole system is composed of IPC industrial computer, communication servo motor and communication servo variable frequency driver. The industrial computer is the center of the experimental system, which is used as the controller to complete the servo control of the motor orientation. The servo motor is a permanent magnet synchronous communication servo motor, the rotating shaft motor is 1ft5071-0af71-2-z, the inclined shaft motor is ift5071-0ac71-2-z, the motor has no built-in photoelectric encoder, external high-precision photoelectric coding, its output is a, B two-way 90 phase staggered pulse, the encoder used in the motor type test is two-phase input, and set 4 times frequency. In order to avoid imprecise counting, continuous counting mode is selected.

In this system, PCL-833 is used to record the pulse number of the photoelectric encoder, and then to complete the response of the azimuth information. The output end of the two channel 12 bit D / a output board is directly connected with the given end of the communication servo variable frequency drive frequency converter experiment through the emergency brake control circuit board, serving as the speed and steering control of the motor when it stops and runs.

Disturbance and anti disturbance method of the system: the working condition of the numerical control welding positioner in the industrial field is very complex. The operation of equipment such as communication frequency converter, power and pneumatic equipment is about to be greatly disturbed. The arc is also a severe disturbance source in the welding process. The noise in these complex environments will disturb the input and output channels through electromagnetic, electrostatic induction and grounding circuits. In particular, the signals being checked are relatively weak, and they need to be transmitted over a long distance, so they are more likely to be disturbed.

In the numerical control welding positioner, there are the following disturbance sources:

1) because there are disturbances caused by electrostatic field, high frequency electromagnetic field of insulated ladder and magnetic field in the space, these disturbances will affect the normal operation of computer, the normal counting of counter board and the output of D / A to a certain extent;

2) strong electric disturbance from communication drive equipment. Switch on and off, spark disturbance and motor start will form strong disturbance to computer;

3) disturbance of arc, spatter and noise during welding;

4) disturbance from signal channel. Random disturbance caused by I / O signal transmission line;

5) mutual interference between interface boards;

6) disturbance during start, stop and operation of pneumatic equipment and power equipment.