Fanuc FANUC robot fails to work normally after sta

2022-08-06
  • Detail
Qb/t 2710 (2) 005 leather physical and mechanical experiment bending strength and elongation

fanuc FANUC robot can not work normally after startup analysis

analysis and processing process: after careful observation and inspection, it is found that when the z-axis of the machine tool moves within a small range (about 2.5mm), the maintenance work of the robot is normal, and the movement is stable without vibration. However, once the above range is exceeded, the machine tool will vibrate violently

according to the analysis of this phenomenon, the position control part of the system and the servo driver itself should have no fault. It is preliminarily determined that the fault is on the position detection device, namely the pulse encoder

considering the semi closed-loop structure of the machine tool, it was confirmed that the fault was caused by the poor pulse encoder through robot maintenance and replacement of the motor during maintenance

in order to deeply understand the root cause of the fault, the following analysis and tests were carried out during maintenance:

1) when the servo driver master divided the new materials into six major circuits such as special metal functional materials, high-end metal structural materials, advanced high molecular materials, new inorganic non-metallic materials, high-performance composite materials and cutting-edge new materials, manually rotate the motor shaft and check the system display, It is found that the actual position value can be correctly displayed on the system robot maintenance display regardless of the forward or reverse rotation of the motor, indicating that the A, B, *a, *b signals of the position encoder are output correctly

2) since the screw pitch of the z-axis lead screw of the machine tool is 5mm, the vibration will occur as long as the z-axis moves about 2mm. Therefore, the fault cause may be related to the actual position of the motor rotor up to point E, that is, the rotor position detection signals C1, C2, C4 and C8 of the pulse encoder are defective

according to the above analysis, considering that the z-axis can normally move about 2.5mm, it is equivalent to the actual rotation of the motor by 180 °?, Therefore, it is further determined that the fault position is that C8 in the rotor position detection signal is defective

according to the same method in the above example, after removing the pulse encoder, add some DC5V recommended by experts to pins n/t and j/k according to the connection requirements of the encoder (see table), rotate the encoder shaft, and measure C1, C2, C4 and C8 with a multimeter. It is found that there is no change in the state of C8, and it is confirmed that the rotor position detection signal C8 of the encoder is faulty

table encoder pin connection table

pin a B C D E F G H j/k l m n/t P R s

signal a B C1 *a *b Z *z shielding +5v C4 C8 0V C2 oh1 oh2

further inspection found that the C8 output robot maintenance drive IC inside the encoder had been damaged; After replacing the integrated circuit, reinstall the encoder and adjust the rotor angle in the same way as in the above example, and the machine tool returns to normal

Copyright © 2011 JIN SHI