Several common industrial robot faults are analyzed and diagnosed in detail, and corresponding solutions are provided for each fault, aiming to provide maintenance personnel and engineers with a comprehensive and practical guide to solve these fault problems efficiently and safely.
PART 1 Introduction
Industrial robots play a vital role in modern manufacturing. They not only improve production efficiency, but also improve the controllability and precision of production processes. However, with the widespread application of these complex devices in industry, related faults and maintenance problems have become increasingly prominent. By analyzing several typical industrial robot fault examples, we can comprehensively solve and understand the common problems in this field. The following fault example analysis mainly involves the following core issues: hardware and data reliability issues, unconventional performance of robots in operation, stability of motors and drive components, accuracy of system initialization and configuration, and performance of robots in different working environments. Through the detailed analysis and processing of some typical fault cases, solutions are provided for manufacturers and relevant personnel of various types of existing maintenance robots to help them improve the actual service life and safety of equipment. At the same time, the fault and its cause are identified from all angles, which essentially accumulates some useful references for other similar fault cases. Whether in the current industrial robot field or in the future smart manufacturing field with healthier development, fault segmentation and source tracing and reliable processing are the most critical items in the incubation of new technologies and the training of smart production.
PART 2 Fault Examples
2.1 Overspeed Alarm In the actual production process, an industrial robot had an overspeed alarm, which seriously affected the production. After a detailed fault analysis, the problem was solved. The following is an introduction to its fault diagnosis and processing process. The robot will automatically output an overspeed alarm and shut down during the task execution. The overspeed alarm may be caused by software parameter adjustment, control system and sensor.
1) Software configuration and system diagnosis. Log in to the control system and check the speed and acceleration parameters. Run the system self-test program to diagnose possible hardware or software faults. The system operation effectiveness and acceleration parameters were set and measured, and there were no abnormalities.
2) Sensor inspection and calibration. Check the speed and position sensors installed on the robot. Use standard tools to calibrate the sensors. Rerun the task to observe whether the overspeed warning still occurs. Result: The speed sensor showed a slight reading error. After recalibration, the problem still exists.
3) Sensor replacement and comprehensive test. Replace the new speed sensor. After replacing the sensor, perform a comprehensive system self-test and parameter calibration again. Run multiple different types of tasks to verify whether the robot has returned to normal. Result: After the new speed sensor was installed and calibrated, the overspeed warning did not appear again.
4) Conclusion and solution. Combining multiple fault diagnosis methods, the main reason for the overspeed phenomenon of this industrial robot is the speed sensor offset failure, so it is necessary to replace and adjust the new speed sensor[.
2.2 Abnormal noise A robot has an abnormal noise failure during operation, resulting in reduced production efficiency in the factory workshop.
1) Preliminary inspection. The preliminary judgment may be mechanical wear or lack of lubrication. Stop the robot and conduct a detailed inspection of mechanical parts (such as joints, gears and bearings). Move the robot arm manually to feel whether there is wear or friction. Result: All joints and gears are normal and lubrication is sufficient. Therefore, this possibility is ruled out.
2) Further inspection: external interference or debris. Check the robot’s surroundings and movement path in detail to see if there are any external objects or debris. Purge and clean all parts of the robot. After inspection and cleaning, no evidence of the source was found, and exogenous factors were excluded.
3) Re-inspection: Uneven load or overload. Check the load settings of the robot arm and tools. Compare the actual load with the recommended load in the robot specification. Run several load test programs to observe whether there are abnormal sounds. Results: During the load test program, the abnormal sound was significantly aggravated, especially under high load.
4) Conclusion and solution. Through detailed on-site tests and analysis, the author believes that the main reason for the abnormal sound of the robot is uneven or excessive load. Solution: Reconfigure the work tasks to ensure that the load is evenly distributed. Adjust the parameter settings of this robot arm and tool to adapt to the actual load. Re-test the system to confirm that the problem has been solved. The above technical means have solved the problem of abnormal sound of the robot, and the equipment can be put into production normally.
2.3 High motor temperature alarm A robot will alarm during the test. The alarm reason is that the motor is overheated. This state is a potential fault state and may affect the safe operation and use of the robot.
1) Preliminary inspection: Cooling system of robot motor. Considering that the problem is that the motor temperature is too high, we focused on checking the cooling system of the motor. Operation steps: Stop the robot, check whether the motor cooling fan is operating normally, and check whether the cooling channel is blocked. Result: The motor cooling fan and cooling channel are normal, and the problem of the cooling system is ruled out.
2) Further check the motor body and driver. Problems with the motor or its driver itself may also be the cause of high temperature. Operation steps: Check whether the motor connection wire is damaged or loose, detect the surface temperature of the motor, and use an oscilloscope to check the current and voltage waveforms output by the motor driver. Result: It was found that the current waveform output by the motor driver was unstable.
3) Conclusion and solution. After a series of diagnostic steps, we determined the cause of the high temperature of the robot motor. Solution: Replace or repair the unstable motor driver. After replacement or repair, retest the system to confirm whether the problem has been solved. After replacement and testing, the robot has resumed normal operation and there is no alarm of motor overtemperature.
2.4 Initialization error problem diagnosis alarm When an industrial robot restarts and initializes, multiple alarm faults occur, and fault diagnosis is required to find the cause of the fault.
1) Check the external safety signal. It is initially suspected that it is related to the abnormal external safety signal. Enter the “put into operation” mode to determine whether there is a problem with the robot’s external safety circuit. The robot is running in the “on” mode, but the operator still cannot remove the warning light, eliminating the problem of safety signal loss.
2) Software and driver check. Check whether the robot’s control software has been updated or missing files. Check all drivers, including motor and sensor drivers. It is found that the software and drivers are all up to date and there are no missing files, so it is determined that this is not the problem.
3) Determine that the fault comes from the robot’s own control system. Select Put into operation → After-sales service → Put into operation mode in the main menu of the teach pendant. Check the alarm information again. Turn on the power of the robot. Since the function has not returned to normal, it can be determined that the robot itself has a fault.
4) Cable and connector check. Check all cables and connectors connected to the robot. Make sure there is no damage or looseness. All cables and connectors are intact, and the fault is not here.
5) Check the CCU board. According to the alarm prompt, find the SYS-X48 interface on the CCU board. Observe the CCU board status light. It was found that the CCU board status light displayed abnormally, and it was determined that the CCU board was damaged. 6) Conclusion and solution. After the above 5 steps, it was determined that the problem was on the CCU board. The solution was to replace the damaged CCU board. After the CCU board was replaced, this robot system could be used normally, and the initial error alarm was lifted.
2.5 Revolution counter data loss After the device was turned on, a robot operator displayed “SMB serial port measurement board backup battery has been lost, robot revolution counter data is lost” and could not use the teach pendant. Human factors such as operating errors or human interference are usually common causes of complex system failures.
1) Communication before fault analysis. Ask whether the robot system has been repaired recently, whether other maintenance personnel or operators have been replaced, and whether abnormal operations and debugging have been performed.
2) Check the system’s operation records and logs to find any activities that are inconsistent with the normal operating mode. No obvious operating errors or human interference were found.
3) Circuit board or hardware failure. Analysis of the cause: Because it involves the “SMB serial port measurement board”, this is usually directly related to the hardware circuit. Disconnect the power supply and follow all safety procedures. Open the robot control cabinet and check the SMB serial port measurement board and other related circuits. Use a test tool to check circuit connectivity and integrity. Check for obvious physical damage, such as burning, breaking or other abnormalities. After detailed inspection, the circuit board and related hardware appear to be normal, with no obvious physical damage or connection problems. The possibility of circuit board or hardware failure is low.
4) Backup battery problem. Since the above two aspects appear normal, consider other possibilities. The teach pendant clearly mentions that “the backup battery is lost”, which becomes the next focus. Locate the specific location of the backup battery on the control cabinet or robot. Check the battery voltage. Check whether the battery interface and connection are intact. It was found that the backup battery voltage was significantly lower than the normal level, and there was almost no remaining power. The failure is likely caused by the failure of the backup battery.
5) Solution. Purchase a new battery of the same model and specification as the original battery and replace it according to the manufacturer’s instructions. After replacing the battery, perform system initialization and calibration according to the manufacturer’s instructions to recover lost or damaged data. After replacing the battery and initialization, perform a comprehensive system test to ensure that the problem has been resolved.
6) After detailed analysis and inspection, the initially suspected operational errors and circuit board or hardware failures were ruled out, and it was ultimately determined that the problem was caused by a failed backup battery. By replacing the backup battery and reinitializing and calibrating the system, the robot has resumed normal operation.
PART 3 Daily Maintenance Recommendations
Daily maintenance is the key to ensuring the stable operation of industrial robots, and the following points should be achieved. (1) Regular cleaning and lubrication Regularly check the key components of the industrial robot, remove dust and foreign matter, and lubricate to ensure the normal operation of the components.
(2) Sensor calibration Regularly calibrate the robot’s sensors to ensure that they accurately acquire and feedback data to ensure precise movement and operation.
(3) Check fastening bolts and connectors Check whether the robot’s bolts and connectors are loose and tighten them in time to avoid mechanical vibration and instability.
(4) Cable inspection Regularly check the cable for wear, cracks or disconnection to ensure the stability of signal and power transmission.
(5) Spare parts inventory Maintain a certain number of key spare parts so that faulty parts can be replaced in time in an emergency to reduce downtime.
PART 4 Conclusion
In order to diagnose and locate faults, the common faults of industrial robots are divided into hardware faults, software faults and common fault types of robots. The common faults of each part of the industrial robot and the solutions and precautions are summarized. Through the detailed summary of classification, we can better understand the most common fault types of industrial robots at present, so that we can quickly diagnose and locate the cause of the fault when a fault occurs, and better maintain it. With the development of industry towards automation and intelligence, industrial robots will become more and more important. Learning and summarizing are very important for continuously improving the ability and speed of problem solving to adapt to the changing environment. I hope that this article will have a certain reference significance for relevant practitioners in the field of industrial robots, so as to promote the development of industrial robots and better serve the manufacturing industry.
Post time: Nov-29-2024
