Whether it is an industrial robot or a household robot, it will always encounter a problem after being used for a long time - joint failure: stuck, abnormal noise, reduced accuracy, unable to rotate... When many people encounter these problems, their first reaction is to find professional operation and maintenance personnel, which is not only time-consuming and labor-intensive, but also has to pay high maintenance costs. Especially small businesses and ordinary users often fall into the embarrassment of "small faults cost a lot."
In fact, most common faults in robot joints do not require professional tools or deep technical skills. As long as they master simple troubleshooting methods, novices can quickly find the cause of the fault and even solve it by themselves, saving time and maintenance costs.
We have talked about the operation and maintenance of joints and pit avoidance skills before, but we have never talked about specific troubleshooting practices. Today, we will focus entirely on robot joints. We will not talk about theory, parameters, or trends. We will only focus on the most common 6 joint faults and dismantle "fault symptoms → troubleshooting steps → solutions."
1. The joints are stuck and inflexible, and there is resistance to rotation.
[Common Scenarios] Home sweeping robots are stuck in walking, industrial robot arm joints are not rotating smoothly, and escort robot arms cannot bend flexibly.
[Troubleshooting steps]
1. Basic inspection: First cut off the power and stop the machine, gently rotate the joint by hand, feel the resistance, and observe whether there are foreign objects (hair, dust, oil) entangled on the surface of the joint, especially home robot joints, which are prone to entanglement with hair and lint.
2. In-depth investigation: If there is foreign matter, clean it and then rotate the joint to see if it recovers; if there is no foreign matter, check the lubrication of the joint and observe whether there is lubricating oil seeping out of the joint gap or whether there is a dry feeling. It is most likely that the lubricating oil has been exhausted or deteriorated.
3. Advanced troubleshooting: If the lubrication is normal but still stuck, check the transmission components (gears, bearings) of the joint to see if there is wear, deformation, or loose components. For example, the gear meshing gap is too large and the bearings are loose, which will cause the rotation to get stuck.
【Solution】
1. Foreign objects entangled: Use tweezers and brushes to clean foreign objects on the joint surface and gaps. The home robot can disassemble the joint shell (simple model) to clean the internal entangled objects to avoid component damage caused by forced rotation.
2. Insufficient lubrication: Add the appropriate type of lubricant (industrial gear oil for industrial joints, special light lubricant for household joints), drop it into the joint gap, and gently rotate the joint to allow the lubricant to evenly cover it to avoid excessive addition that may cause oil accumulation.
3. Part wear: If the gears and bearings are slightly worn, the position of the parts can be adjusted and the loose parts can be tightened; if the wear is serious, the corresponding parts need to be replaced (original parts are preferred, novices can contact the manufacturer for guidance on replacement).
2. There are abnormal noises when the joints are running (squeaking, friction, knocking)
[Common Scenarios] Industrial robot arms make squeaking and friction sounds when running, household robot joints make knocking sounds when they rotate, and precision robot joints make slight abnormal noises.
[Troubleshooting steps]
1. Abnormal noise locating: Start the robot and run it, carefully identify the source of the abnormal noise, determine which joint is making the noise, then cut off the power and stop the robot, and check the joint in a targeted manner.
2. Classification troubleshooting:
- Squeaking and friction sound: It is most likely caused by insufficient lubrication or foreign matter friction on the joint surface. Follow the basic inspection method of fault 1 to clean the foreign matter and check the lubrication.
- Knocking sound: This is mostly caused by loose transmission parts inside the joint (loose gears and bearings), or poor meshing after parts are worn. Turn the joint by hand to feel whether there is a sense of jamming or looseness, and observe whether the parts are offset.
- Slight abnormal noise (precision joints): It may be caused by accuracy deviation or foreign matter entering the joint (dust, small particles). Careful cleaning is required to calibrate the accuracy.
【Solution】
1. Abnormal friction noise: Clean foreign matter and add lubricating oil. If there are scratches on the joint surface, lightly polish it to smooth it (to avoid affecting accuracy).
2. Abnormal knocking noise: Tighten the loose parts inside the joint, adjust the gear meshing clearance, and if the parts are seriously worn, replace the corresponding parts.
3. Abnormal noise in precision joints: Use special cleaning agent to clean the inside of the joint and calibrate the joint accuracy. If there is still abnormal noise, it is recommended to contact a professional for testing to avoid disassembling and damaging the accuracy.
3. The joint accuracy decreases and the movement deviation becomes larger.
[Common scenarios] Precision manipulators have larger grasping and assembly deviations, medical robots have insufficient joint movement accuracy, and household robots have inaccurate positioning.
[Troubleshooting steps]
1. Environmental check: Check the robot's operating environment to see if there are vibrations and temperature abnormalities (high temperature, low temperature). Environmental vibrations and temperature changes will affect joint accuracy.
2. Joint inspection: Check whether the joints are loose and worn, especially the positioning parts of the joints (encoders), whether they are covered with dust and have poor contact. Encoder failure is a common cause of decreased accuracy.
3. Calibration check: Confirm whether the joint needs to be recalibrated. After long-term operation, the accuracy of the joint will naturally shift, especially for industrial joints that operate at high frequencies.
【Solution】
1. Environmental adjustment: Move the robot to a vibration-free and temperature-friendly environment to avoid high temperature, low temperature, and humid environments from affecting joint performance.
2. Component inspection: Clean the dust on the surface of the encoder and tighten loose joint parts. If the encoder fails, replace the encoder and recalibrate.
3. Accuracy calibration: According to the robot manual, perform precision calibration of the joints. Industrial joints can use professional calibration tools, and household and simple industrial joints can be calibrated manually (refer to the manual steps).
4. The joint cannot rotate and is completely stuck.
[Common Scenario] After the robot is turned on, a certain joint cannot rotate. Forcibly starting the robot will cause abnormal noises, errors, or even burning of the motor.
[Troubleshooting steps]
1. Emergency treatment: Cut off the power immediately and do not force start to avoid burning the motor or damaging joint parts.
2. Foreign body inspection: Check the surface and interior of the joint to see if there are any large foreign bodies stuck (such as metal scraps in industrial settings, toys in household settings, and hair balls).
3. Component inspection: If there are no foreign objects, check the transmission components of the joint to see if the gear is stuck, the bearing is damaged, or the connection between the motor and the joint is loose or broken.
【Solution】
1. Foreign matter stuck: Clean large foreign matter. If foreign matter is stuck inside the joint, disassemble the joint shell (simple model) and clean it to avoid violent disassembly.
2. Component failure: If the gear is stuck or the bearing is damaged, the corresponding parts need to be replaced; if the connection between the motor and the joint is loose, tighten the connection part; if the connection part is broken, professionals need to repair or replace the joint assembly.
3. Note: If it still cannot rotate after self-checking, do not force the operation. Contact the robot manufacturer or professional operation and maintenance personnel to avoid expanding the fault.
5. Joint seal failure, water and dust entering
[Common scenarios] Water enters the joints of outdoor inspection robots, oil enters the joints of industrial workshops, and dust enters the joints of household robots, leading to joint failure.
[Troubleshooting steps]
1. Appearance inspection: Observe the seals (sealing ring, sealing cover) of the joint shell to see if they are damaged, aged, or falling off. Damage to the seals is the main cause of water and dust ingress.
2. Internal inspection: Disassemble the joint shell (simple model), observe whether there is accumulation of water, dust, and oil inside to determine the severity of seal failure.
【Solution】
1. Mild failure: Clean the accumulated water, dust, and oil inside the joint, replace the damaged sealing ring and sealing cover, and apply sealant to enhance the sealing effect.
2. Severe failure: If the internal parts of the joint (motor, encoder) have been damaged by water or oil, the damaged parts must be repaired or replaced first, and then the seals must be replaced and sealed.
3. Preventive measures: For robots in outdoor and industrial complex scenes, check joint seals regularly and replace the sealing ring every 3-6 month to avoid seal failure.
6. The joints are severely heated and the temperature is too high during operation.
[Common Scenarios] The joints of industrial robot arms become hot after high-frequency operation, the joints of household robots become hot after working for a long time, and even an error occurs and the machine shuts down.
[Troubleshooting steps]
1. Load check: Check whether the joints are overloaded. For example, the load of industrial joints exceeds the rated value, or the joints of household robots are stuck by foreign objects, resulting in excessive load. Overload is a common cause of heat generation.
2. Lubrication check: Check the lubrication condition of joints. Insufficient and deteriorated lubricating oil will cause increased friction of components, generate a large amount of heat, and cause joint heating.
3. Motor check: Check the motor corresponding to the joint to see if it is faulty. Motor failure will cause heat to be transferred to the joint, causing the joint to heat up.
【Solution】
1. Reduce the load: Stop overload operation, adjust the joint load, and make it work within the rated load range. Industrial joints can reduce the workload, and household robots can pause their work and cool down before use.
2. Optimize lubrication: Replace the lubricant with a new adapted model, clean the deteriorated lubricant and oil stains inside the joints, and avoid friction and heat.
3. Motor detection: If the motor heats up severely, shut down the robot and check the motor after cooling. If the motor fails, professionals need to repair or replace the motor.
To troubleshoot joint problems, remember 3 core principles
1. Safety first: No matter what kind of fault is checked, the first step must be to cut off the power and shut down the machine. Do not operate it with power on to avoid electric shock, component damage, or scratches by rotating joints.
2. From the shallower to the deeper: first do basic inspections (foreign objects, lubrication, looseness), and then do in-depth inspections (component wear, motor failure). Beginners should not disassemble the core components of the joint at the beginning to avoid expanding the fault.
3. Act according to your ability: simple faults (foreign matter, insufficient lubrication) can be solved by yourself, complex faults (severe component wear, encoder failure, motor failure), novices should not force disassembly, it is more worry-free and safer to contact professionals.
Mastering these troubleshooting methods can solve most common failures of robot joints and save maintenance costs and time. What difficult problems have you encountered when troubleshooting joint failures? Let’s chat in the comment area and share solutions~
Source: Tuopu Zhixing Robot Reducer
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