KUKA AGILUS-3 troubleshooting

KUKA AGILUS-3 troubleshooting

KUKA KR AGILUS-3 is a series of 6-axis articulated robots designed for small load, high-speed assembly, handling, and inspection scenarios, covering KR 4 R500-3, KR 4 R600-3, KR 7 R700-3, and KR 7 R900-3. This series has a compact structure, high dynamic performance, and the controller is compatible with KR C5 micro. For on-site engineers, the factors that truly affect equipment availability are installation fixation, transportation posture, cable connection, cover lubrication, toothed belt tensioning, Mastering zero calibration, and common troubleshooting. Below is a set of practical maintenance and troubleshooting ideas for this series of models.

Model positioning and core data

KR 4 R500-3 has a rated load of 4 kg, a maximum load of 5.4 kg, a maximum arm span of 500 mm, a working space of approximately 0.25 m ³, a body weight of approximately 21 kg, a repeatability accuracy of ± 0.015 mm, and a protection level of IP54. KR 4 R600-3 has a rated load of 4 kg, a maximum load of 5.2 kg, a maximum arm span of 600 mm, a working space of approximately 0.43 m ³, a weight of approximately 23 kg, a repeatability accuracy of ± 0.015 mm, and a protection level of IP54. KR 7 R700-3 has a rated load of 7 kg, a maximum load of 10.2 kg, a maximum arm span of 703 mm, a workspace of approximately 1.6 m ³, a weight of approximately 29 kg, a repeatability accuracy of ± 0.02 mm, and a protection level of IP67. KR 7 R900-3 has a rated load of 7 kg, a maximum load of 8.8 kg, a maximum arm span of 902 mm, a workspace of approximately 2.7 m ³, a weight of approximately 31 kg, a repeatability accuracy of ± 0.02 mm, and a protection level of IP67.

In terms of axis range, the KR 4 series A1 is ± 170 °, A2 is -195 ° to+40 °, A3 is -115 ° to+150 °, A4 is ± 185 °, A5 is ± 120 °, and A6 is ± 350 °. The speed under rated load is approximately: A1 487 °/s, A2 360 °/s, A3 488 °/s, A4 552 °/s, A5 529 °/s, A6 800 °/s. The KR 7 series A1 has a speed of ± 185 °, A2 ranges from -190 ° to+40 °, A3 ranges from -115 ° to+160 °, A4 has a speed of ± 200 °, A5 has a speed of ± 120 °, and A6 has a speed of ± 350 °. The speed is approximately: A1 450 °/s, A2 380 °/s, A3 525 °/s, A4 580 °/s, A5 541 °/s, A6 832 °/s. The zero position is A1 0 °, A2-90 °, A3 90 °, A4 0 °, A5 0 °, A6 0 °.

The load must be checked for both mass and mass moment of inertia simultaneously. Install flange hole circle 31.5 mm, 7 M5 threads, strength grade 12.9, engagement depth 5.5 to 6 mm, positioning element 5 H7. During normal operation, the KR 4 R50-3 has an axial force of approximately 200 N, a radial force of 147 N, a tilt torque of 14 Nm, and a flange torque of 7 Nm. During emergency stop, it can reach 250 N, 350 N, 34 Nm, and 25 Nm. During normal operation of KR 7 R700-3, the axial force is 377 N, the radial force is 249 N, the tilt torque is 39 Nm, and the flange torque is 15 Nm; during emergency stop, the axial force is 379 N, 465 N, 86 Nm, and 65 Nm. Tool design must consider these loads, not just static weight. If the center of gravity, moment of inertia or additional load of the tool exceeds the load diagram, it will cause overload of the motor and gearbox, which must be negotiated with KUKA.

Safety and Hazardous Area Control

This robot belongs to partially completed machinery and must be integrated into a complete system that complies with the EU Machinery Directive. The risk assessment, safety functions, EC conformity declaration, and CE mark must be completed by the system integrator. Dangerous areas include workspace, mechanical arm stop stroke, and external axis stop stroke. The stopping stroke is equal to the reaction stroke plus the braking stroke. In the stop category, STOP0 means immediately shutting down the drive and braking the brake; STOP1 is braking along the trajectory. Manual mode T1 speed does not exceed 250 mm/s, T2 allows for speeds greater than 250 mm/s. T1 is used for testing, programming, and demonstration purposes; T2 is only used for testing and does not allow teaching or programming. New or modified programs must be tested under T1 first.

If debugging must be carried out within the protected area, personnel and mechanical arms, including tools, should maintain a reference distance of at least 50 cm, which will be determined by risk assessment. The operator under T2 must be located outside the danger zone, and there must be no other personnel inside the protective zone. Automatic mode is only allowed to operate when all protective devices are intact, there is no one in the danger zone, and the workflow is clear. If the robotic arm or external shaft stops for no reason, an emergency stop must be triggered before entering the danger zone.

The power-off operation must follow 5 safety steps: power-off, prevent restart, confirm no power, ground and short circuit, cover or isolate adjacent live parts. Even if the controller is turned off, some components may still carry a voltage of 50 V to 780 V for several minutes. Notify relevant personnel and hang warning signs before starting work. The motor will generate heat during operation, and protective gloves must be worn. Active implant personnel should maintain a distance of at least 300 mm from the motor and brake, applicable in both powered and powered off states. The teaching pendant must be clearly assigned to the corresponding robot, and disconnected teaching pendant or components should be immediately removed from the system. External keyboard and mouse are only allowed to be used during startup or maintenance work, driver shutdown, and when no one is in the danger zone; It must be removed immediately after use. After modifying the robot, the safety level must be rechecked, all safety functions must be tested, and existing programs must be tested under T1 first.

Installation and transportation

The installation methods include base installation and rack installation. The base installation uses C288 mounting base, weighing approximately 15.6 kg, with 4 chemical anchor bolts and 4 M8x30 ISO4017-10.9 hex bolts (KR 4) or 4 M10x35-8.8-A2K hex bolts (KR 7), equipped with conical spring washers. The recommended concrete strength is C20/25, and the foundation surface should be flat and smooth. There should be no insulation layer or mortar layer between the bottom plate and the concrete. The rack installation uses standard rack installation components, using 4 M8x30 ISO4017-10.9 (KR 4) or M10x35-8.8-A2K (KR 7) hex bolts and tapered spring washers, with a tightening torque of 45 Nm. During installation, positioning pins must be used to ensure that the robot falls vertically and avoid damaging the pins.

Transportation positions: KR 4 is at A1 0 °, A2 120 °, A3 149.9 °, A4 0 °, A5 60 °, A6 0 °; KR 7 is at A1 0 °, A2-110 °, A3 156 °, A4 0 °, A5 44 °, A6 0 °. During transportation, rope slings are used to wrap around the pull rod and rotating column to ensure that all edges are long enough and will not damage the robot. Avoid vibration and collision during transportation, otherwise it may cause subtle damage. Before resuming operation, check whether the robot is fixed, whether there is external damage, whether the motor and brake are abnormal, whether the protective device is intact, whether the power supply system is matched, whether the grounding is reliable, whether the plug is locked, and whether there are foreign objects or loose parts.

Additional Load Lifting Attachments are required for wall and ceiling installation, part number 0000-459-988. When installing on the wall, the robot is first fixed to the Load Lifting Attachment, rotated 90 °, then positioned on the wall with a forklift, and finally fixed with M10x35-8.8-A2K hex bolts with a tightening torque of 45 Nm. Ceiling installation is similar, rotated 180 °. After installation, the grounding conductor connection must be reinstalled.

Connecting cables and interfaces

Connecting cables are used to transmit power and signals between the robot controller and the robot. The standard lengths are 1 m, 4 m, 5 m, 7 m, 10 m, 15 m, and 25 m, with a maximum of 25 m and a maximum extension of 1 time. The cross-section of the grounding conductor should be at least 4 mm ². When fixed laying, the bending radius of the motor cable should not be less than 75 mm, and the control cable should not be less than 45 mm. The cable can only be installed indoors, with a temperature range of -10 ℃ to+45 ℃. Motor cables and data cables should be laid separately in metal troughs, and EMC measures should be taken if necessary.

KR C5 micro connection: motor cables XD20.1 and XD20.2 to XD30, interface is Shell Size 20; Data cables XF21 to X31, interface M12 Y-code; Grounding conductor 4 mm ², M4 ring cable terminal. Interface A1 is located at the rear of the chassis, including motor cable connection X30 and data cable connection X31. The interface A1 of KR 4 variant also includes EMD calibration interface X32, AIR1 to AIR4 air circuit connection (outer diameter 4 mm), and user connection X76 (M12, A code, 8 poles). The interface A1 of KR 7 variant also includes MEMD connection X32, PURGE exhaust connection (maximum 0.3 bar, oil-free and waterless, compliant with ISO 8573-1:2010 7:4:4), AIR1 to AIR4, I/O connections X76, X31, X30.

CTR AIR energy supply system: X76 and X96 are M12, A codes, KR 4 is 8-pole, KR 7 is 12 pole. The maximum pressure from AIR1 to AIR4 is 7 bar, and the vacuum is reduced to atmospheric pressure by 0.95 bar. AIR CTR GIG energy supply system: including interfaces X74, X94, X41, X3, X4, etc., supporting CAT5e data cables and valve units. The valve type is a 5/3-way solenoid valve, with a working pressure of 3 to 7 bar, a switching frequency of 10 Hz, M5 thread, and a medium of oil-free dry filtered air. The maximum filtration accuracy is 5 μ m, and the working temperature is+5 ℃ to+45 ℃. The PURGE option is used for compressed air preparation and pressure limitation, with a fixed working pressure of 0.01 MPa (0.1 bar), a gas consumption of 0.1 m ³/h, an input pressure of 0.1 to 1.2 MPa, and an outer diameter of 4 mm for the air circuit connection. PURGE is only for cleaning work and is prohibited during operation to prevent the emission of foreign particles.

Maintenance cycle and cover lubrication

Maintenance interval: Check the fastening bolts, anchor bolt nuts with 80 Nm, and fixing bolts with 45 Nm after 100 hours; check the base fastening torque after 1 year; Lubricate the inside of the cover plate for 5000 hours or at the latest 1 year, and replace the A3 and A5 toothed belts. Before maintenance, it is necessary to ensure that the maintenance point is freely accessible and remove tools and additional equipment that hinder maintenance. Robots must be secured by emergency stop and prevented from unauthorized activation.

KR 4 variant cover plate lubrication: A1 cover plate has 6 M3x8-8.8 hexagon socket bolts, A2 cover plate has 3 M3x12-8.8 bolts, A3 cover plate has 6 M3x8-8.8 bolts, A5 cover plate has 5 M3x8-8.8 bolts. After removing the cover plate, apply Optitemp RB2 grease on the inside with a brush, about 10 g. Tighten the torque to 1.2 Nm during installation. After completion, move A1, A2, A3, A5 to check for abnormalities. KR 7 variant cover lubrication: A2 cover plate with 6 M4x10-8.8 Torx, A3 cover plate with 8 M4x10-8.8 Torx, A5 cover plate with 6 M4x8-8.8 Torx. The lubricating grease is also Optitemp RB2, about 10 g. When installing, tighten the torque to 2.8 Nm. After completion, move A2, A3, A5 to check for abnormalities.

The replacement cycle of the toothed belt is 5000 hours or at the latest 1 year. KR 4 variant A3 toothed belt specification 80-MTS3M-408G, target frequency 165 ± 10 Hz; A5 toothed belt specification 60-MTS3M-255G, target frequency 239-287 Hz. KR 7 variant A5 toothed belt specification 60-MTS3M-330G, target frequency 200 ± 10 Hz. When replacing the A3 toothed belt, first fix the arm, remove the 6 M3x8-8.8 bolts on the A3 cover plate, loosen the 2 M4x12-8.8 bolts, and remove the old belt. After installing the new belt, use the A3 belt tensioning tool and frequency meter to measure. The sensor should be 2 to 3 mm away from the belt, and the frequency should be read by moving the belt side. If the target value is not reached, fine tune the tension screw and repeat the measurement. After reaching, tighten 2 M4x12-12.9 hexagon head bolts with a torque of 2.8 Nm. When controlling the measurement, if tools are used, A3 should not be affected by gravity, for example, if the arm is horizontal and A3 is at+90 ° or -90 °; Any position without tools. Measure the frequencies on both sides and take the average. After completion, calibrate A3 and run the program to check T1.

When replacing the A5 toothed belt, first fix A5, remove 5 M3x8-8.8 bolts from the A5 cover plate, loosen 2 M5x10 hexagon head down bolts and 1 M4x16-8.8 adjustment screw, and remove the old belt. After installing the new belt, gently tighten the adjusting screw to move the pulley in the A4 direction, pre tighten it, and then lightly tighten the 2 M5x10 bolts. Measure with a frequency meter. If the target value is not reached, loosen 2 M5x10 bolts, adjust with adjusting screws, and repeat the measurement. After reaching, tighten 2 M5x10 bolts with a torque of 3.8 Nm (KR 4) or 5.6 Nm (KR 7). When controlling measurements, if tools are used, A5 should not be affected by gravity, for example, if the arm is horizontal and A4 is at+90 ° or -90 °; Any position without tools. Measure the frequencies on both sides and take the average. After completion, calibrate A5 and perform program checks on T1.

Mastering and Zero Calibration

The KR 7 variant can be Mastered using the MEMD tool, A1 to A5 are calibrated using the MEMD Mastering set, and A6 uses standard flat keys and zero calibration tools. Step: Rotate A6 flange to make the flange groove close to the casting Mastering surface; Insert the zero calibration tool to ensure a tight fit with the slot; Slowly rotate the flange to align the flat key with the casting reference surface, completing A6 calibration. If A6 is forcibly rotated, it may damage the components. For a robotic arm with a motor brake release button, the A6 can be manually rotated by pressing the button to bring the zero calibration tool closer to the casting Mastering surface.

Emergency Mastering is suitable for emergency situations without EMD and dial indicators. The KR 4 and KR 7 variants have Mastering markings on each axis. When operating, follow the specified steps to align the engraved lines. If the zero point is lost after using emergency Mastering, the normal operation of the previous program cannot be guaranteed. Therefore, to teach programming in Cartesian coordinate system, EMD or micrometer should be used for Mastering.

Common troubleshooting

Robot unable to enable or emergency stop failure: Check if the teaching pendant is correctly connected and assigned to the corresponding robot, disconnect the device and immediately remove it from the system.

Slipping or abnormal noise of the toothed belt: Check the tensioning frequency of the toothed belt and adjust it according to the target values of A3/A5; Check if the toothed belt teeth are damaged. If damaged, replace them and contact KUKA.

Abnormal noise or wear inside the cover plate: Lubricate the inside of the cover plate every 5000 hours or 1 year, use Optitemp RB2, and pay attention to the tightening torque.

Loose connectors or abnormal communication: Check if motor cables XD20.1/XD20.2 to X30 and data cables XF21 to X31 are securely locked; When the KR C5 motor connector is locked, there should be a clicking sound, and the red ring should not be visible and should be fully inserted.

Grounding abnormality: Check the grounding conductor of 4 mm ², M4 ring cable terminal, M8 hex nut and tapered spring washer, with a tightening torque of 1.6 Nm (KR 4) or 2.8 Nm (KR 7).

IP67 protection failure: check PURGE connection, maximum 0.3 bar, no oil or water; Check if the compressed air is supplied according to ISO 8573-1:2010 7:4:4.

Zero point loss: After replacing the toothed belt, motor, or using the brake release device, it is necessary to re master the relevant shaft.

External axis no feedback: Check XP7.1 and XP8.1, only allow connection of rotary transformers.

Robot accidentally sinks: Check for brake, load, and collision damage. If the robotic arm or external shaft collides with obstacles, mechanical end stops, or shaft limiting devices, it must stop running and contact KUKA.

Abnormal compressed air pressure: Check the pressure regulator, PURGE working pressure 0.01 MPa (0.1 bar), input pressure 0.1 to 1.2 MPa.

Discontinuation, storage, and disposal

Before stopping, move the robot to the transport position, remove tools and accessories, disconnect peripheral connections, motor cables, data cables, and grounding wires. Using a transport hoist or forklift, remove 4 M8x30 ISO4017-10.9 or M10x35-8.8 hex bolts and tapered spring washers, lift vertically to avoid damaging the locating pin. The storage location should be dry, dust-free, avoid temperature fluctuations, wind blowing, ventilation, and condensation, and avoid direct sunlight. Clean the robot, remove foreign objects and rust, install all cover plates and check seals, seal electrical interfaces and hose joints, cover with film and seal on the chassis, and add desiccants if necessary.

When disposing of waste, classify according to materials: cast aluminum parts such as columns and chassis; Casting magnesium alloys such as arms, pull rods, and wrists; Copper cables and core wires; Steel gearbox, bolts, washers; Electrical components such as RDC and EDS are recycled as electrical waste; The motor is scrapped as a whole without disassembly; Plastic parts such as cover plates, cover plates, NBR shaft seals and O-rings, PU hoses, PUR cable sheaths. Auxiliary materials include Loctite 510 surface sealant, Drei Bond 1305/1342/1385/5204HV adhesive and sealant, PETAMO GHY 133 N grease, Harmonic Drive 4B No.2 grease, Sumiplex SFB No.1 grease, and Kl ü beralfa MR 3-500 UV lubricant. Waste disposal should be carried out in accordance with local regulations, and efforts should be made to classify and recycle as much as possible.