Troubleshooting and Maintenance of KUKA KR AGILUS sixx

Installation, debugging, safe stopping, and troubleshooting of KUKA KR AGILUS sixx six axis robot

Why does the operation and maintenance of KR AGILUS sixx require a "system level" approach

KUKA KR AGILUS sixx is a compact six axis articulated robot, with common models including KR 6 R700 sixx, KR 6 R900 sixx, KR 10 R900 sixx, KR 10 R1100 sixx, and derived W wall mounted and C ceiling mounted versions. It usually forms a complete system with KR C4 compact controller, smartPAD teaching pendant, connecting cables, end tools, and external shafts. For engineers in the "search for solutions" stage, the real tricky problem is often not the single axis not moving, but the coupling between safe stopping, load configuration, interface cables, foundation installation, toothed belt tension, and controller parameters.

The troubleshooting approach for this type of equipment is similar to replacing the shutdown control module or troubleshooting the safety system: first confirm the model and variant, then check the interface, load, safety function, and verification process, and finally conduct low-speed trial operation in T1 mode, gradually scaling up to automatic mode. Any jumping step may cause the stopping distance to exceed the standard, the axis to sag, communication interruption, and even personal injury.

First identify the model and system boundary

The KR AGLUS sixx product family covers load ranges of 6 kg and 10 kg. The KR 6 series includes R700 and R900; The KR 10 series includes R900 and R1100. W represents wall installation, C represents ceiling installation. The controller is KR C4 compact, and the conversion name varies depending on the model, such as KR6R700 C4SR FLR, KR6R700 C4SR WLL, KR6R700 C4SR CLG, etc. The system boundary includes the robotic arm, control cabinet smartPAD、 Connect cables, software, options, and accessories.

The robotic arm is a 6-axis articulated arm with a lightweight alloy casting structure. Each axis is equipped with a brake, and the motor and current carrying cable are arranged under the cover plate, with a protection level of IP54. The wrist is a three-axis coaxial wrist, integrated with 5/2 solenoid valve and CAT5 data cable, which can control tools. The main motion chain consists of A1 rotating column, A2 connecting rod, A3 arm, and A4-A6 wrist. The A1 interface is located at the rear of the base and serves as a critical entry point for motor cables, data cables, external shafts, and air circuits.

Key technical data: must be verified before selection and replacement

1. Axis range and speed

KR 6 series software restriction range: A1 ± 170 °, A2+45 ° to -190 °, A3+156 ° to -120 °, A4 ± 185 °, A5 ± 120 °, A6 ± 350 °. Under rated load, the speed is approximately 360 °/s for A1, 300 °/s for A2, 360 °/s for A3, 381 °/s for A4, 388 °/s for A5, and 615 °/s for A6.

The KR 10 series has slightly lower speeds: A1 is about 300 °/s, A2 is about 225 °/s, A3 is about 225 °/s, A4 is about 381 °/s, A5 is about 311 °/s, A6 is about 492 °/s. When replacing or modifying, if the speed, inertia, and stopping distance do not match, the safety circuit must be re evaluated.

2. Load and center of gravity

The KR 6 series has a rated load of 3 kg, a maximum load of 6 kg, and a load center of gravity of Lxy 60 mm and Lz 80 mm. The KR 10 series commonly has a maximum load of 10 kg. The total additional load installed on the robot must not exceed the maximum total load. Mass inertia needs to be verified using KUKA. Load, and load data must be written into the controller. The flange is 31.5 mm, with 7 M5 screws, a strength of 12.9, and a meshing depth of 5.5 to 7 mm. The deviation of the tool center of gravity will directly change the stopping distance and the service life of the gearbox.

3. Basic load and environment

The basic load includes vertical force, horizontal force, overturning moment, and torque. Taking KR 6 as an example, the normal vertical force is about 967 N, with a maximum of 1297 N; the normal horizontal force is about 1223 N, with a maximum of 1362 N; the normal overturning moment is about 788 Nm, with a maximum of 1152 Nm; the normal torque is about 367 Nm, with a maximum of 880 Nm. The KR 6 R700 robot weighs about 50 kg, the R900 weighs about 52 kg, and the KR 10 weighs about 52 to 55 kg. The installation foundation must be able to withstand the maximum load and cannot use normal load as a safety margin.

Working environment: Operating temperature+5 ° C to+45 ° C, no condensation is allowed; Storage and transportation -40 ° C to+60 ° C; relative humidity ≤ 90%; For altitudes above 1000 meters, a 5%/1000 meter derating is required. These conditions directly affect the motor temperature, brake life, and stopping distance.

Installation and transportation: from transportation location to foot torque

Before transportation, the robot must be placed in the transportation position: A1 0 °, A2-105 °, A3+156 °, A4 0 °, A5+120 °, A6 0 °. During transportation, use a sling to wrap around the connecting rod and rotating column, and other lifting methods are prohibited. Before the robot is fixed, it must maintain its transport position to avoid tilting due to center of gravity deviation.

The installation methods are divided into foot installation, machine frame installation, wall installation, and roof installation. The foundation installation adopts leveling pads, resin anchor bolts, and leveling compounds. The recommended concrete strength is C20/25, and there should be no insulation layer or mortar layer between the foundation and the pad. The torque of the M10x35 anchor bolt is 45 Nm. After running for 100 hours, it needs to be tightened again and checked once a year thereafter. The machine frame installation uses positioning pins and M10x35 bolts with the same torque of 45 Nm. Wall and top installations require load lifting attachments, with M12x30 hex screws having a torque of 40 Nm and M10x35 hex bolts having a final torque of 45 Nm.

After installation, it is necessary to connect the motor cable X30, data cable X31, grounding conductor, and check the equipotential connection. The connector should be locked with a "click" sound and the red ring should be fully inserted. The grounding conductor must be connected with low resistance and comply with EN 60204-1.

Interfaces and cables: high-risk areas for troubleshooting

Robot side interface A1 includes: X30 motor cable, X31 data cable, XPN1 CAT5 data cable, XP7.1/XP8.1 external axis, AIR1/AIR2 air circuit, X41 customer interface, XPN41, etc. Wrist interface A4 includes X41, XPN41, and pneumatic circuits. The standard cable length is 4 meters, with options of 1 meter, 7 meters, 15 meters, and 25 meters, and the maximum should not exceed 25 meters. The fixed bending radius of motor cables should not be less than 50 mm, and the control cables should not be less than 30 mm. Motor cables and data cables should be laid separately, and metal cable trays should be used if necessary to ensure EMC.

Common communication faults are often related to the following: X21/X31 plug not locked; CAT5 cable XPN1 is pulled; The cable and power line are running in parallel for too long; Poor grounding; External axis XP7.1/XP8.1 only connected to a rotary transformer but mistakenly connected to other signals; Abnormal pressure or inadequate filtration in the AIR1/AIR2 air circuit. The X41 customer interface provides 2 digital outputs, 6 digital inputs, and a 24 V/3 A power supply. A 3 A fuse must be added downstream. Valve islands DO7 to DO12 drive 5/2 solenoid valves, and the output does not prevent short circuits. Special attention should be paid when wiring.

Safe stop: STOP 0, STOP 1 and stop distance

The core of troubleshooting security systems is to stop categories. STOP 0: The driver is immediately powered off, the brake is engaged, and the robot brakes in the direction of the path. STOP 1: The robot first maintains braking along the path, and after about 1 second, the power is cut off and the brake is applied. STOP 2: Normal braking, without power interruption or brake holding. Stopping distance=Reaction distance+Braking distance, which is part of the danger zone.

The technical data provides a reference value for STOP 0. For example, KR 6 R700 sixx: A1 stops at a distance of about 133.67 ° for 0.494 s; A2 stops at a distance of about 122.43 ° for 0.556 s; A3 stops at a distance of about 79.29 ° for 0.371 s. KR 6 R700 W: A1 stops at a distance of about 182.04 ° for 0.665 s; A2 stops at a distance of about 68.31 ° for 0.377 s; A3 stops at a distance of about 63.48 ° for 0.379 s. KR 6 R900: A1 stops at a distance of about 113.59 ° for 0.507 s; A2 stops at a distance of about 126.76 ° for 0.684 s; A3 stops at a distance of about 68.10 ° for 0.370 s. KR 6 R900 W: A1 stops at a distance of about 163.11 ° for 0.745 s; A2 stops at a distance of about 67.78 ° for 0.404 s; A3 stops at a distance of about S. KR 10 R900/R1100: A1 is about 106.21 °, 0.536 s; A2 is about 96.06 °, 0.647 s; A3 is about 46.99 °, 0.373 s.

These values are subject to load POV、 Extension distance and brake wear effects. It is recommended to check the stopping distance once a year, especially for high-frequency STOP 0 applications. If the stopping distance significantly increases, check the brake, load configuration, toothed belt tension, safety circuit, and STOP category settings.

Debugging and load verification: T1 mode is the bottom line

After the first debugging or replacement of components, functional testing must be completed: the robot is firmly installed, without external damage or foreign objects, the safety equipment is complete, the power level matches, the grounding and equipotential are correct, and the connector is locked. Then test all safety functions in T1 manual deceleration mode, and then test the program. New or modified programs must be T1 first and then automated.

The load configuration must be input into the controller, including tool mass, center of gravity, and inertia. If additional loads are used, it should be noted that A1 and A2 additional loads are not included in the calculation of basic loads, but must be included in the total load. If tools, fixtures, air pipes, and valve islands exceed the allowable range, they will accelerate wear and change stopping performance.

Maintenance plan: lubrication, toothed belt and cleaning

Maintenance is divided into daily, 100 hour, and annual maintenance. After 100 hours, check the torque of the 4 anchor bolts to 45 Nm; thereafter, check annually. A2 and A3 cover plates need to be coated with Optitemp RB 2 grease inside. A5 and A6 toothed belts must be replaced in pairs, and the tension should be measured after replacement. IW 6 R700 uses AT3/267 toothed belt with a frequency of 305 ± 5 Hz; IW 6/10 R900 and IW10 R1100 use AT3/351 with a frequency of 205 ± 5 Hz. M4 screw torque is 1.9 Nm, M3 screw torque is 0.8 Nm.

When cleaning, only use neutral water-soluble cleaning agents. Flammable, highly corrosive, steam, and high-pressure cleaning are prohibited. After cleaning, thoroughly remove any residue, check for corrosion, and apply rust prevention. During maintenance or repair, the power must be turned off and locked, and emergency stop must remain effective; If it is necessary to be electrified, only T1 mode can be used and safety measures can be added.

Common troubleshooting tree

1. Unable to enable: Check if the safety door, emergency stop, and KCP/smartPAD are uniquely assigned; Check X21/X31 data cables; Check the X20/X30 motor cables; Check grounding and equipotential; Check the diagnostic information of the controller.

2. Increase stopping distance: Check brake wear, whether the load exceeds the limit, whether the POV is too high, extension distance, toothed belt tension, and STOP 0/1 configuration. If necessary, re measure the stopping distance.

3. Abnormal shaft noise or shaking: Check the tension of the toothed belt, lubrication of the cover plate, gearbox, motor, and foundation bolts. If a collision occurs, it is necessary to check the motor and balance system, as there may be invisible damage.

4. Communication interruption: Check CAT5 XPN1, X21/X31, shielding and grounding, cable bending radius, and spacing between power and data lines. If necessary, redo the EMC wiring.

5. Abnormal air circuit: Check the pressure, filtration accuracy, valve island DO7-DO12, X41 power supply and fuse of AIR1/AIR2. The gas source needs to be oil-free, dry, filtered, and comply with ISO 8573.1.

6. Wall mounted/roof mounted sagging: Check the transportation position, load lifting accessories, M12x30 and M10x35 torque, positioning pins, and foundation bearing capacity.

7. Motor overheating: Check the ambient temperature, altitude derating, duty cycle, load, brake release, fan and heat dissipation.

Engineering method similar to the replacement of discontinued modules

If you need to replace old components or discontinued modules, don't just look at their appearance. The steps should be: confirm the robot model and variant; Confirm controller KR C4 compact and conversion name; Verify interfaces X30/X31/XPN1/X41; Check the load diagram and mass inertia; Verify the stopping distance and safety category; Check the specifications and tension frequency of the toothed belt; Verify installation torque and foundation load; Configure input and output in WorkVisual; Finally, verify all security functions in T1 mode. Only when all pass can it be put into automatic mode.

Retirement, storage, and disposal

When retiring, first move the robot to the transportation position, cut off the power, unplug the motor and data cable, remove the grounding, install the lifting equipment, remove the anchor bolts, and lift it vertically. The storage environment should be dry, dust-free, away from sunlight and condensation, with a temperature that meets regulations, covered with dust-proof film, and dried with desiccant. During disposal, materials are classified as follows: cast aluminum, copper, steel, electronic components, motors, plastics, and lubricating grease. Electronic components and motors should not be disassembled and should be treated as electrical scrap.