KUKA C4 robot zero point calibration V4.8 version

The complete zero calibration process includes calibrating the zero point for each axis. KUKAC4 can specify a reference value (for example: 0°) for any axis at the zero point position through the technical auxiliary tool EMD. Because this allows the mechanical position and position of the axis to remain consistent, each axis has a unique angle value. The zero point calibration position of all robots is similar, but not exactly the same. The exact position will also vary between different robots of the same robot model.

Angle value of mechanical zero position:

A1	-20°
A2	-120°
A3	+110°
A4	0°
A5	0°
A6	0°

Zero calibration is performed by determining the mechanical zero point of the axis. In this process, the axis is moved until it reaches the mechanical zero point. This occurs when the probe reaches the deepest point of the measuring groove. Therefore, each axis is equipped with a zero calibration sleeve and a zero calibration mark.

1. EMD (controller) 2. Measuring cylinder 3. Probe 4. Measuring slot 5. Pre-zero calibration mark

Why learn the offset? The robot is subject to static loads due to the weight of the tool fixed to the flange. Due to the inherent elasticity of the materials on the components and gearbox, the position of the unloaded robot will differ compared to the loaded robot. These differences, which amount to several increments, will affect the accuracy of the robot.

"Offset learning" is performed with load. The difference to the first zero calibration (without load) is stored. If the robot is to work with different loads, "offset learning" must be performed for each load. For grippers that grip heavy parts, "offset learning" must be performed for the gripper without the component and with the component. Mastery.logMastery.log The zero calibration offset value file is located on the hard disk in the directory C:KRCROBORLOG and contains the specific data of the zero calibration: 1. Timestamp (date, time) 2. Axis 3. Serial number of the robot 4. Tool number 5. Offset value in degrees (Encoder Difference) 6. Mastery.log Example: Date: 22.03.11 me: 1010Axis 1 Serialno.: 863334 Tool Teaching for Tool No 5 (Encoder Difference: -0.001209)Date: 22.03.11 Time: 1044 ． ． ． ． ． ． Only a robot that has been zeroed with load calibration has the required high accuracy. The offset must therefore be learned for each load case! Prerequisite: The geometry of the tool has been measured and a tool number has therefore been assigned.

(Version 8.3 also has an EMD indicator light.) First zero calibration: Start operation > Zero calibration > EMD > First zero calibration. The robot moves to the pre-zero calibration position. Starting from A1, move each axis one by one so that the zero calibration marks overlap each other.

Remove the protective cap of the measuring cylinder from the selected axis in the window. (The turned-over EMD can be used as a screwdriver.) Screw the EMD onto the measuring cylinder.

The measuring lead is connected to the EMD and to the X32 interface of the robot junction box.

Click Zero Calibration. Press the confirmation switch and the start key (to start forward operation).

When the EMD detects the lowest point of the measuring cutout, the zero calibration position has been reached. The robot stops automatically. The value is stored. The axis disappears from the window. This proves that the axis has been calibrated. Offset learning (with EMD)Offset learning is performed with load. The difference to the initial zero calibration is stored. If the robot is operated with various loads, the offset learning must be performed for each load. For grippers that grip heavy parts, the offset learning must be performed for the gripper without and with the part. Prerequisites•Same ambient conditions as for the initial adjustment (temperature, etc.)•Load is mounted on the robot. •All axes are in the preset position. •No program is selected. •Operating mode T1Always screw the SEMD without the measuring cable onto the measuring cylinder. Only then can the cable be connected to the SEMD. Otherwise the cable can be damaged. When removing the SEMD, the measuring cable of the SEMD must also be removed first. Only then can the SEMD be removed from the measuring cylinder. After zero point calibration, remove the EtherCAT cable from the X32 interface. Otherwise, interference or damage may occur.

1. Select Startup > Adjustment > EMD > Offset Learning from the main menu.

Checking the load zero calibration with offset (with EMD)Application:• Checking the initial adjustment• Restoring the initial adjustment if the initial adjustment is lost (e.g. after replacement or collision). Since the learned offsets are still present after the adjustment is lost, the robot can calculate the initial adjustment. Before checking an axis, the adjustment of all axes with lower numbers must be completed.Prerequisites• The same environmental conditions as for the initial zero calibration (temperature, etc.)• A load is mounted on the robot and the offset has been learned. • All axes are in the pre-zero position. • No program is selected. • Operating mode T1Always screw the EMD without measuring leads to the measuring cylinder. Only then can the leads be connected to the EMD. Otherwise the leads can be damaged. When removing the EMD, the measuring leads of the EMD must also be removed first. Only then can the EMD be removed from the measuring cylinder. After zero calibration, remove the EtherCAT cable from the X32 interface. Otherwise, interference signals or damage can occur. In the main menu, select Start-up > Adjustment > EMD > Load calibration

Adjustment of robot systems with more than 2 additional axes: If the system has more than 8 axes, you must ensure that the measuring leads of the touch probe are connected to the second R if necessary. Checking the zero calibration with offset (with MEMD)1. In the main menu, select Start-up > Adjustment > EMD > Calibration with load > Zero calibration with offset. 2. Enter the tool number. Confirm with Tool OK. A window opens automatically. All axes for which offsets have been learned with this tool are displayed. The axis with the lowest number is selected. 3. Remove the cover from the X32 interface. 4. Connect the EtherCAT cable to X32 and the zero calibration box. 5. Remove the protective cover from the measuring cylinder on the axis selected in the window. 6. Screw the MEMD onto the measuring cylinder. 7. If not already connected, connect the measuring cable to the zero calibration box. 8. Press Check. 9. Press the enabling switch and start. If the MEMD has passed the measuring cutout, the zero calibration position is calculated. The robot stops automatically. The difference with the "Deviation Learning" is displayed. 10. If necessary, use a backup to store the values. The old zero calibration values ​​are then deleted. If you want to restore a lost initial zero calibration, you must save the values. Axes A4, A5 and A6 are mechanically connected. This means: if the value of axis A4 is deleted, the values ​​of axes A5 and A6 are also deleted. If the value of axis A5 is deleted, the value of A6 is also deleted. 11. Remove the MEMD from the measuring cylinder and replace the protective cover. 12. Repeat steps 5 to 11 for all axes to be zeroed. Exception: This does not apply to A6 if A6 has a marking line. 13. Close the window. 14. Only possible if A6 has a marking line: a. Select Start-up > Adjustment > Reference in the main menu. The option window Reference zero point calibration opens automatically. Axis A6 is displayed and selected. b. Press Zero point calibration to restore the lost initial zero point calibration. Axis A6 disappears from the option window. c. Close the window. 15. Remove the EtherCAT cable from the X32 interface and the zero point calibration box. Deleting the zero point of an axis manually The zero point calibration values ​​of individual axes can be deleted. The axis does not move when the zero point of an axis is deleted. 1. In the main menu, select Start-up > Adjustment > Cancel adjustment. A window opens. 2. Select the axis to be de-adjusted. 3. Press Cancel adjustment. The adjustment data of the axis are deleted.