iRCalibration Frame Set, formerly CellCal, is a calibration option that compensates for frame changes by establishing a MASTER frame that runs a frame search teach pendant program. After the frame is changed, iRCalibration Frame Set runs the same frame search teach pendant program again and computes the frame offset.
Before you can use iRCalibration Frame Set, you must perform some setup procedures. Setup involves the initial setting of menu options within iRCalibration Frame Set software.
Table 1. iRCalibration Frame Set Detection Schedule Description
ITEM | DESCRIPTION |
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Sensor Type Values: TOS Wrist, I/O, TOS ALL AXES Default: TOS ALL AXES |
This item indicates the kind of sensor used for contact detection. The modes are:
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Detection Port Values: RDI, DI, WDI, WSI, AIN |
This item indicates the desired input port type. The port type that you specify is followed by the desired port number that will go from OFF to ON when contact is detected. The WDI and WSI ports are typically used for arc welding. You will set this item up if you selected I/O as the Sensor Type. You do not need to set this up if you selected TOS Wrist or TOS All Axes as the Sensor Type. The port types are:
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Sensor Enable Values: RDO, DOUT, WDO, or WSO Default: RDO |
This item indicates the I/O sensor enable
digital output port type. The port types are:
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Detection Speed Units: mm/sec Range: 1.0 - 100 Default: 10 |
This item is the search speed for contact detection. This speed is used for both TOS and I/O searches. The value can be increased if cycle time is of great concern (although increasing the speed will also affect the resultant accuracy and repeatability) , or reduced if vibration or other disturbances cause iRCalibration Frame Set to retry excessively. |
Detection Distance Units: mm Range: 1 - 1000 Default: 50 |
This item is the maximum distance that the robot will move while looking for the signal. If no contact is detected within the distance, an error will be posted. |
Return Speed Units: mm/sec Range: 5 - 5000 Default: 50 |
This item is the search return speed. This speed is used for both TOS and I/O searches. |
Return to Start Default: Yes |
When this item is set to YES, the robot will move back to the position before it starts the search motion. This item applies to DETECT POINT instructions only. When this item is set to NO, the robot will move back to a distance specified by the next item (Return distance) |
Return Distance Units: mm Range: 1 - 1000 Default: 50 |
When return to start is set to FALSE, the robot will move back to the distance specified. |
Return term type Default: FINE |
This item is the termination type for return motion. |
Air Cut Speed Units: mm/sec Range: 1 - 1000 Default: 100 |
This item is the non-search motion speed. |
Learn Distance Units: mm Range: 0.5– 20.0 Default: 5.0 |
For “TOS All Axes” method only, there is a short motion before each search to identify dynamic torque values. Learn Distance is the distance in millimeters of this short motion, the direction is determined at the time of the motion. |
Learn Speed Units: mm/sec Range: 0.5 – 50.0 Default: 10.0 |
For “TOS All Axes” method only, this is the speed of the learning motion before each search. |
Sensitivity Tolerance Units: max. motor torque/sec. Range: 1 - 999 Default: 10 |
This item is the primary sensitivity tolerance of TOS Wrist and is not used for TOS All-Axes. It is the rate of change of the disturbance torque. The actual units vary with motor model, gear ratio, and amplifier current, and are affected by tooling length. However, the effect for calibration is largely independent of these factors and a value of 10 is considered normal operation for typical installations. You should not use a value of less than 10 or misdetections might occur. This value can be increased if false detections occur frequently. WarningBe careful when you change this number. Changing the sensitivity tolerance might cause a false detection. This could injure personnel or damage equipment.
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Torque Threshold Units: max. motor torque Range: 1 to 999 Default: 100 |
For TOS All Axes, this item is the only measure of contact detection. During the learning motion a torque level is memorized and that level plus Torque Threshold must be exceeded for contact to be determined. If false detections are being experienced then this value should be increased. For TOS Wrist, this item is the level of disturbance torque that is used as another means for contact detection. The default value of 100 is considered normal operation for typical installations. If increasing the value of Sensitivity Tolerance does not make false detections disappear, then this value should be increased until the false detections disappear; then, reset the value of Sensitivity Tolerance . |
Fit Tolerance Units: mm Range: 0.1 - 100 Default: 0.5 |
For Detect Circle instruction: The robot detects 4 points inside the circle and the calibration software will fit a circle to the 4 detected positions. The fit error is defined as the maximum distance from the 4 points to the circle. If the fitting error exceeds the tolerance, the calibration software will post an error. |
Radius Tolerance Units: mm Range: 0.1— 100 Default: 0.5 |
The Detect Circle instruction stores the circle's radius during mastering. At run time, if the computed circle radius differs from the stored radius value and difference exceeds the tolerance, the calibration software will post an error. |
Number or Retry Range: 0 — 9 Default: |
If the number of retry is >0, the calibration software will re-run the detect circle instruction if the current circle detection has either a fit error or a radius error. |
Contact Position Register |
If the position register number is any number other than 0, iRCalibration Frame Set will copy the contact position to the position register. |
Table 2. Frame Schedule Detail Schedule Setup
ITEM | DESCRIPTION |
Auto Update Value: TRUE |
This item indicates whether the iRCalibration Frame Set FIND END instruction will update the corresponding $mnuframe or not. If you set Auto Update to TRUE and run the iRCalibration Frame Set teach pendant program, the current $mnuframe will be updated based on the offset. |
Store Offset Value: TRUE or FALSE Default: FALSE |
This item stores the cell calibration offset to a specific position register. |
in PR[0] |
If this is non-zero and "Store Offset" is TRUE, then the UFrame offset is stored in the specified position register. |
Max XYZ Offset: Min: 0.01 mm Max: 100 mm Default: 2.0 mm |
This item indicates the tolerance for any detection point shifting. If the distance between the nominal (reference) detection point and the newly detected point is larger than this value, iRCalibration Frame Set will post a warning message. |
Report on DOUT[0]: |
If this is non-zero and iRCalibration Frame Set detects an error then this output port will be pulsed high for 500 milliseconds. |
Fit Error Register. |
If this item is non-zero then iRCalibration Frame Set will store the mean fit error of the detection points in this register. This value is the average deviation from nominal in the search direction of each detection point after the offset is applied |
Max Orient Change: Min: 0.01 degrees Max: 10 degrees Default: 2.0 degrees |
This item indicates the maximum tolerance for orientation changes. If the orientation of the frame exceeds this tolerance, iRCalibration Frame Set will post a warning message. |
Mean Error Register Range: 0 — 999 Default: 0 |
If the register number is greater than 0, iRCalibration Frame Set writes the mean error to this register. |
Max. Error Register Range: 0 — 999 Default: 0 |
If this item is greater than 0, iRCalibration Frame Set writes the computed maximum error to this register. |
Max Dev Register: |
If this item is non-zero, iRCalibration Frame Set will store the maximum deviation in this register. This is the distance between any of the nominal (reference) detection points and the corresponding newly detected point before the offset is applied. |
CD Pair Number: Range: 0-4 |
This item is only used in conjunction with the
Coordinated Motion option. If this item is non-zero, iRCalibration Frame Set will update the leader
frame associated with the specified CD Pair Number.
Dynamic-UFrame must be enabled and an active follower UFrame must be set. The Dynamic-UFrame feature of Coordinated Motion can be enabled by setting the system variable $CD_PARAM.$DYN_UFRAME=TRUE. The default is FALSE. Once Dynamic-UFrame is enabled, and a CD-Pair leader group and follower group are selected a menu item appears on the Coordinated Motion Setup menu:, "Follower UFrame Number". This value determines the active dynamic UFrame for the CD pair. By default, this dynamic UFrame is relative to the Leader Frame associated with the CD Pair. Refer to the Coordinated Motion Setup and Operations manual for more information. |
Be familiar with the following guidelines as you create the frame search teach pendant program.
The contact surface should be relatively flat.
The search direction must be approximately perpendicular to the contact surface.
The robot will return to the starting point (or as specified by “return distance” in the detection schedule) after each search.
Multiple searches (in different directions) can be done at the same starting point as long as the search direction is approximately perpendicular to the contact surface.
If the contact surface is not approximately perpendicular to a UFRAME or WORLD axis then search frame must be TOOL. You must orient the tool so that one of the TOOL axes is perpendicular to the contact surface.
The first circle defines the origin of the user frame. The second circle defines the X direction of the user frame and the third circle defines the Y axis of the user frame.
The UFRAME cannot be changed in the calibration program.
The order that you teach the points is important. The order defines where the origin point is.
Table 3. Troubleshooting iRCalibration Frame Set
Error | Cause | Remedy |
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Robot does not make contact with the part. |
Search starts too far from part. |
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Search direction is not correct. |
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Excessive vibration when robot is returning from the contact position back to the search start position. |
Motion speed is too high. |
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Frame correction is inconsistent from search to search (menu or automatic). |
Search points too close. |
Make sure that search points with the same search direction are far apart from each other. |
Irregular part or part with changing dimensions. |
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Frame correction is inconsistent from search to search (Menu operation). |
Convergence tolerance is too high |
Lower the convergence tolerance, be sure to allow for part deviation if applicable. |
Frame correction is inconsistent from search to search (automatic program operation) |
Search iteration is not done. |
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Program master had one or more bad searches. |
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TCP has changed since program master was done. |
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Contact surfaces have changed dimensions since program mastering. |
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