Weight, Inertia, and Eccentricity / Offset Measurement Utility
Functional overview
Epson RC+ 8.0 supports "Weight, Inertia, and Eccentricity/Offset Measurement Utility". It is a function measures and sets the following three parameters with the customer's end effector attached to the robot.
- Load weight: Specify with the weight command
- Weight inertia: Specify with the inertia command
- Eccentricity (offset of weight center of gravity from J6 flange surface for the 6-axis robot)
Measurement methods and compatible models
Two methods to measure:
Static (measured at low speed)
Measures and calculates the parameter value as accurately as possible.
Iteration (measured at high speed)
Sets the target parameter value to use the motor torque appropriately, not to measure the exact value. In particular, for large weight, large inertia, and eccentric end effectors, places importance on setting appropriate values that do not break the robot and are well balanced with speed.
The combination of Static and iteration measurements is determined by the robot model. Table 1 and 2 describe it.
Table 1: Measurement methods and compatible models for the 6-axis robot (Static & iteration)
| Measurement posture (angle for each axis), motion area (motion range angle for each axis) | ||||||||
|---|---|---|---|---|---|---|---|---|
| Measurement parameters | Measurement methods | Measurement speed | J1 | J2 | J3 | J4 | J5 | J6 |
| WEIGHT/OFFSET | Static | Low speed | 0 deg | 0 deg | -3 to 3 deg | 0 deg | -3 to 3 deg | 0 deg |
| INERTIA | Iteration | High speed | 0 deg | 0 deg | 0 deg | 0 deg | 0 deg | 270 to -360 deg |
| version 1.3 compatible models *1 | |||
|---|---|---|---|
| Measurement parameters | Measurement methods | Measurement speed | C4, C8, C12, C4-B, C8-B, C12-B, VT6 *2, *3 |
| WEIGHT/OFFSET | Static | Low speed | ✓ |
| INERTIA | Iteration | High speed | ✓ |
| A combination of measurements | Staic & iteration | ||
*1: Refer to readme in the following project folder for the supported models in the latest version.
C:\EpsonRC80\projects\Utilities\WeightInertiaMeasurement
*2: N2 and N6 are not compatible.
*3: The wall mounting type is not compatible.
Table 2: Measurement methods and compatible models for the SCARA robot (Static & iteration, or iteration only)
| Measurement posture (angle for each axis), motion area (motion range angle for each axis) | ||||||
|---|---|---|---|---|---|---|
| Measurement parameters | Measurement methods | Measurement speed | J1 | J2 | J3 | J4 |
| WEIGHT | Static | Low speed | 0 deg | 0 deg | 0 to -50mm | 0 deg |
| WEIGHT | Iteration | High speed | 0 deg | 0 to 90 deg | 0 mm | 0, 180 deg |
| INERTIA | Iteration | High speed | 0 deg | 0 deg | 0 mm | -180 to 180 deg |
| Eccentricity | Iteration | High speed | 0 to 90 deg | -75 to 90 deg | 0 mm | -360 to 360 deg |
| Eccentricity (for RS3 and RS4) | Iteration | High speed | 0 to 90 deg | 55 to 220 deg | 0 mm | -360 to 360 deg |
| version 1.3 compatible models *1 | |||||
|---|---|---|---|---|---|
| Measurement parameters | Measurement methods | Measurement speed | GX4, GX8, GX4-B, GX8-B, GX4-C, GX8-C, GX10-B, GX20-B, GX10-C, GX20-C, LS3-B, LS6-B, LS10-B, LS20-B*2 | RS3, RS4 | G3, G6, G10, G20 *3, T3, T6, T3-B, T6-B, LS3, LS6, LS20, LS3-B*V1, LS6-B*V1 |
| WEIGHT | Static | Low speed | ✓ | - | - |
| WEIGHT | Iteration | High speed | - | ✓ | ✓ |
| INERTIA | Iteration | High speed | ✓ | ✓ | ✓ |
| Eccentricity | Iteration | High speed | ✓ | - | ✓ |
| Eccentricity (for RS3 and RS4) | Iteration | High speed | - | ✓ | - |
| A combination of measurements | Staic & iteration | Iteration only | |||
*1: Refer to readme in the following project folder for the compatible models in the latest version.
C:\EpsonRC80\projects\Utilities\WeightInertiaMeasurement
*2: Excludes LS3-B*V1, LS6-B*V1.
*3: G1 is not compatible.
Preparation for measurement
When measuring, secure the necessary space for the operation and attach an end effector to the robot to measure. The motion range depends on the model and the corresponding measurement method. Refer to table 1 and 2. This measurement utility also operates in the simulator. Check the motion range on the simulator beforehand. You can also check the approximate measurement time on the simulator. For high-speed measurements, operates with speed 100, accel 100, 100. It cannot be measured with an end effector which strength cannot withstand high speed. In addition, to move a wide motion range, measure without connecting wiring or piping.
Measurement and measurement time
Run a program written in the SPEL+ language to measure.
- Destination to save:
C:\EpsonRC80\projects\Utilities(for default installation) - Project name: WeightInertiaMeasurement
Execute the main function first.
- For the 6-axis robot: Measures in order of weight, offset, and inertia.
- For the SCARA robot: Measures in order of weight, inertia, and offset.
The measurement time takes 4 to 13 minutes. A high-payload (20kg) SCARA robot takes the longest time.
Check for the start of the measurement and the operation at low speed
Before starting the measurement, the following message appears:
Start Measurement: [y: yes, n: no]:
?
To measure, enter "y" or "Y". If you enter any other characters, the measurement exits.
When you enter "y" or "Y", after checking the motion range of all measurements at low speed, measures. Make sure that there are no problems with the motion range. The measurement time takes 2 to 4 minutes.
Display of the setting parameters before starting the measurement
The three setting parameters before starting the measurement appear as follows. It changes when you start the measurement. To return the parameters after measuring, modify them manually.
An example for the SCARA robot:
Current Weight: 1 kg, Current Inertia: 0.016 kgm2, Current Eccentricity: 0 mm.
An example for the 6-axis robot:
Current Weight: 1 kg, Current Inertia: 0.03 kgm2, Current Offset: 0 mm.
Parameter settings by the measurement
After the measurement starts, the above three parameters are changed, and the parameter is confirmed in the order of measurements and set to the Controller. All three parameters are set and the measurement ends. If the measurement is quit in the middle, the setting of the parameter values is not ensured. It is not possible to resume the measurement from the middle. If you quit, start the measurement again from the beginning.
Measurement details and what appears in the Run window
An example of the measurement is shown below. "<<" is a supplementary explanation.
An example of the 6-axis robot measurement (C8, combination of measurement: Static & Iteration)
Weight,Inertia,Offset/Eccentricity Measurement Utility ver. 1.0.0. << version display
2022/9/7 10:39:52
Model: C8-A701S, PerformMode 0
Max Weight: 8 kg, Max Inertia: 0.15 kgm2, Max Offset: 300 mm.
Current Weight: 1 kg, Current Inertia: 0.03 kgm2, Current Offset: 0 mm. <<current set value
ROBOT MOVEMENT AREA
WEIGHT,OFFSET Measurement Movement Area: J1, J2, J4, J6 [0 deg.]; J3, J5 [-3 to 3 deg.]
INERTIA Measurement Movement Area: J1, J2, J3, J4, J5 [0 deg.]; J6 [270 to -360 deg.]
Start Measurement: [y: yes, n: no]:
?y << check for the start of the measurement
WEIGHT,OFFSET Measurement Movement Area: J1, J2, J4, J6 [0 deg.]; J3, J5 [-3 to 3 deg.]
Area Movement Check [Low Power Mode] << low-speed operation for the weight and the offset measurement motion range
INERTIA Measurement Movement Area: J1, J2, J3, J4, J5 [0 deg.]; J6 [270 to -360 deg.]
Area Movement Check [Low Power Mode] << low-speed operation for the inertia measurement motion range
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Start of WEIGHT,OFFSET Measurement for 6axis [Static Method]
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Warm up Movement: J3, J5 (Repeats 10 times)[High Power Mode] << warm-up operation
Start Measurement J3, J5 (Repeats 6 times)
Measurement 1. << starts measurements for the weight and offset (six measurements)
Measurement 2.
Measurement 3.
Measurement 4.
Measurement 5.
Measurement 6.
---------------------------------------
WEIGHT 5.7 kg, OFFSET 35 mm << the measurements and set values for the weight and the offset
---------------------------------------
WEIGHT,OFFSET Measurement and Settings Completed.
------------------------------------------------------------
Start of INERTIA Measurement for 6axis [Iteration Method]
------------------------------------------------------------
Current weight : 5.7 kg, Current offset : 35 mm
Warm up Movement: J6 (Repeats 5 times)[High Power Mode] << warm-up operation
Start INERTIA Measurement: J6
Measurement 1. << starts the measurement for the inertia (one to twelve measurements)
Measurement 2.
Measurement 3.
-----------------------
INERTIA : 0.13 kg*m2 << measured value for the inertia
-----------------------
INERTIA Measurement and Settings Completed.
-----------------------------------------------------------
WEIGHT : 5.7 kg, INERTIA : 0.13 kg*m2, OFFSET : 35 mm << final result and the set value
-----------------------------------------------------------
motor off
2022/9/7 10:43:19
------------- COMPLETE -----------------
An example of the SCARA robot measurement (GX8, combination of measurement: Static & Iteration)
Weight,Inertia,Offset/Eccentricity Measurement Program ver. 1.0.0. << version display
2022/9/7 10:52:40
Model: GX8-A553S, PerformMode 0
Max Weight: 8 kg, Max Inertia: 0.16 kgm2, Max Eccentricity: 150 mm.
Current Weight: 4 kg, Current Inertia: 0.01 kgm2, Current Eccentricity: 0 mm. <<current set value
ROBOT MOVEMENT AREA
WEIGHT Measurement Movement Area: J1, J2 [0 deg.]; J3 [0 to -50 mm.]; J4 [0 deg.]
INERTIA Measurement Movement Area: J1 [0 deg]; J2 [90 deg]; J3 [0mm]; J4 [-180 to 180 deg.]
ECCENTRICITY Measurement Movement Area: J1 [0 to 90 deg]; J2 [-75 to 90 deg.]; J3 [0mm]; J4 [-360 to 360 deg.]
Start Measurement: [y: yes, n: no]:
?y
WEIGHT Measurement Movement Area: J1, J2 [0 deg.]; J3 [0 to -50 mm.]; J4 [0 deg.]
Area Movement Check [Low Power Mode] << low-speed operation for the weight measurement motion range
INERTIA Measurement Movement Area: J1 [0 deg]; J2 [90 deg]; J3 [0mm]; J4 [-180 to 180 deg.]
Area Movement Check [Low Power Mode] << low-speed operation for the inertia measurement motion range
ECCENTRICITY Measurement Movement Area: J1 [0 to 90 deg]; J2 [-75 to 90 deg.]; J3 [0mm]; J4 [-360 to 360 deg.]
Area Movement Check [Low Power Mode] << moves the eccentricity measurement motion range at low speed
--------------------------------------------------------
Start of WEIGHT Measurement for SCARA [Static Method]
--------------------------------------------------------
Warm up Movement: (Repeats 10 times)[High Power Mode] << warm-up operation at high speed
Start WEIGHT: J3 (Repeats 5 times)
Measurement 1. << starts the measurement for WEIGHT (five measurements)
Measurement 2.
Measurement 3.
Measurement 4.
Measurement 5.
-----------------------
WEIGHT : 5.1 kg << measured value for the weight
-----------------------
WEIGHT Measurement and Settings Completed.
------------------------------------------------------------
Start of INERTIA Measurement for SCARA [Iteration method]
------------------------------------------------------------
Current Weight: 4.2 kg
Warm up Movement: (Repeats 5 times)[High Power Mode] << warm-up operation
Start Inertia Measurement: J4
Measurement 1. << starts the measurement for the inertia (one to twelve measurements)
Measurement 2.
Measurement 3.
Measurement 4.
Measurement 5.
Measurement 6.
-----------------------
INERTIA : 0.07 kg*m2 << measured value for the inertia
-----------------------
INERTIA Measurement and Settings Completed.
------------------------------------------------------------
Start of ECCENTRICITY Measurement for SCARA [Iteration Method]
------------------------------------------------------------
Current weight : 5.1 kg, Current inertia : 0.07kgm2
Warm up Movement: (4 movements x 1 set)[High Power Mode] << warm-up operation at high speed
Start ECCENTRICITY Measurement: J1-J4
Measurement 1. << starts the measurement for the eccentricity (one to thirteen measurements)
Measurement 2.
Measurement 3.
Measurement 4.
Measurement 5.
-----------------------
ECCENTRICITY : 90 mm << ends the measurement and sets the value
-----------------------
ECCENTRICITY Measurement and Settings Completed.
------------------------------------------------------------
WEIGHT : 5.1 kg, INERTIA : 0.07 kg*m2, ECCENTRICITY : 90 mm
------------------------------------------------------------
motor off
2022/9/7 10:57:54
------------- COMPLETE -----------------
An Iteration method example of the measurement for the SCARA robot WEIGHT (LS6-B, combination of measurement: Static & Iteration Iteration only)
The measurement for Inertia and eccentricity is omitted because it is the same operation as the GX8 example above.
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Start of WEIGHT Measurement for SCARA [Iteration Method]
-----------------------------------------------------------
Warm up Movement: (Repeats 6 times)[High Power Mode] << warm-up operation at high speed
Start WEIGHT Measurement: J2
Measurement 1. << starts the measurement for WEIGHT (one to thirteen measurements)
Measurement 2.
Measurement 3.
Measurement 4.
Measurement 5.
Measurement 6.
-----------------------
WEIGHT : 1 kg << ends the measurement and sets the value
-----------------------
WEIGHT Measurement and Settings Completed.
Precautions
For the 6-axis robot, this function measures the tip weight of Arm 6. For the SCARA robot, it measures the weight attached to the shaft. For the weight of a workpiece, measure by attaching an equivalent object or set by adding the weight separately. The weight attached to the 6-axis arm 3 or 5 and the SCARA arm 2 should be converted to equivalent weight and added separately.
The weight set value and the inertia set value have the minimum value (about 10% to 20% of the maximum value). 0kg, 0kgm 2, Values close to these are not set. Light end effectors less the minimum value are rounded up to the minimum value. When operating with the simulator, the minimum value is set.
It is recommended to use CollisionDetect with the default "ON". You can use the CollisionDetect command to check the current setting.
> CollisionDetect ON,ON,ON,ON (always OFF in the simulator)The settings for this measurement are as follows: performmode: 0 (normal) accel: 100
Use this setting with the upper limit of performmode "Normal" and accel "100". If you use performmode other than "Normal", change the mode of this measurement as well. When changing, modify the following Gperformmode variables manually and rebuild it before executing it."Function main GPerformMode = 0 '0:normal, 1:boost, 2:low vibration main2 Fend"If you use other than "0" with a robot not compatible with the perform mode, the following message will appear, and exits.
PerfomMode 1 is not supported in this robot. -- end --"This measurement result can be used to set the same model uses the same end effector. It cannot be used for setting to different models (even if the arm length is different). Repeat the measurement with the compatible model.
If an error occurs in the middle of the program, force-quit the program, eliminate the cause (overload of the end effector, collision of the robot, etc.), and run it again.
The following warning message may be output at each measurement and after all measurements.
"Warning: XXXXX over specification, please check the endeffector."(XXXXX is Weight, Inertia, Offset, and Eccentricity)The measured value is too large for the parameter. This measurement program ends after setting the maximum value, but check the design to make sure that there is no problem with the end effector specification.
For not compatible model, the following message appears and the measurement is quit.
N2-A450SR is not supported. -- end --"For the 6-axis wall mounting type, the following message appears and exits.
Wall mounted type manipulators are not supported. C8-A701SW is not supported. -- end --"