Confirmation of Tool and Hand Setting

The following describes tool setting procedures.
In the ScrewTighten sequence, you need to consider the behavior of the actual screw tightening direction and the current tool settings.

1. Use a caliper to measure the distance of X, Y, and Z from the J6 flange plane to the end of the electric screwdriver.

2. Execute the following in [Command Window].
   Enter the values measured in procedure (1) in "LengthX, LengthY, LengthZ".

   > Tlset 1,XY(LengthX,LengthY,LengthZ,0,0,0)
   

3. Click Epson RC+ menu-[Tools]-[Simulator].
   The [Simulator] window is displayed.

4. Select the object tree-[Manipulator Name]-[Tool].

5. Place a checkmark in "No.1"-[Visible] check box.

6. To confirm that the tool setting is correct, compare the display of the [Simulator] window and the orientation of the actual robot.
   
   According to the display of the [Simulator] window, you will see that screw driving is performed to +Z direction of the tool.
   

The following describes Hand setting procedures.
Allocate the forward and reverse rotation of the electric screwdriver to the output bit of the controller I/O, and allocate the screw tightening completion signal to the input bit of the controller I/O.

1. Click Epson RC+ menu-[Tools]-[Robot Manager]. The [Robot Manager] dialog box appears.
2. Select the [Hands] panel and open the panel.
   
3. Select "Hand 1" and click the [Configure...] button.
   The configuration screen for Hand 1 is opened.
4. Place a checkmark in the [Defined] check box, and change the following items.

   Item		Value	Description
   Label		driver1	Enter a label name.
   Series		Screwdrivers	Select "Screwdrivers" in [Series].
   Hand_On	Start_Controller I/O Bit	Driver forward rotation bit	Set the output bit allocated to the driver forward rotation.
   	Start_I/O State	On	This is the state of the driver forward rotation bit when the driver rotates forward.
   	Complete_Controller I/O Bit	Completion of screw driving bit	Set the input bit allocated to the screw tightening completion signal.
   	Complete_I/O State	On	This is the state of the screw tightening completion bit when the driver performs torque-up.
   Hand_Off	Start_Controller I/O Bit	Driver reverse rotation bit	Set the output bit allocated to the driver reverse rotation.
   	Start_I/O State	On	This is the state of the driver reverse rotation bit when the driver rotates in the reverse direction.

   
5. Click the [Apply] button to save the settings, and click the [Close] button to close the configuration screen for Hand 1.

Position Teaching

The following describes how to teach a sequence start position of ScrewTighten sequence.

1. Click Epson RC+ menu-[Tools]-[Robot Manager].
   The [Robot Manager] dialog box appears.
2. Select [Jog & Teach] and open the panel.
3. Select "1" on [Tool].
   
4. An electric screwdriver attaches to a screw.
5. Use the Jog button to move the robot to the following positions.
   • X and Y directions : The end of the screw is within the taper part of the screw hole
   • Z direction : The end of the screw is 1mm above the screw hole
     
6. Select Epson RC+ menu-[Tools]-[Force Monitor]. The [Force Monitor] dialog box is displayed.
   
7. Select [Short] button on [Jog Distance].
   Click the Jog button several times to move the robot to -Z direction until the end of screw contacts with screw hole.
   When the robot contacts with the object, output value of Force Sensor changes. Check the changes of monitor value by the timing of the jog motion.
   
8. Select the [Medium] button on [Jog Distance].
   So that the screw will be in a non-contact state, click the Jog button two times to move the robot 2mm in the +Z direction.
   
   This is a start position of sequence and a position where the Force Sensor is reset.
9. Select "P1" in the [Point] dropdown.
10. Enter "ScrewStart" in [Point Label]. Click the [OK] button.
    Click Epson RC+ menu-[File]-[Save All]. The file is saved.

Sequence wizard

The following describes how to create a dedicated force guide sequence for screw driving.

1. Enter "ScrewSeq" in the [Enter name for new sequence] box. Click the [Next] button.
   

2. The [Step 2: Select sequence type] dialog box is displayed.
   Select [System].
   Click the [Next] button.
   

3. The [Step 3: Select system sequence] dialog box is displayed.
   Select [Tighten screw].
   Click the [Next] button.
   

4. The [Step 4: Set screw parameters] dialog box is displayed. Change the properties according to the table below. Click the [Next] button.
   

   Item	Value	Description
   Robot Hand	1	Specify the number set for the hand used in this sequence. The hand label will appear after the hand number.
   Driver rotation speed	247	Set the rotation speed of electric screwdriver. Set this to the rotation speed of your electric screwdriver.
   Screw length	5	Set the length of the screw. Set this to the length of the screw in use.
   Screw lead length	0.4	Set the screw lead length. Set this to the lead length of the screw in use.

5. The [Step 5: Select the robot tool to use for the end effector] dialog box is displayed. Change the properties according to the table below. Click the [Next] button.
   

   Item	Value	Description
   Tool	1	Specify the number set for the tool used in this sequence.

6. The [Step 6: Set tool offsets] dialog box is displayed.
   Set tool offset values. These values can be left as the default values and do not need to be changed.
   Click the [Next] button.
   

7. The [Step 7: Set the screw tighten operation coordinate system and direction] dialog box is displayed.
   As the screw tightening direction is in the +Fz direction in the tool coordinate system, these values can be left as the default values and do not need to be changed.
   Click the [Next] button.
   

8. The [Step 8: Select whether to enable screw retightening] dialog box is displayed.
   Set whether to enable screw retightening. As screw retightening is not performed, this value can be left as the default value and does not need to be changed. Click the [Next] button.
   

9. The [Step 9: Set the approach distance for the screw driving operation] dialog box is displayed.
   Change the properties according to the table below.
   Click the [Next] button.
   

   Item	Value	Description
   Approach distance	2	Set the distance from the end of the screw to the hole face. Set this to 2 mm.

10. The [Step 10: Set the screw driving force required] dialog box is displayed.
    Select [Select force based on screw size].
    Change the properties according to the table below.
    Click the [Next] button.

    Item	Value	Description
    Screw size	Medium (M3)	Set the force applied based on the screw size. When set to Medium (M3), the force applied is Set to -4N.

11. The [Step 11: Set the end condition for screw tightening force] dialog box is displayed.
    Change the properties according to the table below.
    Click the [Next] button.
    

    Item	Value	Description
    Screw collision detection force	-20	Set the force identified as a collision when the screw comes into contact with an area outside the hole. . Set this to a sufficiently greater value than the screw pressing force. Set this to -20N. Set this to a tolerable value considering the workpiece in use.

12. The [Finish] dialog box is displayed.
    Click the [Finish] button.
    

13. Check that the [ScrewSeq] sequence has been created.
    

Setting Confirmation

The following describes how to check whether the settings for screw tightening direction are correct by using a simulator.

1. Click Epson RC+ menu-[Tools]-[Simulator].
   The [Simulator] window is displayed.
2. Click the object tree-[Tool].
   Place a checkmark in the "No.1"-[Visible] check box. An arrow for "Tool 1" is displayed.
3. Click the object tree-[Force]-[Force Guide]-[ScrewSeq].
   Place a checkmark in the "ScrewTighten01"-[Visible] check box.
   
4. Confirm that the yellow arrow direction is the same as the screw tightening direction.

Motion by Force Guidance Function

The following describes how to run the created ScrewTighten sequence by Epson RC+.

1. Open the [Force Guide] window.
2. Select the [Jog] tab.
3. Click the [POWER HIGH] button.
   If the robot might break the workpiece, operate in "Low Power Mode".
4. Click the [Execute] button.
   Program is compiled and transmitted to the Robot Controller.
   If the setting is not correct, an error occurs. Check the settings so far and follow the error message to modify the parameters.
5. When the operation is performed properly, is displayed on the upper left of the flowchart and the screw tightening is completed.
   
   

Return to the Non-Contact State

After completing ScrewTighten sequence, force continues to be applied to between the robot and the workpiece. To prevent the robot and the end effector from malfunction or damages, after the operation ends, make sure that no force is applied to the object. If it is obvious that no force is applied to the object, you can omit this step.

Steps to return to a non-contact state are as follows:

• Click Epson RC+ menu-[Tools]-[Robot Manager]-[Jog & Teach] panel-[Jog] group and perform jog motion manually to move the robot away from the object.
• Click Epson RC+ menu-[Tools]-[Robot Manager]-[Jog & Teach] panel-[Execute Motion] tab and move the robot away from the object.
• Execute Move command on [Command Window] and move the robot away from the object.
• Add SPELFunc object after ScrewTighten object, and automatically move the robot away from the object at the end of the force guide sequence.

The following describes how to return to non-contact state by clicking [Robot Manager]-[Jog & Teach]-[Execute Motion] tab.

1. Display the [Robot Manager] dialog box.
2. Click the [Jog & Teach] tab.
3. Select the [Execute Motion] tab.
4. Select "Move" in [Command].
5. Select "P1" in [Destination].
6. Click the [Execute] button.
   The robot moves to the start point: P1. Now, it is the non-contact state.
   

Motion Analysis by Monitor

The following describes how to use Epson RC+ to check the operation results of a force guide sequence.

1. Open the [Force Guide] window.
2. Click the sequence flow of [ScrewSeq].
3. Select the [Monitor] tab. Select the [Force] tab.
   Force and position during the [ScrewSeq] sequence execution are displayed in the graph.
   
4. Select the [1D Pos] tab.
   Graph for analysis is displayed. (horizontal axis: Time, vertical axis: Position)
   As you can see by looking the Position Z graph, CurZ (current position) is lowered by about 7 mm. It indicates that the robot moves in the screw tightening direction by 2mm of the approach distance and by 5mm of the screw length.
   
5. Select the [2D Pos] tab.
   Graph for analysis is displayed. (horizontal axis, vertical axis: Position)
   You can see what you have checked on the [1D Pos] tab as a graph projected on each plane.
   Be careful of the scale difference of horizontal axis and vertical axis when checking the graphs.
   
6. Select the [Pos Diff] tab.
   Record shifts by force control as relative position changes.
   It is different from the graph on the [1D Pos] tab.
   
7. Change the unit of the graph and check the changes of force or positions.

If it is not tightened correctly, the setting may not be correct. Refer to the following and check the procedures of the tutorial.

• Whether a pressing force direction is correct
• Whether the start point is largely moved from a hole
• Whether the setting of the approach distance is correct
• Whether the setting of the driver rotation speed, screw length, and lead length are correct

Advanced Tasks

Let's do the following advanced tasks.
The default end condition for the screw tighten sequence position is whether the position of the object from the start of the screw tighten sequence is within the "approach distance + screw length ± 1 mm".
Under this condition, the system may erroneously detect that the screw tightening process has ended successfully even if the screw gets caught and is improperly tightened.
To counter this, set stricter finishing position conditions, and add a sequence to loosen and retighten the screw if the completion conditions are not met.

1. Change the [ScrewTighten01] property as follows.

   Item	Value	Description
   DistCheckTol	0.1	Specify the success condition range for distance moved from the motion start point. Set the success condition range to the "approach distance + screw length ± 0.1 mm".

2. In the flowchart, right click [Sequence ScrewTighten], and then click [Sequence Wizard].
   The screw tighten sequence wizard will be displayed.
   

3. Without changing any settings, click the [Next] button until the [Step 8: Select whether to enable screw retightening] dialog box is displayed. Select the [Enable retighten] checkbox.
   

4. Click the [Next] button until the [Step 9: Configure screw retightening operation] dialog box is displayed.
   Change the properties according to the table below.
   Click the [Next] button.
   

   Item	Value	Description
   Loosen timeout	0.5	Set the screw loosening duration. Set this to 0.5 seconds.
   Additional force	0	Set the additional screw pressing force when retightening. Set this to 0 N.

5. The [Step 10: Change Summary] dialog box is displayed.
   Click the [Finish] button.
   

6. Check that the [ScrewRetighten01] object has been added.
   

7. Now try running the sequence you have created.

This ends the screw tighten sequence tutorial.