ScrewRetighten Object

The ScrewTighten object is a force guide object used to loosen screws once, while moving the robot by pressing in a specified direction with a specified amount of force, then retighten screws.

The diagram above provides a visual representation of a ScrewTighten object. After executing the ScrewTighten object, if the screw is not tightened properly, the robot loosens the screw with pressing force in the screw tightening direction shown by the yellow arrow and retighten.

The ScrewRetighten object can apply end conditions related to the screw tightening completion signal given by driver, and force and position. Each end condition is always applied.

When all the success conditions for each end condition are met: The ScrewRetighten object execution ends. The execution is determined as succeeded and proceed to the next force guide object.

When at least one of the failure conditions for each end condition is met: The ScrewRetighten object execution ends. The execution is determined as failed and abort the force guide sequence.

End condition	Success condition
End conditions related to the screw tightening completion signal	The screw tightening completion signal given by driver is received.
End conditions related to position	The moving distance from the force guide object start point in the axial direction specified in PressOrient is within the range of ApproachDist + ScrewLength - DistCheckTol to ApproachDist + ScrewLength + DistCheckTol

End condition	Failure condition
End conditions related to the screw tightening completion signal	The screw tightening completion signal given by driver is not received.
End conditions related to position	Before receiving the screw tightening completion signal, the following is satisfied: The moving distance from the force guide object start point in the axial direction specified by PressOrient exceeds ApproachDist + InsertDepth + DistCheckTol. Alternatively, after receiving the screw tightening completion signal, the following is satisfied: The moving distance from the force guide object start point in the axial direction specified by PressOrient does not reach ApproachDist + InsertDepth - DistCheckTol.

Property guidelines for the ScrewRetighten object

Step 1. Set basic information
Set properties (Name, Description, StepID, AbortSeqOnFail) related to the basic information.

Properties	Description, setting guide
Name	This property sets names of force guide objects. Set a particular name.
Description	This property sets descriptions about force guide objects. Describe the operations. Set a character string.
Enabled	Set whether to execute the force guide object.
	True : Normal
	False : When you do not execute the force guide object (e.g., when you execute another force guide object instead).
StepID	StepID during the force guide object execution. Set an ID. StepID is an ID which is recorded in the log data. It helps you to understand which log data support a process. It is applied when AutoStepID of the force guide sequence is False.
AbortSeqOnFail	Set whether to abort or continue the force guide sequence when the force guide object fails.
	True : Normal End a force guide sequence.
	False : Cases where the force guide sequence contains recovery operations in case of failure; cases where the sequence will be able to continue even in the event of a failure.

Step 2. Set force control functions
Set properties (AddRetightenPressForce, RetightenPressForce) related to the pressing direction and force control functions.

Properties	Description, setting guide
AddRetightenPressForce	This property sets a pressing force to apply to retighten a screw. It is the force to apply to PressForce of the ScrewTighten object to prevent the screw from coming out of the driver bit during the screw tightening operation. Normally set to 0. If the screw comes out during the screw retightening operation, add the force gradually.
RetightenPressForce	This property displays the pressing force to retighten the screw. It is the value obtained by adding AddRetightenPressForce to PressForce of the screw tightening object. Read only. It cannot be edited.

Step 3. Set driver operation
Set properties (LoosenTime) related to driver operation.

Properties	Description, setting guide
LoosenTime	This property sets a time for loosening screw. If the driver screw loosening completion bit is not set in the robot hand settings, rotate the driver in the loosening direction for the set time. If the screwdriver loosening completion bit is set in the robot hand settings, rotate the driver in the loosening direction until the screw loosening completion signal is received or the set time elapses.

Details on the properties of the ScrewRetighten object

• Name Property
  This property sets a particular name that is assigned to force guide object.
  When creating the screw retighten sequence, name is assigned automatically. Automatically assigned name is added a number after ScrewRetighten (e.g. ScrewRetighten01).
  You can change the name. Set up 16 characters at the maximum. Please use alphanumeric characters and underscores [_]. Note: The initial character cannot be a numeric character.

• Description Property
  This property sets descriptions about force guide objects.
  You can set the character string up to 255 characters.

• StepID Property
  This property sets StepID during the execution of the force guide objects. It is only used when AutoStepID is False.

  	Value
  Minimum Value	0
  Maximum value	32767

  Default: Automatically set according to the numbers of the force guide sequence and the force guide object.

• AbortSeqOnFail Property
  This property sets operations when force guide object fails.
  When True is specified: If the force guide object fails, the program ends the force guide sequence and proceeds to the next SPEL statement.
  When specifying False: If force guide object fails, the program proceeds to the next force guide object without ending the force guide sequence.
  Use this property when you want to continue the force guide sequence (e.g. the recovery processes are included in the force guide sequence when the force guide object fails.)

  Value	Description
  True	Abort the force guide sequence when the force guide object fails.
  False	Start the next force guide sequence when the force guide object fails.

  Default: True

• LoosenTime Property
  This property sets a time for loosening screw.
  If the screw loosening complete bit is configured for the screwdriver in robot hand settings, screw loosening will stop if the screw loosening complete signal is received before the loosen timeout elapses. Screw loosening will stop regardless of whether a screw loosening complete signal is received when the loosen timeout runs out.

  	Value (unit: [sec])
  Minimum Value	0.1
  Maximum value	1

  Default: 0.1

• AddRetightenPressForce Property
  This property sets a pressing force to apply to retighten a screw.
  It is the force to apply to PressForce of the ScrewTighten object to prevent the screw from coming out of the driver bit during the screw tightening operation. Normally set to 0.
  If the screw comes out during the screw retightening operation, add the force gradually.

  • If PressOrient of the ScrewTighten object is +Fx, +Fy, and +Fz:

    	Value (unit: [N])
    Minimum Value	-10
    Maximum value	0

    Default: 0

  • If PressOrient of the ScrewTighten object is -Fx, -Fy, and -Fz:

    	Value (unit: [N])
    Minimum Value	0
    Maximum value	10

    Default: 0

• RetightenPressForce Property
  This property displays the pressing force to retighten the screw.
  It is the value obtained by adding AddRetightenPressForce to PressForce of the screw tightening object. Read only. It cannot be edited.

Details on the results of the ScrewRetighten object

• EndStatus Result
  It is a result of the execution.
  It will be succeeded when satisfying "success conditions" described in
  ScrewRetighten Object .

  Value	Description
  Passed	Force guide object is succeeded.
  Failed	Force guide object is failed.
  NoExec	Force guide object is not executed.
  Aborted	Aborted during the execution of force guide object.

• Time Result
  This is the time required for execution.
  Unit: [sec]

• EndForces Result
  It is force and torque when force guide object ends. Acquire values of Fx, Fy, Fz, Tx, Ty, and Tz.
  Unit: Fx, Fy, Fz [N] / Tx, Ty, Tz [N・mm]
  EndPos Result
  Positions when the force guide object ends. Acquire values of X, Y, Z, U, V, and W.
  Unit: X, Y, Z [mm] / U, V, W [deg]

• AvgForces Result
  Average values of force and torque during the force guide object execution. Acquire values of Fx, Fy, Fz, Tx, Ty, and Tz.
  Unit: Fx, Fy, Fz [N] / Tx, Ty, Tz [N・mm]

• PeakForces Result
  Peak values of force and torque during the force guide object execution. The peak value is a value which absolute value is the largest. Acquire values of Fx, Fy, Fz, Tx, Ty, and Tz.
  Unit: Fx, Fy, Fz [N] / Tx, Ty, Tz [N・mm]

• PosCondOK Result
  Shows whether the end conditions related to position were satisfied.

  Value	Description
  True	Satisfy the end conditions related to position.
  False	The end conditions related to position are not satisfied.

• IOCondOK Result
  Shows whether the end conditions related to I/O were satisfied.

  Value	Description
  True	Satisfy the end conditions related to I/O.
  False	The end conditions related to I/O are not satisfied.