1       Overview

Testing of various methods available to use the internal Torque Sensors in the HC series robots for External Force Control so that a continuous Force can be applied to a work piece.

1.1        Scope

Several different methods have been developed to allow an HC series robot to apply a specific Force as sensed by the internal Torque Sensors.  They vary in complexity and utility.  Furthermore, the latest MotoFit method makes a previous method inoperable unless MotoFit is disabled and the previous method re-enabled.  Testing was performed to compare and contrast these methods so that users can select the most suitable approach for a given application.

1.2        Testing Equipment

To perform this testing procedure the following items were used.

• YRC1000micro with YBS4.11.00A(JP/EN)-00 controller software, HC10DTP.
• Standard Pendant for non-MotoFit Method testing.
• Smart Pendant with v3.0.0 and MotoFit Extension v1.0.0 for MotoFit Method testing.
• Schunk 3-jaw pneumatic gripper.
• Digital scale and Pin for Force measurement testing.

2       Testing Setup

2.1        Preparation and General Impressions

Several manuals were referenced during the physical testing including:

• YRC1000/YRC1000micro Collaborative Operation Instruction rev.15 (HW1484764)
• YRC1000/YRC1000micro OPTIONS INSTRUCTIONS for MotoFit (HW1484285)
• YRC1000/YRC1000micro Supplementary Instruction for MotoFit Smart Pendant Extension (HW2481011)

The Standard Pendant was used for the majority of the non-MotoFit method testing as it has full native controller feature support except for MotoFit.  In order to setup MotoFit Force Condition Files with the Standard Pendant the controller must be networked to a PC where the FSE-Tool software is installed.  This FSE-Tool method was not tested.

The Smart Pendant was used for the majority of the MotoFit method testing as it has a MotoFit Extension app written to support it natively.  Unfortunately, some of the implementation was lacking for the non-MotoFit method as the Smart Pendant does not allow editing required GPOUT signals except using the Classic Interface.  The Smart Pendant also does not allow for the MotoFit application to be temporarily disabled as does the Standard Pendant.  It does allow the user to completely remove the application.

2.2        Testing Equipment

2.2.1   Photograph of Test Cell

2.2.2   Settings

It was confirmed that External Force Control can be performed without the robot in PFL mode.  However, all Force testing was performed in PFL mode to ensure that Escape from Clamping would execute if any mistakes were made.  It should be noted that External Force Control disables PFL while in operation but does NOT turn off the Green PFL indicator lamp on the B-axis cover.  It is up to the user to perform a comprehensive Risk Assessment and confirm their application conforms to the applicable safety standards ISO 10218-1and ISO 10218-2.

3       SKILLSND (pre-MotoFit) Method

Prior to the standard installation of MotoFit (YAS 4.13/YBS 2.43 or later) External Force Control could be enabled by using the MotoPlus function SKILLSND.  This allows the automatic use of UNTIL Control on Moves.  The robot will perform programmed Moves UNTIL a specified External Force level is achieved.

3.1        Disabling MotoFit

When MotoFit is enabled it disables the use of the SKILLSND method for External Force Control and so must first be disabled if this method is desired to be programmed.

3.1.1   Standard Pendant

MotoPlus APL. -> MotoPlus MONITOR

Press on Application Run Flow

Highlight the MotoFit_YRC(m).out app, press <-Remove, Set Flow, and then Close.

3.1.2   Smart Pendant

The Smart Pendant requires that the MotoFit App be completely uninstalled.  From the Main Menu select System Settings -> Controller

            And then MOTOPLUS APPLICATIONS

Select the MotoFit_YRC(m) app and then press the trashcan icon to be prompted to DELETE it.  Delete the app and re-boot the controller.

3.2        Enabling GPOUT signals for SKILLSND

When MotoFit is enabled it will disable the use of the SKILLSND method for External Force Control and so this must first be re-enabled if this method is desired to be programmed.

3.2.1   Standard Pendant

IN/OUT -> GENERAL PURPOSE OUTPUT

Select on OUT#0001, key in 4057, and press Enter.

Cursor to the bullet for OUT#4057 and then press INTERLOCK + SELECT.  OUTPUT#4057 and OUTPUT#4058 will turn on.

3.2.2   Smart Pendant

The Smart Pendant does not natively support enabling General Purpose Outputs and so the Classic Interface will need to be used.  From the Main Menu select System Settings -> Classic Interface

Turn the Pendant Mode Selector Key to Remote and press START CLASSIC INTERFACE

Press Connect to connect to the Classic Interface.  Use the Classic Interface Virtual Standard Pendant to enable OUT#4057 and OUT#4058 per section 3.2.1.

3.3        Programming

The Inform Command SKILLSND “STARTUNTIL_F=##_X=##_Y=##_Z=##” is used to initiate External Force Control.  Only one FXYZ Parameter is necessary and multiple can be used.

Example

3.4        Performance

Once External Force Control is enabled using the SKILLSND method the robot will perform any included Moves UNTIL a STARTUNTIL Force Parameter level is achieved.  Once the Force Parameter level is achieved the robot will stop and other actions can be scheduled to occur.

Warning:  If multiple Move commands are included in the SKILLSND loop and the STARTUNTIL Force Parameter level is achieved before the last Move is being executed, the robot will continue on to the next Move command once the STARTUNTIL Force parameter level is no longer exceeded.  This will occur only one time and the robot will not stop again if the STARTUNTIL Force Parameter level is exceeded another time.

The faster the programmed Move speed while performing External Force Control, the higher the Force level the robot will achieve due to the additional path traveled while decelerating.  Therefor it is important to Move at very slow speeds for more precise control of the desired programmed Force.

4       MotoFit Method

MotoFit is usually enabled as standard on all current HC robots (YAS 4.13/YBS 2.43 or later) and eliminates the ability to use the prior SKILLSND method.  It is supported on the Standard Pendant but requires a PC with FSE-Tool software to be networked to the controller in order to program the MotoFit Force Condition Files.  This was not tested.  The Smart Pendant with MotoFit Extension v1.0.0 was utilized as it allows for native programming of the MotoFit Force Condition Files.

4.1        Programming

Utilize the MotoFit Utility to program a Force Condition File, and then add IMPON, FSCH, and IMPOFF commands to the program.  Details on how to do so are shown in the MotoFit for HC Series: Force Following video found here:

https://knowledge.motoman.com/hc/en-us/articles/21481333120663-MotoFit-for-HC-Series

Example

Highlight the FSCH-1 command line and press the gear to view and Detail Edit FSCH-1 Arguments.

FSCH-1 can provide up to two output signals for when an Argument value is exceeded.

4.2        Performance

No native abilities are triggered by the Output signals that are turned on by the MotoFit FSCH Macro.  The Outputs can be used as the logical UNTIL condition for any Move command to mimic the behavior of the previous SKILLSND method of External Force Control.  However, they can also be used to trigger more complex robot activities such as starting an Interrupt Job.

The faster the programmed Move speed while performing External Force Control, the higher the Force level the robot will achieve due to the additional path traveled while decelerating.  Therefor it is important to Move at very slow speeds for more precise control of the desired programmed Force.

5       Conclusions

• The option to use the SKILLSND method or MotoFit method to enable External Force Control on an HC robot depends on the Software Version of the controller. 
• SKILLSND has a default ability to apply a Force.  Additional programming is necessary if other actions are required.  The MotoFit method has no default ability and requires additional programming for actions desired after a Force Detection level is exceeded.
• MotoFit cannot be used if the SKILLSND method is enabled.
• A user can easily switch between the SKILLSND and MotoFit methods on a Standard Pendant.
• A user can switch from the MotoFit method to the SKILLSND method on a Smart Pendant.  Re-enabling MotoFit can be accomplished by reloading the MotoFit_YRC(m).out MotoPlus application.
• Most capabilities afforded by the MotoFit method are not natively supported by the Smart Pendant and require programming through the Classic Interface.
• The faster the programmed Move speed while performing External Force Control, the higher the Force level the robot will achieve due to the additional path traveled while decelerating.  Therefor it is important to Move at very slow speeds for precise control of the desired programmed Force.