Helper Functions and Program Logic

This page serves as a guide to the helper functions used within the programs generated by Verbotics Weld, and the logic which these programs follow.

Program Logic

Verbotics Weld utilises multiple essential helper functions that make up the core logic path of a verbotic’s welding program. This logic path is illustrated below:

../../_images/logic-flow-2.png

Program Logic Flowchart

Note: ACTION represents either a welding or sensing motion. E.g. (VbAfterWeld)

Following the diagram above, the program heavily relies on the 3 essential boolean helper-functions to direct your programs path. These being VbSkipWeld, VbFromHome and VbToHome:

  • VbSkipWeld: Allows the program to determine if the proceeding weld should be skipped or completed.

../../_images/VbSkipWelds.png

Flowchart for the Skip Welds Helper Function

  • VbFromHome: Informs the program whether the tool will be approaching the next action (e.g. sense, weld) from a home position, or from the previous position where it finished its last action.

  • VbToHome: Allows the program determine if the robot can retain its current position, or if it needs to return to its set home position.

Note

A weld should only ever be skipped when the program has commanded the robot back to the home position. Skipping a weld from any other location will result in potential collisions.

In addition to these 3 decision-based helper functions, there are also several helper functions which complete specific processes at different points of the program:

  • VbBeforeRun: Executes any additional code within the function before the start of the program and initialises robot-specific variables.

  • VbAfterRun: Executes any additional code within the function after the end of the program.

  • VbBeforeTouchSense: Executes any additional code within the function before starting a touch sense motion and sets the searchError flag to false.

  • VbAfterTouchSense: Executes any additional code within the function after completing a touch sense motion and handles search errors if found.

  • VbBeforeWeld: Executes any code within the function before the start of a welding motion.

  • VbAfterWeld: Executes any code within the function after the end of a welding motion.

Examples

The following examples present several scenarios that may occur in your programs. The provided pseudocode on the left shows the steps the program follows, while on the right a diagram illustrates the logic path as the program advances.

Manual Weld Skip

A client wants to manually skip welds 1 and 2 in their program. To do this, an array containing these 2 welds is included at the start of the program, and every time skip welds is called, the current weld ID is checked against this array.

This exemplifies how you can include an array consisting of any welds you wish to skip and how the logic of this situation should work.

  1. VbBeforeRun

  2. Array of Welds to be Skipped Initialised

  3. VbSkipWeld = False

  4. VbFromHome = True

  5. Approach From Home

  6. VbBeforeSense

  7. VbAfterSense

  8. VbToHome = True

  9. Return To Home

  10. VbSkipWeld = True

  11. Weld 1 Skipped

  12. Return to Home

  13. VbSkipWeld = True

  14. Sense 2 Skipped

  15. Return to Home

  16. VbSkipWeld = True

  17. Weld 2 Skipped

  18. Return to Home

  19. VbSkipWeld = False

  20. VbFromHome = True

  21. Approach From Home

  22. VbBeforeSense

  23. VbAfterSense

  24. VbToHome = False

  25. VbSkipWeld = False

  26. VbFromHome = False

  27. Approach From Previous

  28. VbBeforeWeld

  29. VbAfterWeld

  30. VbToHome = True

  31. Return To Home

  32. VbAfterRun

  33. END
../../_images/manual-skip.png

Program Logic Example

Perform Weld Range

Skip on Sense Error

For this example, the program detects an error during the sensing stage of weld 2 and as a result returns home before skipping weld 2 and advancing to the sensing of weld 3.

This exemplifies how when an error is detected, the program will record the current WeldID that raised the error in an array. This array is used to determine when the program needs to return home and skip the relevant weld.

  1. VbBeforeRun

  2. VbSkipWeld = False

  3. VbFromHome = True

  4. Approach From Home

  5. VbBeforeSense

  6. VbAfterSense

  7. VbToHome = False

  8. VbSkipWeld = False

  9. VbFromHome = False

  10. Approach From Previous

  11. VbBeforeWeld

  12. VbAfterWeld

  13. VbToHome = False

  14. VbSkipWeld = False

  15. VbFromHome = False

  16. Approach From Previous

  17. VbBeforeSense

  18. VbAfterSense

  19. Weld Added to Errors

  20. VbToHome = True

  21. Return To Home

  22. VbSkipWeld = True

  23. Weld 2 Skipped

  24. VbFromHome = True

  25. Approach From Home

  26. VbBeforeSense

  27. VbAfterSense

  28. VbToHome = False

  29. VbSkipWeld = False

  30. VbFromHome = False

  31. Approach From Previous

  32. VbBeforeSense

  33. VbAfterSense

  34. VbToHome = True

  35. Return To Home

  36. VbAfterRun

  37. END
../../_images/sense-remove-weld.png

Program Logic Example

Complete List of Helper Functions

Below is a list of the helper functions common across all robots. The naming below is based off the ABB robot naming convention, however for the the specific helper function names for your robot, see the relevant system integrator page for your robot.

Helper Function Name

Definition

Use

VbBeforeRun

Executes any additional code within the function before the start of the program and initialises robot-specific variables

Add the code specific to your robot here, and any additional code you wish to execute prior to program start

VbAfterRun

Executes any additional code within the function after the end of the program

Include any additional code you wish to run after the welding program has completed here.

VbBeforeTouchSense

Executes any additional code within the function before starting a touch sense motion and sets the searchError flag to false.

Called prior to starting a touch sense motion, include any code relating to touch sense preparation or specific adjustments here.

VbAfterTouchSense

Executes any additional code within the function after completing a touch sense motion and handles search errors if found.

Called after a touch sense motion has been completed, in addition to the error detection and handling, can also run user-added code prior to error handling.

VbBeforeWeld

Executes any code within the function before the start of a welding motion

Called prior to a welding motion, add any specific welding operation adjustments or code here.

VbAfterWeld

Executes any code within the function after the end of a welding motion

Called after a welding motion, include any post-weld code in this procedure.

VbSkipWeld

Retrieves the weld data of the weld being skipped, if an error is detected for that weld then that weld is skipped. Otherwise, the weld is undertaken. Robot MUST be returned to home position before calling this procedure

Called at the start of every loop to determine if the next weld is to be skipped. Should only ever be called after VbToHome to ensure the robot is returned to its home position before skipping a weld

VbToHome

Returns the robot to the home position if a search error occurs, else the robot remains in its current position.

Called to determine if any errors exist for the current weld, if an error is identified, returns the robot to the home position.

VbCutWire

Executes additional code related to cutting the robot wire, robot MUST be returned to home position before calling this procedure.

Called only after the robot has returned to the home position and executes your robot’s specific wire cutting code that is to be included in this procedure.

WbCleanTorch

Executes additional code related to cleaning the torch, robot MUST be returned to home position before calling this procedure.

Called only after the robot has returned to the home position and executes your robot’s specific torch cleaning code that is to be included in this procedure.

VbModifyToolData

Modifies the tool data using the extra code added to this procedure.

Optional: Include any tool data modifications in this function to return an updated tool with the new data.

VbModifyWObjData

Modifies the wobjdata using the extra code added to this procedure.

Optional: Include any desired adjustments to the work object data in this function to return an updated wobj to the program.

VbSearchL

Conducts the robots search motion using touch sense in order to return an updated offset for increased accuracy.

Called whenever a sensing motion is required, allows program to retrieve an updated offset to be used when welding. Uses touch-sense to complete this.

VbLaserSearchL

Conducts the robots search motion using laser sense in order to return an updated offset for increased accuracy.

Called whenever a sensing motion is required, allows program to retrieve an updated offset to be used when welding. Uses laser-sense to complete this.