Automatic process path optimization

What is automatic process path optimization

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Methodology


The function uses a methodology of iterative steps to find the optimal result. These iterative steps are applied to a set of variables, i.e. orientation angles of the toolpath elements that can be modified during the optimization.


In each iteration step, a range with a number of variations is being built to find the optimum result (= minimal costs) within that range. From that optimum, a new range is being defined from the variation before to the variation after that found optimum. That range again is divided in smaller steps to search for the optimum again.

This process repeats itself until the variation step equals (or is smaller than) the discretization step of the variable or when any other boundary condition has been met.


This process is executed for each of the variables. But each of these variables might give a different optimal orientation of the toolpath position. Therefore, the resulting optimized toolpath position will be a compromise between the results of the individual variables.


In the end, the automated path optimization (APO) evaluates the whole toolpath; i.e. the range (program, group or operation) that has been selected and tries to find an optimized solution that matches with the given quality criteria and then results in minimum costs.


OLP_APO_31



Variation space


OLP_TP_Evaluation_21_242


Information_24

By default not all attributes are being displayed. It is limited to the most common applied. Switching the Expert mode button at the top right of the dashboard will expand the container to show all available attributes.

 

COM_Expert_active



The Variation space defines what modifications can be made to the toolpath elements to search for the optimal solution. It shows all variables that can be included in the optimization process, their range within they can be varied and the distribution step or discretization within that range.


For most technologies or scenarios the default variation space values should do the job; nothing to change here when you are not that familiar with the meaning of these variables.


The variables here might be specific for a technology or a certain technology setup in combination with an OEM brand controller and robot or machine. In other words; the exact content of the container might look different for each case.


The variables are:



Parameter

Description

Optimization options

Remark

COM_RotationTangent

Tangent rotation

 

Varies the toolpath position while rotating it around its tangent direction.

PageParagraph_8 Step size

Rotation value in each iteration step.

Switch to include it in the optimization process.

COM_RotationBiTangent

Bi-tangent rotation

Varies the toolpath position while rotating it around its bi-tangent direction.

PageParagraph_8 Step size

Rotation value in each iteration step.

Switch to include it in the optimization process.

OLP_ToolSingularity

Singularity orientation

Evaluates singularity situations of the robot or machine.

 

In case of a robot scenario, the singularity orientation means the rotation of the toolpath position around its normal axis.

PageParagraph_8 Step size

Rotation value in each iteration step.

 

PageParagraph_8 Deviation cone

Axis with values within the specified cone angle are being optimized.

Switch to include it in the optimization process.

COM_RotationNormal

Normal rotation

(arc welding technology)

Varies the toolpath position while rotating it around its normal direction.

PageParagraph_8 Step size

Rotation value in each iteration step.

Switch to include it in the optimization process.


The Boundary conditions section includes additional parameters that can be introduced to limit the amount of variations. Where normally the tangent and bi-tangent rotation of the toolpath position can vary between -180 and +180 degrees, cause these parameters extra conditions to allow the tangent and bi-tangent axis to rotate only within the range and as long as the boundary condition is still met.



Parameter

Description

Optimization options

Remark

OLP_AngleDev_Process

Max. process angle deviation

 

The maximum allowed process angle deviation from the reference direction.

 

 


An optimization result is accepted when the process angle is smaller or equal to this value.

 

This value can be only edited when its corresponding criteria Process angle deviation has been disabled from the quality evaluation.

OLP_AngleDev_Work

 

OLP_AngleDev_Arcweld_Work

Max. work angle deviation

 

 

 

(arc welding technology)

The maximum allowed work angle deviation from the reference direction.


Only available when the process angle deviation criteria has been replaced by separated work and tool angle criteria.

OLP_AngleDev_Travel

 

OLP_AngleDev_Arcweld_Travel

Max. travel angle deviation

 

 

 

(arc welding technology)

The maximum allowed travel angle deviation from the reference direction.


Only available when the process angle deviation criteria has been replaced by separated work and tool angle criteria.

OLP_AngleDev_Tool

 

OLP_AngleDev_Arcweld_Tool

Max. tool angle deviation

 

 

 

(arc welding technology)

The maximum allowed tool angle deviation from the reference direction.





Optimization control


OLP_TP_Evaluation_22_242


Information_24

By default not all attributes are being displayed. It is limited to the most common applied. Switching the Expert mode button at the top right of the dashboard will expand the container to show all available attributes.

 

COM_Expert_active



The Optimization control is a set of attributes to manage the optimization process.


Attribute

Description

Remark

OLP_TP_Evaluation_26

Heuristic parameter to balance between best result and fastest computation time.

The value can be interpreted as cost tolerance per meter toolpath.

A value of 0 would result in the global best result, i.e. lowest costs, regardless the required computation time.

A value of 1 would mean that even a toolpath having higher costs up to 1 per meter in average would be acceptable as optimization result, though there would be better results with lower total costs.

 

Simply said.

Move the slider to the left to get the best results, with longer calculation times.

Move to the right to get less optimal paths, but in less time.


In the standard optimization process, each toolpath position is analyzed against the collision tolerance that has been set in the simulation settings.

Collision_Override

Override collision tolerance

Option to override the simulation collision tolerance.

With this switch, the tolerance from the simulation settings will be ignored and replaced by the new defined collision tolerance here.

Collision_Tolerance

Collision tolerance

The collision tolerance while running the optimization.

The tolerance between two groups for a collision to be detected. The value is the checking distance between the groups.

 

A value = 0 corresponds to a contact.


COM_IterationSteps

Max. # variations

Divides the range in a maximum number of variations, i.e. step size.


COM_IterationMaxRotation

Max. rotary step

The maximum allowed rotation step per variation of the robot / machine axis.


Cancel

Abort if no solution

Terminates the optimization.

To prevent unnecessary long computation times, the optimization process will be aborted when on the first iteration step no solution has been found.


If the resource has limited rotary axis, closed contour geometry can lead to unwind situations depending on start point and process direction.  

RB_Turn

Use turn variants

Prevent unwind situations by selecting proper turn values for the first process point.

Limited to one turn value below and one above the default turn value.

 

Turn variants will be not considered, if the turn value is already set for the first process point.


The automatic process path optimization builds an optimized toolpath based on the incident validation at the toolpath positions and the via points on circular toolpath sections. It cannot prevent that in between these toolpath positions the trajectory still encounters some incident issue, because the trajectory itself cannot be evaluated.

With using the motion check of the data of the toolpath, the algorithm can define intermediate points between the toolpath positions and evaluate them for incidents. The quality evaluation on these intermediate points restricts for incidents on collision, reachability and singularity.

OLP_Toolpath_MotionCheck_Distance

Max. distance

The maximum Cartesian distance between two consecutive points to be checked.


OLP_Toolpath_MotionCheck_Angle

Max. angle

The maximum angular 'distance' between two consecutive points to be checked.



Toolpath quality is measured in costs. Incidents on toolpath positions, or between the positions normally increase these costs. The automatic optimization can identify the area of impact of these incidents. By trying to limit such area, the costs will reduce.

This can be achieved by adding, inserting additional process points on the toolpath around these critical areas.

OLP_Toolpath_InsertPoint

Insert process points

Switch to enable to insert additional process points.


OLP_Toolpath_InsertPointDistance

Minimum distance

The minimum Cartesian distance between two process points.

Measured between two inserted process points or between the inserted process point and an existing one.

OLP_Toolpath_InsertPointFactor

Minimum distance factor

The minimum distance as factor of the local process speed.

Measured between two inserted process points or between the inserted process point and an existing one.

Warning_24

The inserted process points belong to the automatic optimization data. This means that when running another optimization, removing the optimization data or anything else that causes a recomputation of the initial toolpath, these inserted process points will be deleted.



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