Planning This article covers several ways of adjusting operations to avoid collisions for simultaneous multi-robot work areas. (Potentially an in-depth walkthrough?)
Manual methods of mitigating collisions for multi-robot simultaneous.
Procedure on how to rearrange and change path directions to avoid multi-robot collisions.
Rearrange → Device Side
Timing
Use the scheduler to
Change the sequence of operations
Move operations from one robot to another
Change path direction
A dome in work cells with multiple robots.
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As an example, a dome-shaped part requires edge following operations on five contours.
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These operations will be distributed between two separate robots and processed simultaneously.
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In some cases, the default robot trajectories for the multiple robots may result in collisions between the robots.
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There are many ways to solve collisions between robots. Let’s take a look at a few possible solutions.
Move start point
Operations 1 and 2 are processed by different robots, and there
Rearrange operations for a robot
One way of solving collisions is to change the sequence in which operations are performed for a given robot.
In this example, Robot_1 is processing operations 1 and 2, and Robot_2 is processing operations 3, 4, and 5:
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There is a collision between the toolings joints of the different robots when operations 1 and 3 are processed.
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The proximity of the entry/exit points on the operations causes a collision.
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There are multiple ways to solve this issue in Robotmaster:
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Add a wait time to one of the operations, so that the end-of-arm toolings aren’t in that space at the same time.
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This is due to the proximity and timing of the two paths.
The sequence of Robot_2 could be changed so that operation 4 is processed first. This would leave more space between Robot_1 and Robot_2 as the operations are executed, lessening the chance of a collision.
Use the control handle to drag the operation to a different place in the sequence.
Select Calculate to see if the collision is cleared.
Rearranging the sequence of operations will also affect robot motion, including moves to and from home position and moves between operations. Pay attention to these changes and resolve any kinematic issues if they arise.
Reassign operations to different robots
If multiple robots use the same application (for example, if they are both equipped with interchangeable deburring tools), reassigning operations to different robots can solve collisions.
Use the control handle to drag the operation to a different robot.
Adjust the sequence of operations for that robot, if needed.
Select Calculate to see if the collision is cleared.
Move start point
In some cases, moving the entry/exit point on one of
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Change the sequence of operations for one of the robots.
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Assign certain operations to different robots
Change cut direction
Notes:
Rearranging operations in the Device > Operations pane.
Change sequence of operations within a given robot
Move operations from one robot to another
Change Path Directions → Task Side
Change path direction
Change start point of path
Further reading
What about velocities, accelerations, and real-world deviation from programmed paths?
Use safety envelopes to give “buffer” for collisions, add them as intereference groups in the cell.
Do multiple robot cells communicate with one another? Are they equipped with sensors to detect adjacent robot position?
Spatial
If you plan a progam so that the robots never occupy the same space at any point in time, this is the safest with least chance of collision.
Temporal
If two robots must occupy the same space due to the required trajectories, timing the operations is critical for minimizing risk of collisions.
How much time to leave between operations' intersections in space? 1 second, 30 seconds?
What is the typical difference between ideal vs actual speed due to acceleration, payload, and whatever else might factor in?the paths may solve a collision. This can affect timing so that robots do not collide.
On the Device tab, in the Operations pane, right-click an operation and select Edit in task.
Select the path, then click the red ball at the entry/exit point.
Click a point along the path to move the entry/exit to a different location.
On the Task tab, select Apply and then OK to keep your changes.
On the Device tab, select Calculate.
Check to see if the collision still occurs.
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Change path direction
For applications where it is possible to change the direction of a path, you can try reversing path direction to solve collisions.
On the Device tab, in the Operations pane, right-click an operation and select Edit in task.
Right-click the path (be sure to right-click one of the vectors on the path), then select Path > Invert direction.
Confirm that the path direction is reversed.
On the Task tab, select Apply and then OK to keep your changes.
On the Device tab, select Calculate.
Do not use this method for applications where path direction should not reversed, such as with plasma cutting.