Adaptive Relative Move
Function
This Step adaptively adjusts the distance to a reference point based on the height of the held target object.
Usage Scenario
The lifting distance when the “Relative Move” Step is used is fixed, while the “Adaptive Relative Move” Step can adjust the lifting distance according to the box height. The box height is obtained from the vision result output by Mech-Vision.
Depalletizing Scenario
In depalletizing scenarios, to ensure that all boxes can be safely picked, the lifting distance should be set according to the dimensions of the largest box. As shown in the figure below, the lifting distance in the Z-direction is denoted by h1, i.e., boxes of all dimensions will be lifted by h1. When depalletizing smaller boxes as shown below, the box needs to be lifted by h2 ideally. However, the software will still guide the robot to lift the box by h1, which brings extra movement of the robot and affects the takt time and robot flexibility.
Once this Step is used, the lifting distance can be adjusted dynamically according to the box height, which reduces extra movement, upgrades the takt time of the robot motion, and prevents the robot from moving to unreachable waypoints.
Placement Scenario
After the boxes are picked, they may need to be placed on the conveyer belt. Since the pick points of the boxes are located on the upper surface of the boxes, the robot will release the held boxes at the same height and cannot adjust the placing positions according to the height of the held box, regardless of whether the waypoint type is TCP or target object pose.
Once this Step is used, the box height will be added to the height for placing the box, and therefore the placing position can be adjusted.
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Fixed placing positions |
Placing positions after adding the box heights |
Parameter Description
Move-Type Step Common Parameters
Send Waypoint
Selected by default, i.e., send the current waypoint to the receiver, such as the robot. Once deselected, the current waypoint will not be sent. However, the waypoint will remain in the planned path.
Try Continuously Running through Succeeding Non-Moves
Unselected by default. When non-move Steps, such as Visual Recognition, Set DO, Check DI, etc., are connected between move-type Steps, the sending of the waypoints will be interrupted, and the real robot will take a short pause, reducing the smoothness of running.
When this parameter is selected, the project will continue to run without waiting for the current move-type Step to complete execution, and therefore the robot can move in a smooth way without pauses. However, selecting this parameter may cause the execution of the Step to end prematurely.
Why will this feature cause the execution of the Step to end prematurely?
Mech-Viz will send multiple waypoints simultaneously to the robot when the project is running. When the currently returned JPs of the robot correspond to the last waypoint sent by Mech-Viz, Mech-Viz will assume that the robot has moved to the last waypoint.
For example, there are 10 move-type Steps in a path, and the pose of the 5th move-type Step is the same as that of the last move-type Step. When the robot moves at a low speed, the current JPs will be sent to Mech-Viz after the robot moves to the 5th waypoint. Since the poses of the 5th move-type Step and the last move-type Step are the same, Mech-Viz may mistakenly determine that the robot has reached all waypoints and prematurely ends the command.
Do Not Check Collision with Placed Target Object
Once Detect collisions on target objects is enabled in the Collisions panel, selecting this parameter will disable the collision detection between the robot, robot tool, and placed target objects. Typically, this parameter is selected in the move-type Step following the Step whose Pick or place is set to Place to avoid false collision detections.
Application Example:
The TCP of a depalletizing vacuum gripper is usually set inside the model rather than on the surface of the vacuum gripper. As a result, when picking a box, the vacuum gripper model may overlap with the box model. However, the software does not detect collisions between the end tool and the picked target object, so no collision alarm will be triggered during picking. Once the robot places the box down, the picked box model becomes a scene model, and the software will start to detect the collision between the end tool and the box’s scene model, triggering a collision alarm and preventing the completion of the palletizing task.
Once this parameter is selected, no collision between the robot, end tool, and the model of the placed target object will be detected, and the above issue will be resolved.
Point Cloud Collision Detection Mode
Usually, Auto can be selected, i.e., directly apply the Point cloud collision detection settings in the Collisions panel. For the Steps between picking and placing, Check collision can typically be selected.
Auto |
Default setting. Once Detect collisions on target objects is enabled in the Collisions panel, only point cloud collisions of the “Vision Move” Step and the “Relative Move” Steps that depend on the “Vision Move” Step will be detected, while other move-type Steps will not be detected. |
Do not check collision |
Point cloud collisions of all move-type Steps will not be detected. |
Check collision |
Point cloud collisions of all move-type Steps will be detected. |
Ignore Target Object Symmetry
This parameter is only visible when the Waypoint type of the move-type Step is set to Target object pose.
The target object symmetry here refers to the Rotational symmetry of held target object predefined in the target object editor during collision model setup.
None |
Default setting, i.e., do not ignore symmetry on any axis. |
Around target object frame Z axis |
Only ignore symmetry around the Z-axis. |
Around target object frame X&Y axes |
Ignore symmetry around the X-axis and Y-axis. |
Around all axes |
Once the symmetry around all axes is ignored, the robot will place the object strictly according to the target object pose. |
| When the move-type Steps are used to place the target objects, the consistency of the placing poses of the target objects cannot be guaranteed once the rotational symmetry is applied. If you want all target objects to be placed strictly according to a specific rule, ignore the symmetry of the target object around all axes. |
Plan Failure Out Port
Once this parameter is selected, a Plan failure exit port will be added to the Step.
If the path planning of the current Step succeeds, the workflow will continue along the Success exit port. If the path planning of the current Step fails, the workflow will proceed along the Plan failure exit port. If multiple move-type Steps with “Plan failure” exit ports display in the same plan history entry, the workflow will proceed along the “Plan failure” exit port of the first move-type Step.
Held Target Object Collision Detection Settings
Before configuring this parameter group, please go to the Collisions panel and enable Detect collisions on target objects.
| Disabling collision detection will increase the collision risks. Please select the following parameters with caution. |
Do Not Check Collision with Scene Objects
Once this parameter is selected, collisions between the held target object and the scene model will not be detected, reducing the computational load of collision detection in the software, speeding up path planning, and optimizing the overall cycle time.
Do Not Check Collision with Robot
Once this parameter is selected, collisions between the held target object and the robot will not be detected, reducing the computational load of collision detection in the software, speeding up path planning, and optimizing the overall cycle time.
Do Not Check Collision with Point Cloud
Once Point cloud collision detection is enabled in the Collisions panel, selecting this parameter will stop detecting collisions between the held target object and the point cloud, further reducing the software’s computational load, shortening path planning time, and enhancing the overall cycle time.
Basic Move Settings
Motion type
Joint move |
Joint motion, which guides the robot to move in a curved path. It is less likely to reach singularities in the path for joint motion.
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Linear move |
Linear motion, which guides the robot to move linearly.
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Singularity Avoidance
When the motion type is Linear move, enabling this function can simulate linear move by joint move with multiple segments, thus reducing singularity problems to a certain extent.
Parameters Setting
| Limit to Motion Segments | Specific Number | No Limit |
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Feature |
Simulate linear move using joint move with a user-specified number of segments. |
The software calculates the number of segments needed to simulate linear move. |
Advantages |
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Disadvantages |
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| Parameter | Description |
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Number of Segments |
The number of joint move segments specified by the user when the Limit to Motion Segments is set to Specific Number. |
Max Position Deviation |
The maximum allowable deviation of the new multi-segment joint motion path from the original linear motion path. The greater the max position deviation, the higher the success rate of singularity avoidance, and the lower the similarity between the actual trajectory and the straight line. |
Max Angle Deviation |
The maximum allowable angular deviation of the new multi-segment joint motion path from the original linear motion path. The greater the max angle deviation, the higher the success rate of singularity avoidance, and the lower the similarity between the actual trajectory and the straight line. |
Velocity & Acceleration
Velocity and acceleration determine how fast the robot can move. Usually, the set acceleration should be lower than the velocity. When the set acceleration is higher than the velocity, the robot will move in a choppy way.
| The velocities of Vision Move and its prior and subsequent Steps should be relatively low to ensure that the objects can be picked steadily. |
Blend radius
Usually, the default setting can be used.
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The blend radius refers to the distance between the target point and the point where the robot starts to turn. The larger the blend radius, the more smoother the robot motion transitions are. If the robot moves in a relatively small space, please set the blend radius to a smaller value.
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If the robot moves in a relatively large space without obstacles and the distance between two consecutive path segments is long, please set the blend radius to a larger value.
Reference point
The reference point for the adaptive relative move, which will be used as the starting position in the calculation of the offset, and therefore the target waypoint of this Step can be generated.
Previous waypoint is usually selected after picking. |
Next waypoint is usually selected after placing. |
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Relative move offset
You need to specify the Offset direction and Fixed offset to determine the offset here.
This Step supports setting the offset along the Z-direction of the reference point represented in the form of tool pose or along the Z-direction in the world frame.
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Illustration of the world frame and the tool frame of the reference point (assuming that the pick point is set to the reference point): 
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Tool pose Z-direction of reference point: Set the offset along the Z-direction of the reference point represented in the form of tool pose.
Relative move offset = Fixed offset - Target object height in the Z-direction
Since the Z-axis of the tool pose usually points to the ground, it is recommended to set Fixed offset to a negative value to add a height and lift the box successfully. Then the robot end tool will offset along the negative Z-direction in the tool frame by the distance of |Fixed offset| plus the box height in the Z-direction.
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World frame Z-direction: Set the offset along the Z-direction in the world frame.
Relative move rotation = Fixed offset + Target object height in the Z-direction
Since the Z-axis of the world frame usually points upwards, it is recommended to set Fixed offset to a positive value. Then the robot end tool will offset along the positive Z-direction in the world frame by the distance of Fixed offset plus the box height in the Z-direction.
