Relative Move

Function

This Step guides the robot to move relative to other waypoints.

Usage Scenario

This Step is usually used before and after the picking and placement, avoiding collisions by offsetting the waypoint in the Z-direction of the pick point and placing waypoint.

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.

Collision Avoidance

This parameter group is only visible in the Developer mode.
Enable Collision Avoidance

The waypoint corresponding to the current Step is used as the center, and multiple alternative waypoints are added around it. In this way, the robot has more alternative paths during the planning process to effectively avoid obstacles, which also reduces project tuning difficulty and enhances the success rate of the path planning.

Avoidance Range Radius

The alternative waypoints will be generated within the sphere with the set value as the radius.

TCP Angle Adjustment Range

The angle adjustment range of the TCP at the alternative waypoint.

move angle adjust range

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.
This motion type is applicable to scenarios where the requirement of path accuracy is not strict and the robot moves in a large space.

Linear move

Linear motion, which guides the robot to move linearly.
This motion type is applicable to scenarios where there is a strict requirement for path accuracy, such as welding, gluing, and certain types of picking.

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

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

  • The waypoints are more evenly distributed and the number is controlled.

  • Applicable to Standard Interface communication.

  • The success rate of path planning is higher.

  • Only move to the required number of waypoints.

Disadvantages

  • If the number of motion segments is set too much, the robot will jam and slow down.

  • Setting the number of segments manually may slightly increase the probability of avoidance failure.

  • The waypoints may be unevenly distributed.

  • Not available for Standard Interface communication.

Parameter Description

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.

  • 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.

  • 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.

Movement mode

Conventional relative move

Relative to the reference point, translate along the X/Y/Z axis of the tool reference frame or robot reference frame.

Move to a specified plane

Relative to the reference point, translate along the X/Y axis of the tool reference frame or robot reference frame, ultimately reaching the plane at the specified height. The orientation of the target waypoint is the same as the reference point.

Move to a specified position

Relative move to a specified position. The reference point only provides orientation information for the target waypoint. During the robot’s movement between the reference point and the target waypoint, the robot’s TCP does not rotate.

Conventional relative move

Reference point

Calculate the actual waypoint that will be reached in the current Step based on the reference point.

Reference frame

Select the reference frame that defines the movement direction.

Translation distance

Specify the translation distance along each axis.

Relative rotation

It is not checked by default. When enabled, you can specify the relative rotation between the target waypoint and the reference point.

Move to a specified plane

Reference point

Calculate the actual waypoint that will be reached in the current Step based on the reference point.

Reference frame

Select the reference frame that defines the movement direction.

Height of plane

The height of the specified plane.

Relative translation distance

It is not checked by default. When enabled, you can specify the distance the robot moves along the X-axis or Y-axis relative to the reference point in the reference frame.

Move to a specified position

Reference point

Select the waypoint that provides the pose orientation information for the target waypoint.

Specified position

Specify the position of the target waypoint in the robot reference frame.

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