Path Planning Parameter Guide

Collision Detection

For detailed content, please see Collision Detection Configuration Guide.

Return Pose Type

The pose type of path points output by the planner, with options for Cartesian or joint.

Tool Binding

When multiple tools are added in the scene configuration, the motion planning panel will display the tool binding parameter item, listing all configured tools. When using motion planning in a multi-tool environment, tool binding operations must be performed to ensure that each grasping point is bound to a tool.

  1. Click the enter icon icon to the right of the tool name, and select the grasping points to be bound in the popup window.

  2. Click [Confirm].

Common Parameters for Grasping Path and Retraction Path

Number of Path Points

Path points are the basic components of a trajectory, with each path point containing information such as position and orientation.

  • Grasping Path

    For the grasping path, the number of path points includes all path points between the initial planning point and the pre-grasp point, as well as the final grasping point. It minimally includes the "starting point", "pre-grasp point", and "grasping point", so the minimum value is 3.

  • Retraction Path

    For the retraction path, the number of path points includes all path points between the pre-retraction point and the retraction endpoint, as well as the grasping point. It minimally includes the "grasping point", "pre-retraction point", and "retraction endpoint", so the minimum value is still 3.

The number of path points affects the fineness and accuracy of the trajectory: the more points, the more detailed the trajectory and the higher the path reliability, but the planning time will also increase accordingly. When the grasping path and retraction path are longer, it is recommended to increase the number of path points; when the paths are shorter, the number can be reduced. The final value can be adjusted according to the actual project requirements.

When planning the retraction path, the final number of path points will be twice the set number of path points.

Joint Angle Difference Threshold

The joint angle difference threshold is used to set the maximum angle range allowed for a single joint to change between two adjacent path points, limiting joint angle differences to avoid large changes in the robot’s pose and make the path smoother. If the threshold is exceeded during the actual planning process, it will report that the path point is unreachable.

Motion Planner

What is a Motion Planner?

A planner is an algorithm used for path planning, used to find a feasible path from a starting point to an endpoint in a given space.

Planner Types

Select a planner from the dropdown list on the right. Motion planners include the following options:

  • Joint Space Planner

    The joint space planner performs path planning directly in the robot’s joint space. Key features include:

    • Precise control: Suitable for precise control of robot joints.

    • Complexity: In high-dimensional joint spaces, searching may be relatively complex.

    • Applicability: Suitable for applications requiring precise joint movement, such as robotic arms.

  • Linear Planner

    The linear planner plans paths along straight lines, typically used for simple linear movements. Key features include:

    • Simple and fast: Suitable for simple environments, with fast computation speed.

    • Straight-line paths: Generates straight-line paths, suitable for environments without obstacles.

    • Limitations: Not suitable for path planning in complex environments.

  • Bézier Curve Planner

    The Bézier curve planner uses Bézier curves to generate smooth paths. Key features include:

    • Smooth paths: Generates smooth paths, suitable for applications with path smoothness requirements.

    • Complex calculation: Higher computational complexity, suitable for precise control and environments requiring smooth paths.

    • Flexibility: Able to generate curved paths of various shapes.

Planner Parameter Description

  • Bézier Curve Planner Parameters

    • Starting Point Curvature

      Starting point curvature refers to the curvature value of the Bézier curve at the starting point in path planning. The starting point curvature determines the degree of curvature when the robotic arm begins to move from its initial position. A higher parameter value indicates a greater degree of curvature.

    • Target Point Curvature

      Target point curvature refers to the curvature value of the Bézier curve at the endpoint in path planning. The target point curvature determines the degree of curvature when the robot approaches the target position. A higher parameter value indicates a greater degree of curvature.

Other Grasping Path Parameters

What is a Grasping Path Starting Point?

The starting position for planning a path, representing the initial state of the robot or gripper before movement begins. It includes position and posture information to enable planning a safe and collision-free path.

Adding a Grasping Path Starting Point

  1. The pose of the grasping path starting point cannot be set directly through its own parameters but must be achieved by setting the robot pose. When adding a grasping path starting point, you can first set the robot pose:

    1. Open the parameter settings panel, open the robot tool controller in the robot parameters, and select a tool.

    2. Hold the Shift key and drag the controller with the left mouse button to move it to the target position. Click the update scenes points icon on the right side of the path point in the path planning panel to update the starting point pose.

  2. Add a grasping path starting point:

    1. Click + on the right side of the grasping path starting point entry.

    2. Enter a name for the grasping path starting point in the popup window, click Confirm, and the grasping path starting point will be generated at the TCP location.

      alt

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      Before generating the starting point

      After generating the starting point

      Additionally:

      To set multiple starting points, reset the robot pose and then add a starting point. The new starting point will be generated at the TCP location; if the robot pose is not modified, the new starting point will overlap with the original starting point.

  3. Set the grasping path starting point model parameters (optional).

    • Click the set attribute icon to the right of the grasping path starting point name.

    • In the Details popup, you can rename the grasping path starting point, modify its color, set its size, opacity, and coordinate axis length, and view the starting point’s pose information.

      Additionally:

      1. To adjust the starting point pose, you need to reset the robot pose and then click the update scenes points icon to update the starting point pose to the robot’s TCP.

      2. If you do not need to adjust the starting point pose, you can click the robot move points icon icon to move the robot model to that starting point.

      3. To delete the starting point, click the delete icon icon to the right of the starting point name.

What is a Pre-Grasp Point?

A pre-grasp point is an intermediate posture position for the robotic arm before reaching the final grasping target position. It is typically set at the top of the material box or at a user-defined safe position. The purpose is to ensure that the robot can approach the target object along a safe and efficient path, avoiding collisions with the surrounding environment.

Adding Pre-Grasp Points

  1. Click + on the right side of the pre-grasp point entry.

  2. Enter a name for the pre-grasp point in the popup window, adjust the offset direction, offset distance, and collision detection step size, then click Confirm.

    • Offset Distance: As shown in the figure below: ① is the grasping point, ② is the pre-grasp point, and ③ is the offset distance.

    pick path plan prepick distance

    • Offset Direction:

    Method

    Axis

    Along Grasping Point

    X+, X-, Y+, Y-, Z+, Z-

    Along Robot Coordinate System

    X+, X-, Y+, Y-, Z+, Z-

    Custom Direction

    X, Y, Z

    • Custom Direction: X/Y/Z component setting explanation

    Parameter Value

    Description

    0

    No offset in this direction.

    1

    Offset in the positive direction.

    -1

    Offset in the negative direction.

    The pre-grasp point (②) shown in the figure above has X and Y set to 0, and Z set to -1.

    Additionally:

    • To set pre-grasp point parameters, click the set attribute icon to the right of the pre-grasp point name.

    • To delete the pre-grasp point, click the delete icon icon to the right of the pre-grasp point name.

Other Retraction Path Parameters (Optional)

What is a Pre-Retraction Point?

A pre-retraction point is an intermediate posture position for the robotic arm after reaching the grasping target position. It is typically set at the top of the material box or at a user-defined safe position to plan a collision-free path from the pre-retraction point to near the retraction path end point.

Adding Pre-Retraction Points

For the operation process, please refer to Adding Pre-Grasp Points.

What is a Retraction Path End Point?

The end position in the retraction path planning algorithm, representing the final state of the robot or gripper carrying the workpiece. It includes position and posture information to enable planning a safe and collision-free retraction path.

Adding Retraction Path End Points

The pose of the retraction path end point is the same as the grasping path starting point. It cannot be set directly through its own parameters but must be achieved by setting the robot pose.

For the operation process, please refer to Adding a Grasping Path Starting Point.