DH Table Visualization

IRBCAM Tutorial
1

This tutorial shows the use of the Denavit-Hartenberg (DH) Table feature in IRBCAM. This feature is available for educational purposes to help users understand the DH convention in an interactive way. Moreover, this tutorial also demonstrates how the robot represented by the DH Table can be imported into IRBCAM. IRBCAM uses analytical inverse kinematics (IK) solutions for specific brands, eg., ABB, KUKA, MOTOMAN, etc. However, a numerical IK solver is used for solving the IK of robot described by the DH table.

In IRBCAM, both modified (default) and classical/standard DH parameters can be used in the DH table. In this tutorial, classic DH parameters are used. The following notations are used in DH table editor:

Type - Joint type (revolute, prismatic, or fixed)

Min - Minimum joint limit (in degrees for revolute joints and in mm for prismatic joints)

Max - Maximum joint limit (in degrees for revolute joints and in mm for prismatic joints)

\theta_{i} - Rotation about the moving Z-axis

d_{i} - Translation about the moving Z-axis

\alpha_{i} - Rotation about the moving X-axis

a_{i} - Translation about the moving X-axis

So the resulting transformation between successive frames is given by

^{i-1}T_{i} = R_z(\theta_{i})T_{z}(d_{i}) R_{x}(\alpha_{i})T_{x}(a_{i})

Creating DH Table

  1. First, open DH Table editor: Edit > DH Table

  2. Then enable Use Classic Parameters checkbox to use classic DH parameters. Leave it unchecked to use the modified DH parameters.

  3. Click ADD ROW/JOINT to add a row/joint in the DH table.

  4. Update the Type, Min, Max, \theta_{i}, d_{i}, \alpha_{i}, a_{i} based on the robot kinematic description.

  5. Repeat steps 3 - 4 to add all joints until the tip of the robot.

  6. The robot joints, links, axes and coordinate frames are visualized in the scene.

  7. The Visualization Settings can be used to change the width of links/joints/axis and to show/hide joint/base coordinate frames.

  8. Once all rows are added, click UPLOAD ROBOT to upload the robot described by the DH Table.

  9. Once the robot is uploaded, this robot is loaded in the scene/project and can be used in IRBCAM similar to other available robots. The only difference is that the robot described by the DH Table will use the numerical IK solver instead of analytical solutions.

  10. The DH Table sidebar can be closed after this. The uploaded robot defined by the DH Table can be imported into IRBCAM as: Edit > Robot > User Created > Select your robot