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Tutorial: Building a Simple 2-Bar Robot - Robot Structure

In this tutorial, we will walk through the process of creating a simple "2-bar" robot. By following these steps, you will learn the basic workflow of robot creation, structure setup, and parameter configuration without getting bogged down in complex theories.

Goal: Create a 2-link robot named test_robot.

alt text
Conceptual Image of a 2-Bar Robot

Step 1: Create a New Robot

  1. Navigate to the Home screen.
  2. Click the Create New Robot button.
create_robot
Click the Create New Robot button
  1. In the setup screen:
    • Select EmptyRobot.
    • Enter the name: test_robot.
    • Click Create.
create_robot
Select EmptyRobot and name it test_robot

Step 2: Structure Setup (DH Parameters)

We will construct the skeleton of the robot by adding joints and setting their lengths.

1. Add Joints

  • Click the + button on the right side of the Joint Section to add two joints.

Enter the parameters as follows to create a 300mm link along the Y-axis:

  • Input Values:
    • Theta (θ) : 90 deg
    • D: 0 mm
    • A: 300 mm
    • Alpha (α) : 0 deg
    • Joint Type: Rotation Z
create_robot
Creation of Link 1

Set up the second link with the following values:

  • Input Values:
    • Theta (θ) : 0 deg
    • D: 0 mm
    • A: 300 mm
    • Alpha (α) : 0 deg
    • Joint Type: Rotation Z
create_robot
Creation of Link 2

4. Verify Movement

Use the Jog tab to ensure the joints rotate correctly.

  • Jog: Moves the robot.
  • Jog Reset: Returns the moved robot to its origin.
jog_control
Jog Control Interface

Step 3: Dynamics Configuration

Now we apply physical properties to the robot. For this tutorial, simply input the approximate values provided in the screenshots.

Note: For detailed definitions of Coordinate Systems and Mass calculations, please refer to the User Guide.

  1. Click Dynamics in the Joint Section.
  2. Enter the values for Mass, Center of Mass, and Inertia as shown below.
create_robot
Link 1 Inertia Settings
create_robot
Link 2 Inertia Settings

Step 4: Constraints Setup

Finally, we configure the safety limits and friction parameters.

  1. Click the Constraints button in the Joint Section.
  2. Match the settings in the images below for each joint.

Joint 1 Constraints

  • Input Values:
    • Lower Limit (θ): -180 deg
    • Upper Limit: 180 deg
    • Max Speed: 270 deg/s
    • Max Accel: 1,350 deg/s²
    • Max Jerk: 13,500 deg/s³
    • w1: 0 deg/s
    • f1: 0 Nm
    • w2: 0 deg/s
    • f2: 0 Nm
    • Max Friction: 0 Nm
    • Collision Threshold: 100 Nm
    • Join Goal Tolerance: 0.5729577951308232 deg
constraints
Constraints Settings for Joint 1

Joint 2 Constraints

  • Input Values:
    • Lower Limit (θ): -180 deg
    • Upper Limit: 180 deg
    • Max Speed: 412.5 deg/s
    • Max Accel: 2062.5 deg/s²
    • Max Jerk: 20,625 deg/s³
    • w1: 0 deg/s
    • f1: 0 Nm
    • w2: 0 deg/s
    • f2: 0 Nm
    • Max Friction: 0 Nm
    • Collision Threshold: 100 Nm
    • Join Goal Tolerance: 0.5729577951308232 deg
constraints
Constraints Settings for Joint 2

Summary

Congratulations! You have successfully:

  1. Created a robot skeleton using DH parameters.
  2. Applied dynamic properties.
  3. Configured safety constraints.

Your test_robot is now ready for simulation or control tasks. Proceed to Step 2: Robot System Parameters to configure the global robot parameters.