Is it possible to show and control two interactiveRigidBodyTree in the same Figure?

Hello everybody,

I'm designing a robotic solution that comprises two ur3e arms with different poses and using the robotics toolbox I do not manage to represent the two interactiveRigidBodyTree of each arm in the same Figure. So far I have managed to load both robots into a single figure but just as a representation, without the possibility to control the arms interactively. Is there a workaround to represent and control both arms in the same Figure?

Thank you in advance for your help!

Answer 1

[Karan Singh]

Hi Virgilio,

From what I understand, the goal is to represent and control both arms in the same figure using the Robotics Toolbox in MATLAB.

Yes, there is a solution to represent and control both UR3e arms in the same figure using the Robotics Toolbox in MATLAB. Here's a possible approach:

1. Create separate “interactiveRigidBodyTree” objects for each UR3e arm. Let's say you have “robot1” and “robot2” representing the two arms.
2. Create a single figure to display both arms using the “figure” command in MATLAB.
3. Use the “axes” command to create two separate axes within the figure, one for each arm.
4. Set the “Parent” property of each “interactiveRigidBodyTree” object to the respective axes.
5. Now you can control each arm interactively by manipulating the joint angles or end effector poses using the “interactiveRigidBodyTree” objects “robot1” and “robot2”.

Here's an example of how you can modify the code to achieve this:

% Import the necessary classes from the Robotics Toolbox 
import robotics.* 
import robotics.manip.internal.* 

% Create two UR3e robot models 
robot1 = importrobot('ur3e.urdf'); 
robot2 = importrobot('ur3e.urdf'); 

% Create separate interactiveRigidBodyTree objects for each robot 
irt1 = interactiveRigidBodyTree(robot1); 
irt2 = interactiveRigidBodyTree(robot2); 

% Create a figure to display both arms 
figure('Name', 'Dual UR3e Arms'); 
ax1 = axes('Parent', gcf, 'Position', [0.05, 0.1, 0.4, 0.8]); 
ax2 = axes('Parent', gcf, 'Position', [0.55, 0.1, 0.4, 0.8]); 

% Set the Parent property of each interactiveRigidBodyTree object to the respective axes 
irt1.Parent = ax1; 
irt2.Parent = ax2; 

% Set initial joint angles for each arm 
jointAngles1 = zeros(1, 6); 
jointAngles2 = [pi/4, -pi/4, pi/3, -pi/2, pi/4, 0]; 
irt1.setJointPosition(jointAngles1); 
irt2.setJointPosition(jointAngles2); 

% Control the arms interactively 
while true 
    % Get user input for joint angles or end effector poses 
    jointAngles1 = input('Enter joint angles for arm 1: '); 
    jointAngles2 = input('Enter joint angles for arm 2: '); 
    
    % Set the joint angles for each arm 
    irt1.setJointPosition(jointAngles1); 
    irt2.setJointPosition(jointAngles2); 
    
    % Update the figure to reflect the new arm configurations 
    drawnow; 
end 

Attached below are some documentation links that you may find helpful:

• Interact with rigid body tree robot models - MATLAB (mathworks.com)
• Create Cartesian axes - MATLAB axes (mathworks.com)
• Update figures and process callbacks - MATLAB drawnow (mathworks.com)
• Create figure window - MATLAB figure (mathworks.com)

Hope this helps!

Karan Singh Khati