You can import robots that have .stl files associated with the Unified Robot Description format (URDF) file to describe the visual geometries of the robot. Each rigid body has an individual visual geometry specified. The importrobot function parses the URDF file to get the robot model and visual geometries. The function assumes that visual geometry and collision geometry of the robot are the same and assigns the visual geometries as collision geometries of corresponsing bodies.

Use the show function to display the visual and collosion geometries of the robot model in a figure. You can then interact with the model by clicking components to inspect them and right-clicking to toggle visibility.

Import a robot model as a URDF file. The .stl file locations must be properly specified in this URDF. To add other .stl files to individual rigid bodies, see addVisual.

robot = importrobot('iiwa14.urdf');

Visualize the robot with the associated visual model. Click bodies or frames to inspect them. Right-click bodies to toggle visibility for each visual geometry.

show(robot,'visuals','on','collision','off');

Visualize the robot with the associated collision geometries. Click bodies or frames to inspect them. Right-click bodies to toggle visibility for each collision geometry.

show(robot,'visuals','off','collision','on'); 

Show different configurations of a robot created using a RigidBodyTree model. Use the homeConfiguration or randomConfiguation functions to generate the structure that defines all the joint positions.

Load example robots as RigidBodyTree objects.

load exampleRobots.mat

Create a structure for the home configuration of a Puma robot. The structure has joint names and positions for each body on the robot model.

config = homeConfiguration(puma1)

config=1×6 struct array with fields:
    JointName
    JointPosition

Show the home configuration using show. You do not need to specify a configuration input.

show(puma1);

Modify the configuration and set the second joint position to pi/2. Show the resulting change in the robot configuration.

config(2).JointPosition = pi/2;
show(puma1,config);

Create random configurations and show them.

show(puma1,randomConfiguration(puma1));

Use the Denavit-Hartenberg (DH) parameters of the Puma560® robot to build a robot. Each rigid body is added one at a time, with the child-to-parent transform specified by the joint object.

The DH parameters define the geometry of the robot with relation to how each rigid body is attached to its parent. For convenience, setup the parameters for the Puma560 robot in a matrix. The Puma robot is a serial chain manipulator. The DH parameters are relative to the previous line in the matrix, corresponding to the previous joint attachment.

dhparams = [0   	pi/2	0   	0;
            0.4318	0       0       0
            0.0203	-pi/2	0.15005	0;
            0   	pi/2	0.4318	0;
            0       -pi/2	0   	0;
            0       0       0       0];

Create a rigid body tree object to build the robot.

robot = rigidBodyTree;

Create the first rigid body and add it to the robot. To add a rigid body:

body1 = rigidBody('body1');
jnt1 = rigidBodyJoint('jnt1','revolute');

setFixedTransform(jnt1,dhparams(1,:),'dh');
body1.Joint = jnt1;

addBody(robot,body1,'base')

Create and add other rigid bodies to the robot. Specify the previous body name when calling addBody to attach it. Each fixed transform is relative to the previous joint coordinate frame.

body2 = rigidBody('body2');
jnt2 = rigidBodyJoint('jnt2','revolute');
body3 = rigidBody('body3');
jnt3 = rigidBodyJoint('jnt3','revolute');
body4 = rigidBody('body4');
jnt4 = rigidBodyJoint('jnt4','revolute');
body5 = rigidBody('body5');
jnt5 = rigidBodyJoint('jnt5','revolute');
body6 = rigidBody('body6');
jnt6 = rigidBodyJoint('jnt6','revolute');

setFixedTransform(jnt2,dhparams(2,:),'dh');
setFixedTransform(jnt3,dhparams(3,:),'dh');
setFixedTransform(jnt4,dhparams(4,:),'dh');
setFixedTransform(jnt5,dhparams(5,:),'dh');
setFixedTransform(jnt6,dhparams(6,:),'dh');

body2.Joint = jnt2;
body3.Joint = jnt3;
body4.Joint = jnt4;
body5.Joint = jnt5;
body6.Joint = jnt6;

addBody(robot,body2,'body1')
addBody(robot,body3,'body2')
addBody(robot,body4,'body3')
addBody(robot,body5,'body4')
addBody(robot,body6,'body5')

Verify that your robot was built properly by using the showdetails or show function. showdetails lists all the bodies in the MATLAB® command window. show displays the robot with a given configuration (home by default). Calls to axis modify the axis limits and hide the axis labels.

showdetails(robot)

--------------------
Robot: (6 bodies)

 Idx    Body Name   Joint Name   Joint Type    Parent Name(Idx)   Children Name(s)
 ---    ---------   ----------   ----------    ----------------   ----------------
   1        body1         jnt1     revolute             base(0)   body2(2)  
   2        body2         jnt2     revolute            body1(1)   body3(3)  
   3        body3         jnt3     revolute            body2(2)   body4(4)  
   4        body4         jnt4     revolute            body3(3)   body5(5)  
   5        body5         jnt5     revolute            body4(4)   body6(6)  
   6        body6         jnt6     revolute            body5(5)   
--------------------

show(robot);
axis([-0.5,0.5,-0.5,0.5,-0.5,0.5])
axis off

Load a robot model and modify the collision meshes. Clear existing collision meshes, add simple collision object primitives, and check whether certain configurations are in collision.

robot = loadrobot('kukaIiwa7','DataFormat','column');

for i = 1:robot.NumBodies
    clearCollision(robot.Bodies{i})
end

show(robot,'Collisions','on','Visuals','off');

collisionObj = collisionCylinder(0.05,0.25);

for i = 1:robot.NumBodies
    if i > 6 && i < 10
        % Skip these bodies.
    else
        addCollision(robot.Bodies{i},collisionObj)
    end
end

show(robot,'Collisions','on','Visuals','off');

figure
rng(0) % Set random seed for repeatability.
for i = 1:20
    config = randomConfiguration(robot);
    isColliding = checkCollision(robot,config);
    if isColliding
        show(robot,config,'Collisions','on','Visuals','off');
        title('Collision Detected')
    else
        % Skip non-collisions.
    end
end