When we check the code, we can add a <robot> tag at the top of the description:
<?xml version="1.0"?> <robot name="pan_tilt">
The <robot> tag defines the name of the robot that we are going to create. Here, we named the robot pan_tilt.
If we check the sections after the <robot> tag definition, we can see link and joint definitions of the pan and tilt mechanism:
<link name="base_link">
<visual>
<geometry>
<cylinder length="0.01" radius="0.2"/>
</geometry>
<origin rpy="0 0 0" xyz="0 0 0"/>
<material name="yellow">
<color rgba="1 1 0 1"/>
</material>
</visual>
</link>The preceding code snippet is the base_link definition of the pan and tilt mechanism. The <visual> tag can describe the visual appearance of the link, which is shown on the robot simulation. We can define the link geometry (cylinder, box, sphere, or mesh...