Why doesn't my URDF joints appear for tweaking wihtin RViz

Course Support URDF for Robot Modeling
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1

Firstly, i’d like to say that the code runs fine, but the robot does not do what it’s supposed to do. But thats not my question.

The question is: Why are the pitch_joint and yaw_joint joints in my joint_state_publisher missing in Rviz? This is my current code:

<?xml version="1.0"?> 
<link name = "roll_link">
    <origin rpy="0 0 0" xyz="0 0 0"/>
    <geometry>
        <cylinder radius="0.002" length="0.001"/>
    </geometry>
</link>

<joint name="roll_joint" type="revolute">
    <parent link = "base"/>
    <child link = "roll_link"/>       
    <origin rpy="0 0 0" xyz="0 0 0"/>
    <limit lower="-0.2" upper="0.2" effort="0.1" velocity="0.005"/>
    <axis xyz = "1 0 0"/>
</joint>

<link name = "pitch_link">
    <origin rpy="0 0 0" xyz="0 0 0"/>
    <geometry>
        <cylinder radius="0.002" length="0.001"/>
    </geometry>
</link>

<joint name="pitch_joint" type="revolute">
    <parent link = "roll_link"/>
    <child link = "pitch_link"/>       
    <origin rpy="0 0 0" xyz="0 0 0"/>
    <limit lower="0.2" upper="0.2" effort="0.1" velocity="0.005"/>
    <axis xyz = "0 1 0"/>
</joint>


<link name = "yaw_link">
    <origin rpy="0 0 0" xyz="0 0 0"/>
    <geometry>
        <cylinder radius="0.002" length="0.001" />
    </geometry>
</link>

<joint name="yaw_joint" type="revolute">
    <parent link = "pitch_link"/>
    <child link = "yaw_link"/>       
    <origin rpy="0 0 0" xyz="0 0 0"/>
    <limit lower="0.2" upper="0.2" effort="0.1" velocity="0.005"/>
    <axis xyz = "0 0 1"/>
</joint>    

<link name= "head">
    <visual>
        <origin rpy="0 0 0" xyz="0 0 0"/>
        <geometry>
            <sphere radius="0.06"/>
        </geometry>
    </visual>
</link>

<joint name="head_joint" type="revolute">
    <parent link="yaw_link"/>
    <child link="head"/>
    <origin xyz="0 0 0.06" rpy="0 0 0"/>
    <limit lower="-0.2" upper="0.2" effort="0.1" velocity="0.005"/>
    <axis xyz="1 0 0"/>
</joint>

<link name="left_eye">
    <visual>
        <origin xyz="0 0 0" rpy="0 0 0"/>
        <geometry>
            <cylinder length="0.005" radius="0.005"/>
        </geometry>
    </visual>
</link>

<link name="right_eye">
    <visual>
        <origin xyz="0 0 0" rpy="0 0 0"/>
        <geometry>
            <cylinder length="0.005" radius="0.005"/>
        </geometry>
    </visual>
</link>

<joint name="l_eye_joint" type="fixed">
    <parent link="head"/>
    <child link="left_eye"/>
    <origin xyz = "0.06 0.01 0" rpy="0 1.5707 0"/>
</joint>

<joint name="r_eye_joint" type="fixed">
    <parent link="head"/>
    <child link="right_eye"/>
    <origin xyz = "0.06 -0.01 0" rpy="0 1.5707 0"/>
</joint>

And this is what i see in RViz:

image
image1296×698 121 KB

Only the roll_joint and head_joint are displayed in Rviz even though i explicitly defined the other joints within my URDF code. Pls help, thanks!

2

Ok anyway i solved it. It was a really silly mistake that cost me hours trying to figure out. I realised it was because i was careless and forgot to put a negative sign in the “limit lower” field inside the “yaw_joint” and “head_joint” causing it not to appear in the RViz

3

Glad that you solved it! Also thanks for sharing the solution here so that it can help other users that face the same issue.