Insert_block in xacro-macro

Course Support URDF for Robot Modeling
1

Hi,
In 5-XACRO Basis of URDF course, when we create urdf-file with xacro-file, we have this part:

<xacro:macro name="gurdy_leg" params="headlink_name number colour *origin">

    <xacro:upperleg_link number="${number}"/>
    <xacro:upper_transmission number="${number}"/>

    <joint name="head_upperlegM${number}_joint" type="revolute">
        <parent link="${headlink_name}"/>
        <child link="upperleg_M${number}_link"/>
        
        <xacro:insert_block name="origin" />
        <limit lower="-1.55" upper="0.0" effort="1.0" velocity="0.005"/>
        <axis xyz="0 1 0"/>
    </joint>
    
    <xacro:lowerleg_link number="${number}"/>
    <xacro:lower_transmission number="${number}" number_transm="${number + 3}"/>

    <xacro:foot_link number="${number}" colour="${colour}"/>

</xacro:macro>

This is version only with upperleg and lowerleg.

There is another more complicate model from “gurdy” exercise, which adds yaw joints between head_link and upperleg_link. So we have yaw_joints. The problem is: in simple model, we need insert_block because the position and orientation of “head_upperlegMi_joint” are different.

But in complicate model, we have 2 parts with different positions and orientations:

“head_upperlegMi_yaw_joint” and “head_upperlegMi_joint”.

As a result, I need to give 2 “insert_block” with same tag “origin”. But how can I actually achieve that? What is the syntax? I have tried this, but wrong:

<xacro:macro name="gurdy_leg" params="head_link_name Number Color *origin *origin">  
<!-- *upperleg_joint_origin -->

    <!-- apply yaw link -->
    <xacro:upperleg_yaw_link number="${Number}"/>

    <!-- define yaw joint -->
    <joint name="head_upperlegM${Number}_yaw_joint" type="revolute">
        <parent link="${head_link_name}"/>
        <child link="upperleg_M${Number}_yaw_link"/>
        <!-- origins of yaw joints are different, so here to individually define, as an insert_block -->
        <xacro:insert_block name="origin"/>
        <limit lower="-0.7" upper="0.7" effort="1.0" velocity="0.005"/>
        <axis xyz="0 0 1"/>
    </joint>

    <!-- apply transmission of yaw joint -->
    <xacro:trans_yaw number="${Number}"/>

    <!-- apply upperleg link -->
    <xacro:upperleg_link number="${Number}"/>

    <!-- define upperleg joint -->
    <joint name="head_upperlegM${Number}_joint" type="revolute">
        <parent link="upperleg_M${Number}_yaw_link"/>
        <child link="upperleg_M${Number}_link"/>
        <xacro:insert_block name="origin"/>
        <limit lower="-1.55" upper="0" effort="1.0" velocity="0.005"/>
        <axis xyz="0 1 0"/>
    </joint>

    <!-- apply transmission of upperleg joint -->
    <xacro:trans_upperleg number="${Number}"/>

</xacro:macro>

So how can I insert multiple blocks with same tag into a “macro”? Can anyone share an example of how to do that? Or is it actually possible to do so?

Thank you

2

HI,

In theory you should be able to us the origin in multiple places, but if you could share your xacro file here, we could have a look and test it.

3

Hi @duckfrost2
Here is my file. The main difference is that I only add jaw joint between head_link and upperlegs, without the “prismatic joints” on foot_links. And the way I tried to insert 2 “insert_block” is in macro of “gurdy_leg”, which contains " *origin1 " and " *origin2 " (line 263). And apply them with 2 tag “origin1” and “origin2” (line346-356).

<?xml version="1.0"?>

(sorry it shoud contain this:
robot xmlns:xacro=“http://www.ros.org/wiki/xacro” name=“gurdy”
but I don’t know why it cannot show when I sometimes add <>)

<xacro:macro name="gurdy_head" params="">

    <link name="base_link">
        <collision>
            <origin xyz="0 0 0" rpy="0 0 0"/>
            <geometry>
                <box size="0.01 0.01 0.01"/>
            </geometry>
        </collision>
        <visual>
            <origin xyz="0 0 0.01" rpy="0 0 0"/>
            <geometry>
                <box size="0.01 0.01 0.01"/>
            </geometry>
        </visual>
    </link>

    <link name="head_link">
        <inertial>
            <origin xyz="0 0 0.02" rpy="0 0 0"/>
            <mass value="0.01" />
            <inertia ixx="7.58333333333e-07" ixy="0.0" ixz="0.0" iyy="7.58333333333e-07" iyz="0.0" izz="1.25e-06"/>
        </inertial>
        <collision>
            <origin xyz="0 0 0.02" rpy="0 0 0"/>
            <geometry>
                <cylinder radius="0.05" length="0.04"/>
            </geometry>
        </collision>
        <visual>
            <origin rpy="0.0 0 0" xyz="0 0 0"/>
            <geometry>
                <mesh filename="package://my_gurdy_description/models/gurdy/meshes/gurdy_head_v2.dae"/>
            </geometry>
        </visual>
    </link>

    <gazebo reference="head_link">
        <mu1>10.0</mu1>
        <mu2>10.0</mu2>
    </gazebo>

    <joint name="base_joint" type="fixed">
        <parent link="base_link"/>
        <child link="head_link"/>
        <origin xyz="0 0 0" rpy="0 -0 0"/>
    </joint>

</xacro:macro>

<xacro:macro name="upperleg_yaw_link" params="number">

    <link name="upperleg_M${number}_yaw_link">
        <inertial>
            <origin xyz="0 0 0" rpy="0 0 0"/>
            <mass value="0.01"/>
            <inertia ixx="2.13333e-07" ixy="0" ixz="0" iyy="2.13333e-07" iyz="0" izz="3.2e-07"/>            
        </inertial>
        <collision>
            <origin rpy="0.0 0 0" xyz="0 0 0"/>
            <geometry>
                <cylinder radius="0.008" length="0.008"/>
            </geometry>
        </collision>
        <visual>
            <origin rpy="0.0 0 0" xyz="0 0 0"/>
            <geometry>
                <cylinder radius="0.008" length="0.008"/>
            </geometry>
        </visual>
    </link>
    
</xacro:macro>

<xacro:macro name="trans_yaw" params="number">

    <transmission name="tran_M${number}_head_upper_yaw">

        <type>transmission_interface/SimpleTransmission</type>
        <joint name="head_upperlegM${number}_yaw_joint">
            <hardwareInterface>hardware_interface/EffortJointInterface</hardwareInterface>
        </joint>
        <actuator name="motor_M${number}_head_upper_yaw">
            <hardwareInterface>hardware_interface/EffortJointInterface</hardwareInterface>
            <mechanicalReduction>1</mechanicalReduction>
        </actuator>

    </transmission>

</xacro:macro>

<xacro:macro name="upperleg_link" params="number">

    <link name="upperleg_M${number}_link">

        <inertial>
            <origin xyz="0 0 0.03" rpy="0 0 0"/>
            <mass value="0.01"/>
            <inertia ixx="3.015625e-06" ixy="0" ixz="0" iyy="3.015625e-06" iyz="0" izz="3.125e-08"/>            
        </inertial>

        <collision>
            <origin rpy="0.0 0 0" xyz="0 0 0.03"/>
            <geometry>
                <cylinder length="0.06" radius="0.0025"/>
            </geometry>
        </collision>

        <visual>
            <origin rpy="0.0 0 0" xyz="0 0 0"/>
            <geometry>
                <mesh filename="package://my_gurdy_description/models/gurdy/meshes/gurdy_higherleg_v2.dae"/>
            </geometry>
        </visual>

    </link>

</xacro:macro>

<xacro:macro name="trans_upperleg" params="number">

    <transmission name="tran_M${number}_head_upper">

        <type>transmission_interface/SimpleTransmission</type>
        <joint name="head_upperlegM${number}_joint">
            <hardwareInterface>hardware_interface/EffortJointInterface</hardwareInterface>
        </joint>
        <actuator name="motor_M${number}_head_upper">
            <hardwareInterface>hardware_interface/EffortJointInterface</hardwareInterface>
            <mechanicalReduction>1</mechanicalReduction>
        </actuator>

    </transmission>

</xacro:macro>

<xacro:macro name="lowerleg_link" params="number">

    <link name="lowerleg_M${number}_link">

        <inertial>
            <origin xyz="0 0 0.03" rpy="0 0 0"/>
            <mass value="0.01"/>
            <inertia ixx="3.005625e-06" ixy="0" ixz="0" iyy="3.005625e-06" iyz="0" izz="1.125e-08"/>
        </inertial>

        <collision>
            <origin rpy="0 0 0" xyz="0 0 0.03"/>
            <geometry>
                <cylinder length="0.06" radius="0.0015"/>
            </geometry>
        </collision>

        <visual>
            <origin rpy="0 0 0" xyz="0 0 0"/>
            <geometry>
                <mesh filename="package://my_gurdy_description/models/gurdy/meshes/gurdy_lowerleg_v2.dae"/>
            </geometry>
        </visual>

    </link>

</xacro:macro>

<xacro:macro name="lowerleg_joint" params="number">

    <joint name="upperleg_lowerleg_M${number}_joint" type="revolute">

        <parent link="upperleg_M${number}_link"/>
        <child link="lowerleg_M${number}_link"/>
        <origin xyz="0 0.0095 0.06" rpy="0 0 3.14159"/>
        <limit lower="-2.9" upper="1.57" effort="1.0" velocity="0.005"/>
        <axis xyz="0 1 0"/>

    </joint>

    <transmission name="tran_M${number}_upper_lower">

        <type>transmission_interface/SimpleTransmission</type>
        <joint name="upperleg_lowerleg_M${number}_joint">
            <hardwareInterface>hardware_interface/EffortJointInterface</hardwareInterface>
        </joint>
        <actuator name="motor_M${number}_upper_lower">
            <hardwareInterface>hardware_interface/EffortJointInterface</hardwareInterface>
            <mechanicalReduction>1</mechanicalReduction>
        </actuator>

    </transmission>

</xacro:macro>

<xacro:macro name="foot_link" params="number color">

    <link name="foot_M${number}_link">

        <inertial>
            <origin xyz="0 0 0" rpy="0 0 0"/>
            <mass value="0.01"/>
            <inertia ixx="2.56e-07" ixy="0" ixz="0" iyy="2.56e-07" iyz="0" izz="2.56e-07"/>
        </inertial>

        <collision>
            <origin rpy="0 0 0" xyz="0 0 0"/>
            <geometry>
                <sphere radius="0.008"/>
            </geometry>
        </collision>

        <visual>
            <origin rpy="0 0 0" xyz="0 0 0"/>
            <geometry>
                <sphere radius="0.008"/>
            </geometry>
        </visual>

    </link>

    <gazebo reference="foot_M${number}_link">

        <kp>1000.0</kp>
        <kd>1000.0</kd>
        <mu1>10.0</mu1>
        <mu2>10.0</mu2>
        <material>Gazebo/${color}</material>

    </gazebo>

    <joint name="foot_lowerleg_M${number}_joint" type="fixed">

        <parent link="lowerleg_M${number}_link"/>
        <child link="foot_M${number}_link"/>
        <origin xyz="0 0 0.06" rpy="0 0 0"/>

    </joint>

</xacro:macro>

<xacro:macro name="gurdy_leg" params="head_link_name Number Color *origin1 *origin2">  
<!-- *upperleg_joint_origin -->

    <!-- apply yaw link -->
    <xacro:upperleg_yaw_link number="${Number}"/>

    <!-- define yaw joint -->
    <joint name="head_upperlegM${Number}_yaw_joint" type="revolute">
        <parent link="${head_link_name}"/>
        <child link="upperleg_M${Number}_yaw_link"/>
        <!-- origins of yaw joints are different, so here to individually define, as an insert_block -->
        <xacro:insert_block name="origin1"/>
        <limit lower="-0.7" upper="0.7" effort="1.0" velocity="0.005"/>
        <axis xyz="0 0 1"/>
    </joint>

    <!-- apply transmission of yaw joint -->
    <xacro:trans_yaw number="${Number}"/>

    <!-- apply upperleg link -->
    <xacro:upperleg_link number="${Number}"/>

    <!-- define upperleg joint -->
    <joint name="head_upperlegM${Number}_joint" type="revolute">
        <parent link="upperleg_M${Number}_yaw_link"/>
        <child link="upperleg_M${Number}_link"/>
        <xacro:insert_block name="origin2"/>
        <limit lower="-1.55" upper="0" effort="1.0" velocity="0.005"/>
        <axis xyz="0 1 0"/>
    </joint>

    <!-- apply transmission of upperleg joint -->
    <xacro:trans_upperleg number="${Number}"/>

    <!-- apply lowerleg link -->
    <xacro:lowerleg_link number="${Number}"/>

    <!-- apply lowerleg joint -->
    <xacro:lowerleg_joint number="${Number}"/>

    <!-- apply foot link -->
    <xacro:foot_link number="${Number}" color="${Color}"/>

</xacro:macro>

<xacro:macro name="control_system" params="namespace">

    <gazebo>
        <plugin name="gazebo_ros_control" filename="libgazebo_ros_control.so">
            <robotNamespace>/${namespace}</robotNamespace>
        </plugin>
    </gazebo>

    <gazebo>

        <plugin name="gazebo_ros_imu_controller" filename="libgazebo_ros_imu.so">
        <robotNamespace>/${namespace}</robotNamespace>
        <topicName>imu/data</topicName>
        <serviceName>imu/service</serviceName>
        <bodyName>base_link</bodyName>
        <gaussianNoise>0</gaussianNoise>
        <rpyOffsets>0 0 0</rpyOffsets>
        <updateRate>10.0</updateRate>
        <alwaysOn>true</alwaysOn>
        <gaussianNoise>0</gaussianNoise>
        </plugin>

    </gazebo>

</xacro:macro>

<xacro:gurdy_head />

<xacro:gurdy_leg head_link_name="head_link" Number="1" Color="Red">

    <origin1>
        <origin xyz="-0.02165 -0.0125 -0.008" rpy="0 0 0"/>
    </origin1>

    <origin2>
        <origin xyz="0 0 0" rpy="3.14159 0 0.523599"/>
    </origin2>

</xacro:gurdy_leg>

<!-- <xacro:gurdy_leg head_link_name="head_link" Number="2" Color="Green">
    <origin xyz="0.02165 -0.0125 -0.008" rpy="0 0 0"/>
    <uorigin xyz="0 0 0" rpy="3.14159 0 2.61799"/>
</xacro:gurdy_leg> -->

<!-- <xacro:gurdy_leg head_link_name="head_link" Number="3" Color="Blue">
    <origin xyz="0 0.025 -0.008" rpy="0 0 0"/> 
    <origin xyz="0 0 0" rpy="3.14159 0 -1.57"/>
</xacro:gurdy_leg> -->

<xacro:control_system namespace="gurdy"/>

(and it shoud contain this:
/robot>
but I don’t know why it cannot show when I sometimes add <>)

4

Hi,

Have a look at this example: Bitbucket

It doesn’t have the extra leg but it might give you some insight of the structure and use.