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Problem with propellers rotating around middle of robot.

I am making a quadcopter and the propellers are rotating around the center of the robot. I am trying to get the propellers to be stationary and just rotate in place. I have added some pictures of before and during rotation to show the problem. Below is the code I am using. Any help would be appreciated.

image description

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<?xml version="1.0"?>


<material name="magenta">
    <color rgba="1 .1 .85 1"/>
</material>

<link name="dummy">


<link name="base_link">
    <inertial>
        <origin xyz="0 0 0" rpy="0 0 0"/>
        <mass value="1" />
        <inertia ixx="0.0" ixy="0.0" ixz="0.0" iyy="0.0" iyz="0.0" izz="0.0"/>
    </inertial>
    <collision>
        <origin xyz="0 0 0" rpy="0 0 0"/>
        <geometry>
            <box size="0.5 0.5 0.5"/>
        </geometry>
    </collision>
    <visual>
        <origin rpy="0.0 0 0" xyz="0 0 0"/>
        <geometry>
            <box size="0.2 0.2 0.1"/>
        </geometry>
        <material name="magenta"/>
    </visual>
</link>

<link name="propeller_M1_link">
    <inertial>
        <origin rpy="0.0 0 0" xyz="0.25 0 0.0422"/>
        <mass value="0.1" />
        <inertia ixx="0.0" ixy="0.0" ixz="0.0" iyy="0.0" iyz="0.0" izz="0.0"/>
    </inertial>
    <collision>
        <origin rpy="0.0 0 0" xyz="0.25 0 0.0422"/>
        <geometry>
            <cylinder radius="0.06" length="0.0324"/>
        </geometry>
        <material name="magenta"/>
    </collision>
    <visual>
        <origin rpy="0.0 0 0" xyz="0.25 0 0.0422"/>
        <geometry>
            <cylinder radius="0.06" length="0.0324"/>
        </geometry>
        <material name="magenta"/>
    </visual>
</link>

<link name="arm_M1_link">
    <inertial>
        <origin xyz="0 0 0" rpy="0 0 0"/>
        <mass value="0.18" />
        <inertia ixx="0.0" ixy="0.0" ixz="0.0" iyy="0.0" iyz="0.0" izz="0.0"/>
    </inertial>
    <collision>
        <origin rpy="0 0 0" xyz="0.175 0 0"/>
        <geometry>
            <box size="0.15 0.05 0.05"/>
        </geometry>
        <material name="magenta"/>
    </collision>
    <visual>
        <origin rpy="0 0 0" xyz="0.175 0 0"/>
        <geometry>
            <box size="0.15 0.05 0.05"/>
        </geometry>
        <material name="magenta"/>
    </visual>
</link>
 <link name="motor_M1_link">
    <inertial>
        <origin rpy="0.0 0 0" xyz="0.25 0 0.0255"/>
        <mass value="0.1" />
        <inertia ixx="0.0" ixy="0.0" ixz="0.0" iyy="0.0" iyz="0.0" izz="0.0"/>
    </inertial>
    <collision>
        <origin rpy="0.0 0 0" xyz="0.25 0 0.0255"/>
        <geometry>
            <cylinder radius="0.006" length="0.001"/>
        </geometry>
        <material name="magenta"/>
    </collision>
    <visual>
        <origin rpy="0.0 0 0" xyz="0.25 0 0.0255"/>
        <geometry>
            <cylinder radius="0.006" length="0.001"/>
        </geometry>
        <material name="magenta"/>
    </visual>
</link>
<link name="propeller_M2_link">
    <inertial>
        <origin rpy="0 0 0" xyz="-0.25 0 0.0422"/>
        <inertia ixx="0.0" ixy="0.0" ixz="0.0" iyy="0.0" iyz="0.0" izz="0.0"/>
        <mass value="0.1"/>
    </inertial>
    <collision>
        <origin rpy="0 0 0" xyz="-0.25 0 0.0422"/>
        <geometry>
            <cylinder radius="0.06" length="0.0324"/>
        </geometry>
        <material name="magenta"/>
    </collision>
    <visual>
        <origin rpy="0 0 0" xyz="-0.25 0 0.0422"/>
        <geometry>
            <cylinder radius="0.06" length="0.0324"/>
        </geometry>
        <material name="magenta"/>
    </visual>
</link>

<link name="arm_M2_link">
    <inertial>
        <origin xyz="0 0 0" rpy="0 0 0"/>
        <mass value="0.18" />
        <inertia ixx="0.0" ixy="0.0" ixz="0.0" iyy="0.0" iyz="0.0" izz="0.0"/>
    </inertial>
    <collision>
        <origin rpy="0 0 0" xyz="-0.175 0 0"/>
        <geometry>
            <box size="0.15 0.05 0.05"/>
        </geometry>
        <material name="magenta"/>
    </collision>
    <visual>
        <origin rpy="0 0 0" xyz="-0.175 0 0"/>
        <geometry>
            <box size="0.15 0.05 0.05"/>
        </geometry>
        <material name="magenta"/>
    </visual>
</link>
<link name="motor_M2_link">
    <inertial>
        <origin rpy="0.0 0 0" xyz="-0.25 0 0.0255"/>
        <mass value="0.1" />
        <inertia ixx="0.0" ixy="0.0" ixz="0.0" iyy="0.0" iyz="0.0" izz="0.0"/>
    </inertial>
    <collision>
        <origin rpy="0.0 0 0" xyz="-0.25 0 0.0255"/>
        <geometry>
            <cylinder radius="0.006" length="0.001"/>
        </geometry>
        <material name="magenta"/>
    </collision>
    <visual>
        <origin rpy="0.0 0 0" xyz="-0.25 0 0.0255"/>
        <geometry>
            <cylinder radius="0.006" length="0.001"/>
        </geometry>
        <material name="magenta"/>
    </visual>
</link>

<link name="propeller_M3_link">
   <inertial>
        <origin rpy="0 0 0" xyz="0 0.25 0.0422"/>
        <inertia ixx="0.0" ixy="0.0" ixz="0.0" iyy="0.0" iyz="0.0" izz="0.0"/>
        <mass value="0.1"/>
    </inertial>
    <collision>
        <origin rpy="0 0 0" xyz="0 0.25 0.0422"/>
        <geometry>
            <cylinder radius="0.06" length="0.0324"/>
        </geometry>
        <material name="magenta"/>
    </collision>
    <visual>
        <origin rpy="0 0 0" xyz="0 0.25 0.0422"/>
        <geometry>
            <cylinder radius="0.06" length="0.0324"/>
        </geometry>
        <material name="magenta"/>
    </visual>

</link>

<link name="arm_M3_link">
    <inertial>
        <origin xyz="0 0 0" rpy="0 0 0"/>
        <mass value="0.18" />
        <inertia ixx="0.0" ixy="0.0" ixz="0.0" iyy="0.0" iyz="0.0" izz="0.0"/>
    </inertial>
    <collision>
        <origin rpy="0 0 0" xyz="0 0.175 0"/>
        <geometry>
            <box size="0.05 0.15 0.05"/>
        </geometry>
        <material name="magenta"/>
    </collision>
    <visual>
        <origin rpy="0 0 0" xyz="0 0.175 0"/>
        <geometry>
            <box size="0.05 0.15 0.05"/>
        </geometry>
        <material name="magenta"/>
    </visual>
</link>
<link name="motor_M3_link">
    <inertial>
        <origin rpy="0 0 0" xyz="0 0.25 0.0255"/>
        <mass value="0.1" />
        <inertia ixx="0.0" ixy="0.0" ixz="0.0" iyy="0.0" iyz="0.0" izz="0.0"/>
    </inertial>
    <collision>
        <origin rpy="0 0 0" xyz="0 0.25 0.0255"/>
        <geometry>
            <cylinder radius="0.006" length="0.001"/>
        </geometry>
        <material name="magenta"/>
    </collision>
    <visual>
        <origin rpy="0 0 0" xyz="0 0.25 0.0255"/>
        <geometry>
            <cylinder radius="0.006" length="0.001"/>
        </geometry>
        <material name="magenta"/>
    </visual>
</link>

<link name="propeller_M4_link">
    <inertial>
        <origin rpy="0 0 0" xyz="0 -0.25 0.0422"/>
        <inertia ixx="0.0" ixy="0.0" ixz="0.0" iyy="0.0" iyz="0.0" izz="0.0"/>
        <mass value="0.1"/>
    </inertial>
    <collision>
        <origin rpy="0 0 0" xyz="0 -0.25 0.0422"/>
        <geometry>
            <cylinder radius="0.06" length="0.0324"/>
        </geometry>
        <material name="magenta"/>
    </collision>
    <visual>
        <origin rpy="0 0 0" xyz="0 -0.25 0.0422"/>
        <geometry>
            <cylinder radius="0.06" length="0.0324"/>
        </geometry>
        <material name="magenta"/>
    </visual>
</link>

<link name="arm_M4_link">
    <inertial>
        <origin xyz="0 0 0" rpy="0 0 0"/>
        <mass value="0.18" />
        <inertia ixx="0.0" ixy="0.0" ixz="0.0" iyy="0.0" iyz="0.0" izz="0.0"/>
    </inertial>
    <collision>
        <origin rpy="0 0 0" xyz="0 -0.175 0"/>
        <geometry>
            <box size="0.05 0.15 0.05"/>
        </geometry>
        <material name="magenta"/>
    </collision>
    <visual>
        <origin rpy="0 0 0" xyz="0 -0.175 0"/>
        <geometry>
            <box size="0.05 0.15 0.05"/>
        </geometry>
        <material name="magenta"/>
    </visual>
</link>
<link name="motor_M4_link">
    <inertial>
        <origin rpy="0 0 0" xyz="0 -0.25 0.0255"/>
        <mass value="0.1" />
        <inertia ixx="0.0" ixy="0.0" ixz="0.0" iyy="0.0" iyz="0.0" izz="0.0"/>
    </inertial>
    <collision>
        <origin rpy="0 0 0" xyz="0 -0.25 0.0255"/>
        <geometry>
            <cylinder radius="0.006" length="0.001"/>
        </geometry>
        <material name="magenta"/>
    </collision>
    <visual>
        <origin rpy="0 0 0" xyz="0 -0.25 0.0255"/>
        <geometry>
            <cylinder radius="0.006" length="0.001"/>
        </geometry>
        <material name="magenta"/>
    </visual>
</link>

<joint name="arm_base_M1_joint" type="fixed">
    <parent link="base_link"/>
    <child link="arm_M1_link"/>
    <!-- <origin xyz="0.125 0 0" rpy="0 0 0"/> -->
</joint>
<joint name="arm_base_M2_joint" type="fixed">
    <parent link="base_link"/>
    <child link="arm_M2_link"/>
    <!-- <origin xyz="-0.125 0 0" rpy="0 0 0"/> -->
</joint>
<joint name="arm_base_M3_joint" type="fixed">
    <parent link="base_link"/>
    <child link="arm_M3_link"/>
    <!-- <origin xyz="0 0.125 0" rpy="0 0 0"/> -->
</joint>
<joint name="arm_base_M4_joint" type="fixed">
    <parent link="base_link"/>
    <child link="arm_M4_link"/>
    <!-- <origin xyz="0 -0.125 0" rpy="0 0 0"/> -->
</joint>
<joint name="motor_arm_M1_joint" type="revolute">
    <parent link="arm_M1_link"/>
    <child link="motor_M1_link"/>
    <limit effort="0" lower="-0.0" upper="0.0" velocity="0"/>
    <!-- <origin xyz="0 -0.125 0" rpy="0 0 0"/> -->
</joint>
<joint name="motor_arm_M2_joint" type="revolute">
    <parent link="arm_M2_link"/>
    <child link="motor_M2_link"/>
    <limit effort="0" lower="-0.0" upper="0.0" velocity="0"/>
    <!-- <origin xyz="0 -0.125 0" rpy="0 0 0"/> -->
</joint>
<joint name="motor_arm_M3_joint" type="revolute">
    <parent link="arm_M3_link"/>
    <child link="motor_M3_link"/>
    <limit effort="0" lower="-0.0" upper="0.0" velocity="0"/>
    <!-- <origin xyz="0 -0.125 0" rpy="0 0 0"/> -->
</joint>
<joint name="motor_arm_M4_joint" type="revolute">
    <parent link="arm_M4_link"/>
    <child link="motor_M4_link"/>
    <limit effort="0" lower="-0.0" upper="0.0" velocity="0"/>
    <!-- <origin xyz="0 -0.125 0" rpy="0 0 0"/> -->
</joint>

<gazebo>
    <plugin name="gazebo_ros_control" filename="libgazebo_ros_control.so">
        <robotNamespace>/drone</robotNamespace>
    </plugin>
</gazebo>

<!-- --> <!-- --> <!-- --> <!-- --> 

<transmission name="tran1">
    <type>transmission_interface/SimpleTransmission</type>
    <joint name="propeller_arm_M1_joint">
        <hardwareInterface>EffortJointInterface</hardwareInterface>
    </joint>
    <actuator name="motor1">
        <hardwareInterface>EffortJointInterface</hardwareInterface>
        <mechanicalReduction>1</mechanicalReduction>
    </actuator>
</transmission>

<transmission name="tran2">
    <type>transmission_interface/SimpleTransmission</type>
    <joint name="propeller_arm_M2_joint">
        <hardwareInterface>EffortJointInterface</hardwareInterface>
    </joint>
    <actuator name="motor2">
        <hardwareInterface>EffortJointInterface</hardwareInterface>
        <mechanicalReduction>1</mechanicalReduction>
    </actuator>
</transmission>

<transmission name="tran3">
    <type>transmission_interface/SimpleTransmission</type>
    <joint name="propeller_arm_M3_joint">
        <hardwareInterface>EffortJointInterface</hardwareInterface>
    </joint>
    <actuator name="motor3">
        <hardwareInterface>EffortJointInterface</hardwareInterface>
        <mechanicalReduction>1</mechanicalReduction>
    </actuator>
</transmission>

<transmission name="tran4">
    <type>transmission_interface/SimpleTransmission</type>
    <joint name="propeller_arm_M4_joint">
        <hardwareInterface>EffortJointInterface</hardwareInterface>
    </joint>
    <actuator name="motor4">
        <hardwareInterface>EffortJointInterface</hardwareInterface>
        <mechanicalReduction>1</mechanicalReduction>
    </actuator>
</transmission>


<!-- <gazebo reference="base_link">
    <material>Gazebo/Blue</material>
</gazebo>
<gazebo reference="propeller_M1_link">
    <material>Gazebo/Blue</material>
</gazebo>
<gazebo reference="propeller_M2_link">
    <material>Gazebo/Blue</material>
</gazebo>
<gazebo reference="propeller_M3_link">
    <material>Gazebo/Blue</material>
</gazebo>
<gazebo reference="propeller_M4_link">
    <material>Gazebo/Blue</material>
</gazebo>
<gazebo reference="arm_M1_link">
    <material>Gazebo/Blue</material>
</gazebo>
<gazebo reference="arm_M2_link">
    <material>Gazebo/Blue</material>
</gazebo>
<gazebo reference="arm_M3_link">
    <material>Gazebo/Blue</material>
</gazebo>
<gazebo reference="arm_M4_link">
    <material>Gazebo/Blue</material>
</gazebo> -->

Asked by Resilient System Laboratory on 2020-01-15 12:52:22 UTC

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