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My robot has an IMU attached to its arm. The following URDF xacro macro is defining the IMU:

<xacro:macro name="xsens_imu" params="prefix parent xyz rpy simulation:=false">

    <material name="xsens-orange">
        <color rgba="0.8862745098 0.56862745098 0.09019607843 1"/>
    </material>

    <joint name="${parent}_to_xsens_imu" type="fixed">
        <parent link="${parent}"/>
        <child link="xsens_imu"/>
        <origin xyz="${xyz}" rpy="${rpy}"/>
    </joint>

    <link name="xsens_imu">
        <visual>
            <origin rpy="0 0 0" xyz="0 0 0"/>
            <geometry>
                <box size="0.057 0.041 0.024"/> <!--a simple box is used with the outer dimensions for simplicity-->
            </geometry>
            <material name="xsens-orange"/>
        </visual>
        <collision>
            <origin rpy="0 0 0" xyz="0 0 0"/>
            <geometry>
                <box size="0.057 0.041 0.024"/>
            </geometry>
        </collision>
        <inertial>
            <mass value="0.055"/>
            <origin xyz="0 0 0"/>
            <inertia ixx="1.60333333333e-05" ixy="0.0" ixz="0.0" iyy="2.80333333333e-05" iyz="0.0"
                     izz="1.60333333333e-05"/>
        </inertial>
    </link>

    <xacro:if value="${simulation}">
        <gazebo>
            <plugin name="imu_controller" filename="libhector_gazebo_ros_imu.so">
                <alwaysOn>true</alwaysOn>
                <updateRate>400.0</updateRate>
                <bodyName>xsens_imu</bodyName>
                <topicName>imu</topicName>
                <robotNamespace>sensors</robotNamespace>
                <serviceName>imu/is_calibrated</serviceName>
                <gaussianNoise>0.00000001</gaussianNoise>
                <xyzOffsets>0 0 0</xyzOffsets>
                <rpyOffsets>0 0 0</rpyOffsets>
                <frameId>world</frameId>
            </plugin>
        </gazebo>
    </xacro:if>
</xacro:macro>

But when I attach it to my robot, the outputs of the IMU are wrong. The resulting direction of the linear acceleration does not make sense to me. As the robot is stationary in this moment, I expect the acceleration to be in z direction -9.81 and zero otherwise.

header: 
  seq: 150358
  stamp: 
    secs: 376
    nsecs: 345000000
  frame_id: "kinova_link_6"
orientation: 
  x: -0.707163260091
  y: 0.492549225252
  z: 0.00974669647696
  w: -0.507168991746
orientation_covariance: [1.0391111027982223e-18, 0.0, 0.0, 0.0, 1.0391111027982223e-18, 0.0, 0.0, 0.0, 0.0]
angular_velocity: 
  x: 2.01395400932e-08
  y: -1.39027463744e-08
  z: -1.25824759946e-09
angular_velocity_covariance: [1.0000000000000001e-16, 0.0, 0.0, 0.0, 1.0000000000000001e-16, 0.0, 0.0, 0.0, 1.0000000000000001e-16]
linear_acceleration: 
  x: 4.7659779885
  y: 7.13092593212
  z: -4.76145551598
linear_acceleration_covariance: [1.0000000000000001e-16, 0.0, 0.0, 0.0, 1.0000000000000001e-16, 0.0, 0.0, 0.0, 1.0000000000000001e-16]

One thing that makes me think is the frame of the IMU measurement. I want to have it in world coordinates, not in the kinova_link_6 (which is just the last link of the robot).

Does anyone see a mistake in my URDF that could fix this problem?

Thanks a lot!

edit: I added <frameId>world</frameId> but still do not get the desired result.

So I solved it by myself. Even though it's kind of a hack. The problem actually did not occur in the shown URDF above bu

IMU plugin has strange measurements in RViz My robot has an IMU attached to its arm. The following URDF xacro macro is

IMU plugin has strange measurements in RViz My robot has an IMU attached to its arm. The following URDF xacro macro is

IMU plugin has strange measurements in RViz My robot has an IMU attached to its arm. The following URDF xacro macro is

IMU plugin has strange measurements in RViz My robot has an IMU attached to its arm. The following URDF xacro macro is

IMU plugin has strange measurements in RViz My robot has an IMU attached to its arm. The following URDF xacro macro is

IMU plugin has strange measurements in RViz My robot has an IMU attached to its arm. The following URDF xacro macro is

IMU plugin has strange measurements in RViz My robot has an IMU attached to its arm. The following URDF xacro macro is

Thanks. I really found a bug in my code now that fixed the problem. I gave up after multiple days of debugging but took

Hi guys

I am writing a controller for a 6DOF robot arm. I am generating paths for the robot to come from the starting point to a desired pose. To do this I do a piecewise polynomial interpolation. Meaning that I first easily interpolate linearly over time between the two points. And then I attach a 6-degree polynomial in the beginning and the end to smoothen the motion. It looks then as follows:

Now I have the problem, that because of numerical issues (at least I think so) or because of time discretization, I got small jumps between the different polynoms:

My idea is now to just filter the paths to get rid of these jumps. For this I need to store the path somehow that I can filter it but I don't really have an idea what is a good way of doing this. How are paths saved for example in MoveIt? Do they save discrete or continuous paths? Is there a way of connecting my polynoms to make it "filterable"?

Thanks for your help!

Yes of course. When I posted the question this morning I did not have enough karma yet. Updated my question accordingly.

Yes of course. When I posted the question this morning I did not have enough karma yet.

What is a good way of storing robot paths and access them? Hi guys I am writing a controller for a 6DOF robot arm. I am

Hi, yes of course. When I posted the question this morning I did not have enough karma yet.

I actually never tried this. I still like to have the terminal open to launch my nodes. I found the option "create comma

I also use CLion and had a hard time to start with it. But it works perfect like this: Source your workspace Start CL

What is a good way of storing robot paths and access them? Hi guys I am writing a controller for a 6DOF robot arm. I am

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