aaditya_saraiya's profile - activity

Hi,

While trying to move a robotic manipulator to a new pose (using MoveIt!), in order to move to the Next Best View of the manipulator's workspace using the YAK package, I repeatedly get this warning which states that

The weight on position constraint for link 'camera_depth_optical_frame' is near zero. Setting to 1.0.

Is this the reason why I am getting the following error?

Position constraint violated on link 'camera_depth_optical_frame'. Desired: -0.300000, -0.300000, 0.800000, current: -0.187025, 0.287808, 0.549807

[ WARN] [1530986530.323626313, 426.508000000]: Failed to fetch current robot state.
[ INFO] [1530986530.324177460, 426.508000000]: Combined planning and execution request received for MoveGroup action. Forwarding to planning and execution pipeline.
[ WARN] [1530986530.324308021, 426.508000000]: The weight on position constraint for link 'camera_depth_optical_frame' is near zero.  Setting to 1.0.
[ INFO] [1530986530.324483190, 426.508000000]: Planning attempt 1 of at most 1
[ WARN] [1530986530.325945894, 426.508000000]: The weight on position constraint for link 'camera_depth_optical_frame' is near zero.  Setting to 1.0.
[ INFO] [1530986530.326051436, 426.508000000]: Path constraints not satisfied for start state...
[ WARN] [1530986530.326549565, 426.508000000]: The weight on position constraint for link 'camera_depth_optical_frame' is near zero.  Setting to 1.0.
[ INFO] [1530986530.326762763, 426.508000000]: Position constraint violated on link 'camera_depth_optical_frame'. Desired: -0.300000, -0.300000, 0.800000, current: 0.816647, 0.204373, 0.491472
[ INFO] [1530986530.326923292, 426.508000000]: Differences -1.11665 -0.504373 0.308528
[ INFO] [1530986530.327083872, 426.508000000]: Planning to path constraints...
[ WARN] [1530986530.327393233, 426.508000000]: The weight on position constraint for link 'camera_depth_optical_frame' is near zero.  Setting to 1.0.
[ WARN] [1530986530.327645776, 426.508000000]: The weight on position constraint for link 'camera_depth_optical_frame' is near zero.  Setting to 1.0.
Debug:   Starting goal sampling thread
[ INFO] [1530986530.328125348, 426.508000000]: Planner configuration 'manipulator' will use planner 'geometric::RRTConnect'. Additional configuration parameters will be set when the planner is constructed.
Debug:   The value of parameter 'longest_valid_segment_fraction' is now: '0.0050000000000000001'
Debug:   RRTConnect: Planner range detected to be 7.539822
Info:    RRTConnect: Starting planning with 1 states already in datastructure
Debug:   RRTConnect: Waiting for goal region samples ...
Debug:   Beginning sampling thread computation
Debug:   RRTConnect: Waited 0.431969 seconds for the first goal sample.
Info:    RRTConnect: Created 4 states (2 start + 2 goal)
Info:    Solution found in 0.475992 seconds
Debug:   Attempting to stop goal sampling thread...
Debug:   Stopped goal sampling thread after 2 sampling attempts
Info:    SimpleSetup: Path simplification took 0.026644 seconds and changed from 3 to 2 states
[ INFO] [1530986530.925958530, 426.765000000]: Planned to path constraints. Resuming original planning request.
[ WARN] [1530986530.926477926, 426.765000000]: The weight on position constraint for link 'camera_depth_optical_frame' is near zero.  Setting to 1.0.
[ WARN] [1530986530.926728899, 426.765000000]: The weight on position constraint for link 'camera_depth_optical_frame' is near zero.  Setting to 1.0.
[ WARN] [1530986530.927186930, 426.765000000]: The weight on position constraint for link 'camera_depth_optical_frame' is near zero.  Setting to 1.0.
Debug:   Starting goal sampling thread
Debug:   Waiting for space information to be ...

Hey! I was trying to use a Kinect fusion package for my project on Robot Workcell Discovery. I am using ROS Kinetic and Ubuntu 16.04.

While launching the Kinect fusion node, I face the following error.

terminate called after throwing an instance of 'tf2::LookupException'. what(): Could not find a connection between 'volume_pose' and 'camera_depth_optical_frame' because they are not part of the same tree. Tf has two or more unconnected trees.

How as per the Link to the tf frames.pdf file generated created using rosrun tf view_frames these two frames seem to be in the same tree.

On some occasions, the same launch file gives the following error. terminate called after throwing an instance of 'tf2::LookupException' what(): "volume_pose" passed to lookupTransform argument target_frame does not exist.

This is the related code

if (!camera->nodeHandle.getParam("use_pose_hints", use_pose_hints_)) 
{
    ROS_INFO("Failed to get use_pose_hints flag!");
  }
 ROS_INFO_STREAM("Use pose hints set to " << use_pose_hints_);
 tfListener_.waitForTransform("volume_pose", "camera_depth_optical_frame", ros::Time::now(), ros::Duration(2));
tfListener_.lookupTransform("volume_pose", "camera_depth_optical_frame", ros::Time(0), previous_volume_to_sensor_transform_);
 }
    }

I have added Listener. waitForTransform() as mentioned in this answer. I have also added <param name="/use_sim_time" value="true"/> on the top of my launch files as as mentioned by some other answers, however the problem still persists.

There definitely seems to be a problem of the volume_pose not being available in time. What could be the potential reason and solution for this issue?

Edit: In one case, I received this error message as well which according to this link is again due to a delayed source of frames.

Warning: TF_OLD_DATA ignoring data from the past for frame table at time 0.165 according to authority unknown_publisher

Output of tf monitor

Waiting for transform chain to become available between volume_pose and camera_depth_optical_frame 

RESULTS: for volume_pose to camera_depth_optical_frame
 Chain is: volume_pose -> base_link -> table -> world -> shoulder_link -> upper_arm_link -> forearm_link -> wrist_1_link -> wrist_2_link -> wrist_3_link -> tool0 -> camera_link -> camera_depth_frame -> camera_depth_optical_frame
Net delay     avg = 0.00997896: max = 0.099

Frames:
Frame: base_link published by unknown_publisher(static) Average Delay: 0 Max Delay: 0
Frame: camera_depth_frame published by unknown_publisher(static) Average Delay: 0 Max Delay: 0
Frame: camera_depth_optical_frame published by unknown_publisher(static) Average Delay: 0 Max Delay: 0
Frame: camera_link published by unknown_publisher(static) Average Delay: 0 Max Delay: 0
Frame: forearm_link published by unknown_publisher Average Delay: 0.000272727 Max Delay: 0.003
Frame: shoulder_link published by unknown_publisher Average Delay: 0.000272727 Max Delay: 0.003
Frame: table published by unknown_publisher Average Delay: -0.0666667 Max Delay: 0
Frame: tool0 published by unknown_publisher(static) Average Delay: 0 Max Delay: 0
Frame: upper_arm_link published by unknown_publisher Average Delay: 0.000272727 Max Delay: 0.003
Frame: volume_pose published by unknown_publisher Average Delay: 0 Max Delay: 0
Frame: wrist_1_link published by unknown_publisher Average Delay: 0.000272727 Max Delay: 0.003
Frame: wrist_2_link published by unknown_publisher Average Delay: 0.000272727 Max Delay: 0.003
Frame: wrist_3_link published by unknown_publisher Average Delay: 0.000272727 Max Delay: 0.003

All Broadcasters:
Node: unknown_publisher 85 Hz, Average Delay: -0.0233529 Max Delay: 0.003
Node: unknown_publisher ...

Hey!

For my GSoC 2018 project, I had previously attached a Kinect sensor to the UR5 robot, generated MoveIt! Config packages for them and tested it on RViz. I was able to spawn the robot with the controllers activated in Gazebo. The next step of my project was to be able to command the robot in Gazebo using MoveIt!.

In this process of trying to launch the robot in Gazebo, I noticed that the arm_controller/joint_trajectory topics which are related to the action server are not being displayed while using rostopic list. However, the weird part is that on launch, the initial information from the terminal shows that the arm_controller_spawner node has started. This link had a related solution but it didn't work.

I previously downloaded the Universal robot Github package and the ur5.launch file loads the required arm_controller.joint_trajectory topics properly. However, that same thing was not working with my files (which are minor edits of the UR5 files). I am not able to figure out why exactly is this happening. I have attached the related files with this question. Thanks in advance. Edit: While comparing with the UR5 launch, I realised that the arm_controller and joint_state_controller are not loaded successfully with my model as that message is not showing on the terminal with Gazebo launch.

The complete URDF file can be accessed via this Google Drive Link.

Gazebo Robot Launch file

<?xml version="1.0"?>

<!-- Gazebo Launch file -->
<launch>
  <arg name="limited" default="false"/>
  <arg name="paused" default="false"/>
  <arg name="gui" default="true"/>

  <!-- startup simulated world -->
  <include file="$(find gazebo_ros)/launch/empty_world.launch">
    <arg name="world_name" default="worlds/empty.world"/>
    <arg name="paused" value="$(arg paused)"/>
    <arg name="gui" value="$(arg gui)"/>
    <arg name="verbose" value="true" />
  </include>

  <!-- send robot urdf to param server -->
  <include file="$(find myworkcell_support)/launch/workcell_ur5.launch">
  <!-- <arg name="limited" value="$(arg limited)"/> -->
  </include>

  <!-- push robot_description to factory and spawn robot in gazebo -->
  <node name="spawn_gazebo_model" pkg="gazebo_ros" type="spawn_model" args="-urdf -param robot_description -model robot -z 0.1" respawn="false" output="screen" />

  <!-- push robot_description to factory and spawn robot in gazebo -->
  <include file="$(find myworkcell_support)/gazebo/launch/controller_utils.launch"/>

  <rosparam file="$(find myworkcell_support)/gazebo/controller/myworkcell_control.yaml" command="load"/>
  <node name="arm_controller_spawner" pkg="controller_manager" type="controller_manager" args="spawn arm_controller" respawn="false" output="screen"/>

</launch>

workcell_ur5.launch file

<launch>
  <arg name="gui" default="true"/>
  <param name="robot_description" command="$(find xacro)/xacro --inorder '$(find myworkcell_support)/urdf/workcell_gazebo_trial1.urdf'" /> 
  <param name="use_gui" value="$(arg gui)"/>
</launch>

controller_utils.launch

<?xml version="1.0"?>
<launch>

  <!-- Robot state publisher -->
  <node pkg="robot_state_publisher" type="robot_state_publisher" name="robot_state_publisher">
    <param name="publish_frequency" type="double" value="50.0" />
    <param name="tf_prefix" type="string" value="" />
  </node>

  <!-- Fake Calibration -->
  <node pkg="rostopic" type="rostopic" name="fake_joint_calibration"
        args="pub /calibrated std_msgs/Bool true" />

  <!-- joint_state_controller -->
  <rosparam file="$(find myworkcell_support)/gazebo/controller/joint_state_controller.yaml" command="load"/>
  <node name="joint_state_controller_spawner" pkg="controller_manager" type="controller_manager" args="spawn joint_state_controller" respawn="false" output="screen"/>

</launch>

myworkcell_control.yaml

arm_controller:
  type: position_controllers/JointTrajectoryController
  joints:
     - shoulder_pan_joint
     - shoulder_lift_joint
     - elbow_joint
     - wrist_1_joint
     - wrist_2_joint
     - wrist_3_joint
  constraints ...