Rick C NIST's profile - activity

Hi Benjamin, Yes, I was using the plugin that you mentioned.

Joints at all 0 means the home position (i.e. all scrunched up) Here is a picture of the home position: http://www.kuka-labs.com/NR/rdonlyres/17026737-5839-4346-9939-5D012133E9FE/0/service_youBot_Features.jpg. I would have thought that get_random_pose() would give me a valid pose.

I am using the Kuka youbot URDF unmodified which I am assuming is correct. The setup assistant could be the problem or maybe that I am not setting the end effector link? One interesting data point is that if I call group.set_pose_target(pose) and then group.plan(), I get a valid trajectory from Moveit.

Hello, I am using ROS Hydro on Ubuntu 12.04. When calling MoveIt! Commander's (Python) move_group.compute_cartesian_path() method, the return value is always the current joint configuration. The code looks something like this.

eef_link = "gripper_palm_link"
waypoints = []
waypoints = group.get_random_pose(eef_link)
poses.append(copy.deepcopy(pose.pose))
waypoints = group.get_random_pose(eef_link)
poses.append(copy.deepcopy(pose.pose))
(plan, fraction) = group.compute_cartesian_path(waypoints, eef_step=0.01, jump_threshold=0.0, avoid_collisions=True)

My robot starts off in the home position which is essentially joint positions set to all zeros. After the call to compute_cartesian_path() the resultant joint trajectory look like this:

header: 
  seq: 20
  stamp: 
    secs: 0
    nsecs: 0
  frame_id: base_link
joint_names: ['arm_joint_1', 'arm_joint_2', 'arm_joint_3', 'arm_joint_4', 'arm_joint_5']
points: 
  - 
    positions: [0.001216606411158061, 0.0001137616260065144, -0.0006536926007463251, 0.0025598054398985326, 0.0007543179427678126]
    velocities: [0.0, 0.0, 0.0, 0.0, 0.0]
    accelerations: [0.0, 0.0, 0.0, 0.0, 0.0]
    effort: []
    time_from_start: 
      secs: 2
      nsecs: 0

The positions are essentially zero (i.e., the home position). I suspect that the call to group.get_random_pose(eef_link) is returning an invalid end effector position, but I don't know why it would do that. Any help would be appreciated.

Thank you. That was what I was looking for. I will use the rospy.Duration method from now on.

Thank you. That was what I was looking for. I will use the rospy.Duration method from now on.

Ubuntu 12.04 ROS Hydro

I am publishing a JointTrajectory to Gazebo and monitoring the topic using rostopic echo. The data that I publish is different from what gets captured by rostopic echo. Somehow the "time_from_start" portion of the data gets zeroed out.

A snippet of my code is as follows

  # this is where I create and populate the JointTrajectory
  jt = make_trajectory_msg(plan=plan, secs=0.5, dt=0.2, frame_id='base_link' )
  rospy.loginfo("Publishing joint trajectory")
  while not rospy.is_shutdown():
    print jt
    gazebo_command_publisher.publish(jt)
    r.sleep()

As you can see, right before I call publish() I print the trajectory. Here is what the trajectory looks like before the publish()

header: 
  seq: 5
  stamp: 
    secs: 0
    nsecs: 0
  frame_id: base_link
joint_names: ['arm_joint_1', 'arm_joint_2', 'arm_joint_3', 'arm_joint_4', 'arm_joint_5']
points: 
  - 
    positions: [0.2792831707677692, 0.4627657000396006, -0.8622084888670658, 0.8533643604717218, 0.1568816032950613]
    velocities: [0.0, 0.0, 0.0, 0.0, 0.0]
    accelerations: [0.0, 0.0, 0.0, 0.0, 0.0]
    effort: []
    time_from_start: 
      secs: 0.7
      nsecs: 0

And here is the trajectory after it is captured by rostopic echo:

header: 
  seq: 5
  stamp: 
    secs: 0
    nsecs: 0
  frame_id: base_link
joint_names: ['arm_joint_1', 'arm_joint_2', 'arm_joint_3', 'arm_joint_4', 'arm_joint_5']
points: 
  - 
    positions: [0.2792831707677692, 0.4627657000396006, -0.8622084888670658, 0.8533643604717218, 0.1568816032950613]
    velocities: [0.0, 0.0, 0.0, 0.0, 0.0]
    accelerations: [0.0, 0.0, 0.0, 0.0, 0.0]
    effort: []
    time_from_start: 
      secs: 0
      nsecs: 0

I reran the moveit setup assistant, and this problem went away. Must have been an error in one of my configuration files

I reran the moveit setup assistant, and this problem went away. Must have been an error in one of my configuration files

OS: Ubuntu 12.04 ROS and ROS packages installed with apt-get

My code

#!/usr/bin/python

import sys
import copy
import rospy
import moveit_commander
import moveit_msgs.msg
import geometry_msgs.msg

print("============ Starting tutorial setup")
moveit_commander.roscpp_initialize(sys.argv)
rospy.init_node('my_youbot_moveit', anonymous=True)
robot = moveit_commander.RobotCommander()

My output

[rick@rick-hydro:~/catkin_ws] rosrun moveit_my_youbot moveit_my_youbot.py
============ Starting tutorial setup
Segmentation fault (core dumped)

Checking dependencies

[rick@rick-hydro:/opt/ros/hydro/share] rosdep check moveit_commander
All system dependencies have been satisified

Please, any ideas why the python script is faulting and how to correct it? Thanks.

I think that I resolved the problem just by rebooting. I closed all terminals. Logged out and logged back in. The problem disappeared.

Hello ROS Community,

This is my first post to this forum. I am attempting to run the tutorial for moveit using python. Specifically the Move Group Interface/Python API tutorial. Sorry, my karma is not yet good enough to post links.

• I am running python 2.7.
• OS is Ubuntu 12.04
• ROS and ROS packages are installed using apt-get

I have created a package called my_youbot_moveit with a simple python script. The script contains the following:

import sys
import copy
import rospy
import moveit_commander
import moveit_msgs.msg
import geometry_msgs.msg

print("============ Starting tutorial setup")
moveit_commander.roscpp_initialize(sys.argv)
rospy.init_node('move_group_python_interface_tutorial', anonymous=True)

When I run the code

source ~/catkin/develop/setup.bash
rosrun my_youbot_moveit my_youbot_moveit.py

I get the error

Exception in thread Thread-3:
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 551, in __bootstrap_inner
    self.run()
  File "/usr/lib/python2.7/threading.py", line 504, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/opt/ros/hydro/lib/python2.7/dist-packages/rospy/impl/tcpros_base.py", line 153, in run
    (client_sock, client_addr) = self.server_sock.accept()
  File "/usr/lib/python2.7/socket.py", line 202, in accept
    sock, addr = self._sock.accept()
  File "/usr/lib/python2.7/socket.py", line 170, in _dummy
    raise error(EBADF, 'Bad file descriptor')
error: [Errno 9] Bad file descriptor

Please help me understand what is causing this problem and how to solve it.

Hello ROS Community,

This is my first post to this forum. I am attempting to run the tutorial for moveit using python. Specifically the Move Group Interface/Python API tutorial. Sorry, my karma is not yet good enough to post links.

• I am running python 2.7.
• OS is Ubuntu 12.04
• ROS and ROS packages are installed using apt-get

I have created a package called my_youbot_moveit with a simple python script. The script contains the following:

import sys
import copy
import rospy
import moveit_commander
import moveit_msgs.msg
import geometry_msgs.msg

print("============ Starting tutorial setup")
moveit_commander.roscpp_initialize(sys.argv)
rospy.init_node('move_group_python_interface_tutorial', anonymous=True)

When I run the code

source ~/catkin/develop/setup.bash
rosrun my_youbot_moveit my_youbot_moveit.py

I get the error

Exception in thread Thread-3:
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 551, in __bootstrap_inner
    self.run()
  File "/usr/lib/python2.7/threading.py", line 504, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/opt/ros/hydro/lib/python2.7/dist-packages/rospy/impl/tcpros_base.py", line 153, in run
    (client_sock, client_addr) = self.server_sock.accept()
  File "/usr/lib/python2.7/socket.py", line 202, in accept
    sock, addr = self._sock.accept()
  File "/usr/lib/python2.7/socket.py", line 170, in _dummy
    raise error(EBADF, 'Bad file descriptor')
error: [Errno 9] Bad file descriptor

Please help me understand what is causing this problem and how to solve it.