lr101095

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About lr101095

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    University of Technology, Sydney

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  1. lr101095

    gazebo simulation not running

    Hi Shiwei, Thanks for your response. I am indeed running Ubuntu 16.04 and ROS Kinetic. I meet all the minimum requirements, except for the Nvidia requirement. Although i do have a dedicated Radeon graphics card, Ubuntu does not recognise it when i look at the graphics status. I already looked at the suggested post before i posted my own topic and i didn't find anything that was of help. An issue though is that I have been using the simulation for several months now, and this issue suddenly came up. I know this happened after i tried to remove some ROS packages. although, i re-ran through the workstation setup for the simulation fully. but this is still an issue. Are there any other suggestions i may be able to try? Again, many thanks for your help! regards, Luke
  2. lr101095

    gazebo simulation not running

    [base_to_world-3] process has died [pid 24561, exit code -11, cmd /opt/ros/kinetic/lib/tf2_ros/static_transform_publisher 0 0 0 0 0 0 1 world base __name:=base_to_world __log:=/home/lr101095/.ros/log/18c879c0-b4aa-11e8-9b83-f894c21f9c3f/base_to_world-3.log]. log file: /home/lr101095/.ros/log/18c879c0-b4aa-11e8-9b83-f894c21f9c3f/base_to_world-3*.log [ INFO] [1536553774.216652389]: Finished loading Gazebo ROS API Plugin. [ INFO] [1536553774.217655274]: waitForService: Service [/gazebo/set_physics_properties] has not been advertised, waiting... [ INFO] [1536553774.267867574]: Finished loading Gazebo ROS API Plugin. [ INFO] [1536553774.268545185]: waitForService: Service [/gazebo/set_physics_properties] has not been advertised, waiting... SpawnModel script started [INFO] [1536553774.571681, 0.000000]: Loading model XML from ros parameter [INFO] [1536553774.576153, 0.000000]: Waiting for service /gazebo/spawn_urdf_model [INFO] [1536553774.577366, 0.000000]: Calling service /gazebo/spawn_urdf_model Service call failed: transport error completing service call: unable to receive data from sender, check sender's logs for details [INFO] [1536553774.728926, 0.000000]: Waiting for service /gazebo/set_model_configuration Segmentation fault (core dumped) [gazebo-1] process has died [pid 24551, exit code 139, cmd /opt/ros/kinetic/lib/gazebo_ros/gzserver -e ode /home/lr101095/tmp/ws2/src/sawyer_simulator/sawyer_gazebo/worlds/sawyer.world __name:=gazebo __log:=/home/lr101095/.ros/log/18c879c0-b4aa-11e8-9b83-f894c21f9c3f/gazebo-1.log]. log file: /home/lr101095/.ros/log/18c879c0-b4aa-11e8-9b83-f894c21f9c3f/gazebo-1*.log cant seem to run the simulation. please see the above for the command line output when trying to use roslaunch sawyer_gazebo sawyer_world.launch Gazebo would load but freeze on a black screen and no model loading. not really sure what to do to fix this. any advice would be much appreciated.
  3. lr101095

    Intera SDK Version

    Just wanted to ask if there's any way i could check what version of Intera i have on my Machine and what version is loaded on the sawyer? Please advise. Cheers, Luke
  4. lr101095

    sawyer inverse kinematics

    Hi Senaa, I was trying to understand the mechanics of the ik_service_client within Intera. For me, i was using endpoint_states as a test input so that i can double check if i'm using ik_service_client correctly since i know what joint states i should be expecting. I also wanted to ask how to subscribe to endpoint_states for a later application. The way you suggested, would that allow me to extract position and quaternion? - Luke
  5. lr101095

    vibrating model

    In addition to this, while trying to update, i got the following: Any suggestions?
  6. lr101095

    vibrating model

    Hi Ian, I've updated as you suggested. However, i'm still seeing unnecessary vibrations in right_j4 when looking at the robot/joint_states/effort through rviz. The vibrations in right_j4 are also affecting the joint torque efforts in right_j3 and right_j6. The consequential vibrations in right_j6 has a negative effect on the application i'm working on, causing inaccurate readings from a force/torque sensor attached to the end-effector of the robot. Is there anything you can suggest that may fix this?
  7. lr101095

    sawyer inverse kinematics

    trying to write a program that subscribes to the endpoint states of sawyer through rostopics. i've opted to subscribe to each individual endpoint_state value. my program is based around ik_service_client, hence why i decided to subscribe to the individual values. I have the following: sub_p1 = rospy.Subscriber("/robot/limb/right/endpoint_state/pose/position/x", String) sub_p2 = rospy.Subscriber("/robot/limb/right/endpoint_state/pose/position/y", String) sub_p3 = rospy.Subscriber("/robot/limb/right/endpoint_state/pose/position/z", String) sub_q1 = rospy.Subscriber("/robot/limb/right/endpoint_state/pose/orientation/x", String) sub_q2 = rospy.Subscriber("/robot/limb/right/endpoint_state/pose/orientation/y", String) sub_q3 = rospy.Subscriber("/robot/limb/right/endpoint_state/pose/orientation/z", String) sub_q0 = rospy.Subscriber("/robot/limb/right/endpoint_state/pose/orientation/w", String) poses = {'right': PoseStamped( header = hdr, pose = Pose( position = Point( x = sub_p1, y = sub_p2, z = sub_p3, ), orientation = Quaternion( x = sub_q1, y = sub_q2, z = sub_q3, w = sub_q0, ), ), ), } However, as a test, i print "poses" and i get the following output: pose: position: x: <rospy.topics.Subscriber object at 0x7fe9f9c31c50> y: <rospy.topics.Subscriber object at 0x7fe9f9c31d50> z: <rospy.topics.Subscriber object at 0x7fe9f9c31d90> orientation: x: <rospy.topics.Subscriber object at 0x7fe9f9bd7050> y: <rospy.topics.Subscriber object at 0x7fe9f9c31e10> z: <rospy.topics.Subscriber object at 0x7fe9f9bd7710> w: <rospy.topics.Subscriber object at 0x7fe9f9bd79d0>} How am i able to print/access the actual data so i have an output of actual numbers that i can then pass on to perform inverse kinematics? I'm not sure if i'm using the correct data type (i.e. String or otherwise) to pass on the values. any corrections, suggestions or solutions would be much appreciated. - Luke
  8. lr101095

    SolvePositionIK and Transformations

    Can someone please explain how SolvePositionIK works in terms of path planning? I want to know how to solve for a trajectory by inputting the point position (and maybe orientation) in order to achieve a desired pose related to the reference point. I'm using a kinect in simulation to scan the environment. So I want to be able to take a point from the camera frame and calculate the position in the global frame so that the transformation required for IK to solve for the pose cam be derived. Can anyone also suggest a way of achieving that? Thanks in advance - Luke
  9. lr101095

    Sawyer Path Planning

    Just wanted to ask if anyone would be able to suggest a method of path planning for sawyer (both in application and in simulation). There is no collision avoidance as of yet and is not yet necessary for what i'm trying to achieve. i just wanted to be able to dictate the path of the robot between two points (initial end-effector location and desired location, including end-effector orientation). I know MoveIt does have a path planner but i'm not sure how to use it. To my understanding, MoveIt is able to plan a trajectory between two poses and execute the calculated trajectory, of course considering joint limits etc. I want to be able to determine a path just by inputting the xyz and normal of a point. For example, I want to be able to move the end-effector to a surface (such as a a table surface) and have the end-effector's z-axis parallel to the normal of surface. Assuming that the xyz (global frame) of the table point is known, i want to be able to control sawyer to move from an arbitrary start point and move to the desired location with the desired orientation. Because of what i need help with, can someone also provide an explanation for how inverse kinematics would work with sawyer? i know there is the IK Service example that involves ik_service_client and SolvePositionIK. But i dont really understand what is going on in that example nor what it does. Any help would be much appreciated. Cheers, Luke
  10. lr101095

    vibrating model

    Hi Ian, I tried to implement what you suggested, but the joints are still vibrating. In addition to that, I am unable to manipulate any of the joints after joint 3 when trying to run my program. Even when i exit the program, i am still unable to move the robot. Before running the program, i am able to use joint_position_keyboard to move the robot. Can you suggest any reason as to why this happens? Regards, Luke
  11. lr101095

    joint angles in simulation

    Hi Ian, I changed the upper and lower limits for joint 6, however now it doesn't seem to make use of the full range. If i use joint_position_keyboard.py, and i try to rotate joint 6, it will only rotate between -4.714 and -1.569. I have the following where you suggested i make the change: <limit effort="9.0" lower="-4.714" upper="4.714" velocity="4.545"/> I haven't changed anything, apart from the lower and upper limit. Any idea why it restricted itself those angles? Regards Luke
  12. lr101095

    joint angles in simulation

    I was comparing the joint angles and joint limits in the simulation and the real robot. I dont think the correct joint angles have been integrated in the simulation. I understand that there may be some variance in the real robot, but i just wanted to make sure i wasn't observing something incorrect. I am trying to run a program, that was written for the real robot, in simulation. It works as expected with the real robot. But there are several discrepancies that i am coming across when running the simulation. One concern is that the joint limits do no match those of the real robot. Because of this, the robot in simulation isn't in the correct pose. For example, in simulation, joint 6 (wrist) has a range of -3.14 to 3.14. The real sawyer has a range of -4.714 to 4.709 in the same joint. I'm not sure if that has anything to do the simulation failing to run the program as expected, but I feel it may because the lack in "flexibility" in the robot in simulation isn't allowing the required pose to be achieved. In the program i'm trying to run, a joint angle of 3.373 is required in the joint 6. Consequently, due to the range provided in the simulation, the required pose in not achieved. it is worth noting that i've only observed this difference in range in joint 6, and i haven't, as of yet, checked to see if there are discrepancies in the other joints. If anyone has any advice regarding how to resolve this, or if there is an upcoming update that resolves this issue, please let me know.
  13. lr101095

    vibrating model

    Hi Ian, I was trying to checkout the kinematics_gravity_torques branch as you suggested, but that branch doesn't seem to exist anymore. The link you provided also doesn't make comparisons between branches anymore. I was able to checkout gravity inertia, but there is still a little bit of vibration from one of the joints. Is there any update regarding the master on git? Cheers, Luke
  14. lr101095

    vibrating model

    While running the sawyer simulation in intera 5.2, i can see that the model is vibrating. Calling rostopic echo robot/limb/right/gravity_compensation_torques, you can see that there are changes being constantly made in actual_position, actual_velocity, actual_effort and gravity_only. I compared the same topic to the real robot, and i saw no changes in the output. Does anyone know why this happens in the simulation or how to resolve it?
  15. lr101095

    vibrating model

    I'm currently running intera 5.2 on my PC and trying to run a sawyer simulation with a force/torque sensor on the end effector. I'm using rqt_plot to get the readings from the f/t sensor. but i'm getting unnecessary noise from the signal even when the sensor is not in contact with anything. (see first screenshot) When i put the f/t sensor to a surface in a static manner (end-effector put towards the surface and kept in contact), the signal is violently oscillating between a max force and 0. (see second screenshot) Zooming into the model of both sawyer and the f/t sensor, i can see that they are both vibrating a little. i can tell because the shadow is oscillating a little bit. I'm posting this question on this forum because i wanted to ask if there have been any changes in the simulation since 5.2.2 was released? i also wanted to ask if anyone was able to resolve this "error"?