Alan's profile - activity

I will give this a try, but I will need to generate a pose as well.

I see, but is there any particular one you can suggest and popularly used with ROS?. Thanks.

Hi, I'm Using ROS for autonomous robotic arms, and the next stage is identifying Barcode on boxes/objects with use of data base capability. I have followed previous tutorials using AR code which works and I'm able to to get ar_pose of the object, which then I can use to grasp object. Can anyone suggest me a similar package but with Barcode?

Many Thanks.

Yes, I will

I already got the Bumblebee 2 running with camera1395stereo driver, however I decide to compare this with the pointgrey_camera_driver and I cant seem to get it working. The first issue was the camera was only detected under root access, and when running camera.launch everything works fine and i can get image feed. However when trying to run bumblebee.launch i get the following error:

[ERROR] [1431072377.545247089]: Reconfigure Callback failed with error: PointGreyCamera::setFormat7 Error validating Format 7 settings | FlyCapture2::ErrorType 22Error setting Format 7 information.

*** Error in/opt/ros/indigo/lib/nodelet/nodelet': free(): invalid size: 0x00007f51cc0a45d0 *`

Which as it indicates is a configuration issue which I cant seem to resolve any one got idea? or experienced this before? PS. besides what are the advantages of using pointgrey_camera_driver over camera1395stereo??

Thanks.

velocity graph for AX-18. Velocity for MX-106. This compares servo movement by using direct rostopic command against MoveIt commander. Thanks for the help

Yes is slightly confusing. Anyway I got MoveIt working using your URDF example with my servos (AX-18 and MX-106). And now it is clearly the problem i'm having with jitter is related with MoveIt. Please if you have time look at those two images below to compare velocity changes.

I have followed your example code using dynamixel_controller, and this resolved the jitter i used to get with Arbotix_controller. However I can only execute commands manually via rostopic pub -1 /joint_name/command...... Cant seem to get it working with MoveIt as i get controller handel error

Been following the code and example you sent me, I dont think my issue is related to the weight of the arm, because i had the same problem without any load or arm (servo alone) I think is to do with the controller driver (Arbotix), I will maybe try Dynamixel_driver again to verify.

Thanks for the suggestion, I will have a try and let you know.

Hi All,

I have got a slight problem getting the MX-106T Dynamixel to move smoothly while using ROS and MoveIt. I'm using Arbotix driver with USB2Dynamixel controller. I can get the arm moving, planning and moving as intended, in fact it is working perfectly when using default controller max_speed of (702) via the YAML file max_speed702. However when I reduce the velocity via either controller YAML or the Joint_limits (when using moveIt) the motion is no longer smooth and occasionally spikes during command execution either via direct rostopic pub or using moveIt commander max_speed:60.

So the problem is probably the Arbotix, however if I set the max_speed back to 702 then launch the controller and use the following command

rosservice call /joint_name/set_speed 0.3

Then executing the motion command will be make the arm move slower and perfectly smooth as shown in the image set_speed 0.3. At this point all motion are no longer jerky but another problem arises in moveIt where the robot always collide with the given constraint. So my question is where is the issue of this jerky motion in first place and why would the manual set_speed solves that motion but also introduce a problem of its own.

YAML file for controller, which I have modified the rate/ and write_rate few times to avoid common jerky movement.

port: /dev/ttyUSB0
baud: 200000
rate: 300
sync_write: True
sync_read: False
read_rate: 60
write_rate: 60
joints: {
  wrist_flex_joint: {type: dynamixel, id: 4, ticks: 4096, neutral: 2048, range: 360, min_angle: -111, max_angle: 111, max_speed: 702},
  sholder_pan_joint: {type: dynamixel, id: 1, ticks: 4096, neutral: 2048, range: 360, min_angle: -180, max_angle: 180, max_speed: 702, invert: true},
  elbow_lift_joint: {type: dynamixel, id: 2, ticks: 4096, neutral: 2048, range: 360, min_angle: -90, max_angle: 90, max_speed: 702},
  l_gripper_joint: {type: dynamixel, id: 5, max_speed: 15, invert: false},
  r_gripper_joint: {type: dynamixel, id: 6, max_speed: 15}
}
controllers: {
 arm_controller: {onboard: False, action_name: arm_controller/follow_joint_trajectory, type: follow_controller, joints: [sholder_pan_joint, elbow_lift_joint, wrist_flex_joint]}
   }
imu: true

Any one had this issue or understands this problem, please let me know I have tried few things and this is not making any sense any more.

Many thanks,

Alan

Hi all,

Any one can advice me, the ideal required sensors for pick and place application using a robotic manipulator with ROS support. I have generally looked at things like Kinect and stereo cameras (Bumblebee2) which provide depth that can be used with PCL for object recognition and gripper positioning. Are there any other sensors would be preferred for such application and if not what are the drawbacks of stereo cameras in comparison to Kinect or other sensing capability.