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2015-11-23 03:44:50 -0500 commented question Laser scan to point cloud

You can do a quick

rosrun tf view_frames
evince pdf

to get the frames being published by your laser node.

2015-11-23 03:43:53 -0500 commented question Laser scan to point cloud

Are you sure the frame ID on which the laser publishes the laser scan is called "laser"?

2015-11-23 03:40:08 -0500 answered a question turtlebot bad gyro calibration

Remove the power distribution circuit board from your CREATE Base. On a full battery charge, ensure that there is a constant 5V power supply between pins 8 and 14, as shown in the photo.

image description

If there isn't you'll have to use an external gyro or maybe change the base.

2015-10-26 21:54:30 -0500 commented question Editing gyro_measurement_range in CREATE Turtlebot?

Also, using rosparam set doesn't change the value, since it isn't dynamically reconfiguring the bot.

2015-10-26 21:52:50 -0500 answered a question Registered depth image from Kinect using openni is all zeros (Indigo)

You should try freenect, it worked for me.

 roslaunch freenect_launch freenect.launch

If the error was resolved, how did you do it? Please post.

2015-10-26 21:45:06 -0500 asked a question Editing gyro_measurement_range in CREATE Turtlebot?

After several problems with the CREATE base gyro, I decided to use a SpartonCompassIMU (AHRS-8) for gmapping and pose estimation. I am using a ROS driver available from github. The driver is perfectly fine, and publishes data to /imu/data. I remapped the topics in the minimal, gmapping and calibration launch files and using rosgraph and rosnode/rostopic info, I can conclude that robot_pose_ekf is using the imu/data from SpartonCompassIMU. However, the mapping is still off and the rotational motions are still inaccurate.

I have tried changing the mapping parameters as well, done the laser scan checks in RViz. Not much there. I realized later that for calibration, the gyro_measurement_range is still set to 250 (from the old inactive gyro). I have tried changing that in the config files, but it doesn't seem to be helping much. From the pdf manuals, SpartonCompassIMU, the gyro_measurement_range seems to be 480deg/s.

What am I missing? Where should I be changing the parameter?

2015-10-20 22:37:10 -0500 commented question Turtlebot doesn't walk in a straight line

create. I have calibrated multiple times as well, converging to stable values for correction factors. Still it drifts away towards the left when I command it to move straight

2015-10-19 05:48:27 -0500 commented answer turtlebot imu installation

How would you do the same for a Create base?

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2015-10-16 01:35:20 -0500 answered a question unable to calibration Odometry and Gyro

I am getting the same error as well. How did you solve it, if you did?

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2015-10-14 02:13:21 -0500 answered a question What should I expect from Turtlebot calibration? / How do I know if my Turtlebot is broken?

The CREATE base on the earlier versions of turtlebot has some drawbacks when it comes to hardware (IMU and Battery). If the Ni-Mh battery is old and used over many charging cycles, it will tend to create power fluctuations in your power distribution board. You will need to do a power reset (switch off, unplug cables from turtlebot, remove battery, press and hold power button for a few seconds, connect battery, plug in cables and then turn on).

Moreover, the IMU used is a cheap odometry estimation gyro, which is not reliable for mapping complicated environments (few features, many turns). The calibration process done on a clean power supply can still give you values close to each other, if done multiple times, however, it does not converge to a precise particular value for which the delta yaw (heading error) is close to zero.

In the calibration process, the turtlebot is supposed to rotate 720 degrees first, followed by three 360 degree rotations at varying speeds. It is supposed to point at the wall, or the configuration at which you started the calibration. If this doesn't happen, try changing your odom parameters using rqt_reconfigure.

There is no documented calibration routine, hence it is hard to guess how the gyro_correction factor and the odom_angular_correction factor change the calibration routine.

If you are facing trouble over a long time, you can do the following: 1. Check pin out at the power distribution. Between pins 8 and 14, a steady 5V DC should be present when powered on. 2. Change battery, or get an alternative LiPo power supply (4 cell battery with higher mAh would do) 3. Use a custom IMU 4. Get a kobuki base. It is fairly accurate and factory calibrated.

2015-10-01 21:08:34 -0500 commented answer [solved] Couldn't open Joystick /dev/input/js0

The problem is solved actually. The problem was that I had not set ROS_IP on my remote machine, so a lot of applications that come later in the tutorials after teleop wouldn't open on my PC (like gmapping and rviz).

Thanks for all your help. I'm still a newbie and have a long way to go with ROS!

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2015-09-30 21:37:43 -0500 commented answer [solved] Couldn't open Joystick /dev/input/js0

The joystick works fine when connected to the turtlebot netbook. It won't work in teleop from my remote PC.

I have tried all the troubleshooting steps from that documentation page, with no help.

2015-09-30 21:32:46 -0500 commented answer [solved] Couldn't open Joystick /dev/input/js0

the ls command shows js0. Even jstest gives the required response with all the keys working.

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2015-09-30 07:06:53 -0500 asked a question [solved] Couldn't open Joystick /dev/input/js0

I am trying to "teleop" my turtlebot using a Logitech Attack 3 joystick. I bring up the turtlebot from a remote PC, followed by the command:

roslaunch turtlebot_teleop myjoystick.launch

where myjoystick.launch is the modified logitech.launch file with the added axis_deadman param. The terminal on my remote PC shows error "Couldn't open Joystick /dev/input/js0. Will retry every second." No response when joystick is connected to the remote PC. The turtlebot responds properly when I connect the joystick to the turtlebot netbook.

I tried changing permissions of /dev/input/js0 to 777 as well, with no help.

Also, keyboard teleop happens without any errors.

Why is the remote joystick teleop not happening and how do I fix this?