rsmitha's profile - activity

Hi,

I am using the jackal for my university project.

I have attached a camera to collect images and am using the cv bridge library to get snapshots. On the desktop and simulation environment, I use the same camera and cv::bridge. I am able to see the images that are being captured because cv::window works.

I use ssh to log into the jackal and run my program. Is there a way to make sure that the images are being taken and they are what I think they are?

For example, is there a way that I can enable the gui of the cv brigdge on the jackal and use CV window to see the images being taken and processed?

Please advise. Need help. Regards, rsmitha.

Hi,

I am running a simulation with jackal. I am performing some tests where I ask the jackal to run a certain distance, stop and return to (0,0). When I try to set the pose of the jackal in the odometry frame to (0,0), using /set_pose, the pose does not get reset. For example, after the robot moves for a distance of 10m, the position is (10.503, -0.0001). I want to have the robot's odometry position to be (0,0) and starting counting is position again from (0,0).

In other words, I want to be able to erase the sensor data from the odometry source in ROS for each run, so that for every run it can start as it does at startup. Is that possible through some parameters?

Please help. Regards, rsmitha.

Hi,

I am using the jackal in simulation. I am performing a few tests and collecting data.

My program drives the robot with steady increase in speed such that the increment itself is increased by a random value for every iteration every 100ms till a speed of 2m/s has been reached. This is to obtain increasing acceleration till 2m/s.

The robot then drives for 5 seconds at the constant linear speed after which the speed is ramped down at the same rate of 0.01m/s every 100ms.

During this test, I collect the linear acceleration data from the /imu/data topic. I expected the acceleration to go up with with the linear speed till the constant value of 2m/s is reached after which the acceleration should drop to zero.

However, when I check the linear_acceleration.x data from imu, the values seem to be almost constant. It seems as if the acceleration is not happening.

Is there something I am missing with respect to the imu? I have pasted the basic launch file which I am using. There have been no changes made to the launch file which is used as available from the jackal software package.

<launch>
<arg name="use_sim_time" default="true" />
<arg name="gui" default="true" />
<arg name="headless" default="false" />
<arg name="world_name" default="$(find jackal_gazebo)/worlds/jackal_race.world" />

<!-- Short-term hack to support the original front_laser:=true argument for spawning
      the simulator. This will be removed in favour of using the config:=x arg instead. -->
<arg name="front_laser" default="false" />
<arg name="default_config" value="front_laser" if="$(arg front_laser)" />
<arg name="default_config" value="base" unless="$(arg front_laser)" /> 
<!-- end of hack -->
<!-- Configuration of Jackal which you would like to simulate.
      See jackal_description for details. -->
<arg name="config" default="$(arg default_config)" />
<!-- Launch Gazebo with the specified world -->
<include file="$(find gazebo_ros)/launch/empty_world.launch">
<arg name="debug" value="0" />
<arg name="gui" value="$(arg gui)" />
<arg name="use_sim_time" value="$(arg use_sim_time)" />
<arg name="headless" value="$(arg headless)" />
<arg name="world_name" value="$(arg world_name)" /> 
<!-- <arg name="world_name" default="worlds/empty.world"/> -->
</include>
<!-- Load Jackal's description, controllers, and teleop nodes. -->
<include file="$(find jackal_description)/launch/description.launch">
<arg name="config" value="$(arg config)" />
</include>
<include file="$(find jackal_control)/launch/control.launch" />
<include file="$(find jackal_control)/launch/teleop.launch">
<arg name="joystick" value="false"/>
</include>
<!-- Spawn Jackal -->
<node name="urdf_spawner" pkg="gazebo_ros" type="spawn_model"
      args="-urdf -model jackal -param robot_description -x 0 -y 0 -z 1.0" />
</launch>

Please help.

Regards, rsmitha.

Unable to display image with cvbridge Hi, I am reading an image using the cv-bridge API with ROS and I just want to dis

Hi @Wolf, Sorry for delay. I was able to check this today: Here is the header information:header: seq: 95 stamp:

Hi @Wolf, Sorry for delay. I was able to check this today: Here is the header information:header: seq: 95 stamp:

Hi,

I have run some tests using the jackal and ros indigo. I collected the "x,y,z,w" values for the orientation from the wheel based odometry. These are quaternion representations of the orientation of the jackal.

Similar values are printed for the IMU as well. Here are some values which I logged:

//odometry orientation
[ INFO] [1524638957.013930930]:robotorn:x,y,z,w=0.000000,0.000000,0.037674,0.999290 

 //Imu orientation
[ INFO] [1524638957.013949804]:robotimu:x,y,z=0.000690,-0.000165,-0.987262

Why are the IMU values negative as compared to those of the odometry? Which should we consider while making our calculations?

Regards, rsmitha.

Hi @Delb, thanks for the visualisation link. Its great. If I have just the x,y,z values for the imu orientation and I wi

Hi.@stevejp, I am using the onboard imu.

Hi @Delb, I am comparing quaternions for odometry and imu. I did not capture the'w' value for the imu as I forgot to add

Orientation from wheel based odometry vs IMU Hi, I have run some tests using the jackal and ros indigo. I collected the

Orientation from wheel based odometry vs IMU Hi, I have run some tests using the jackal and ros indigo. I collected the

Hi @Wolf, Thanks for the suggestion. I will try this out and post a comment.

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point grey camera withe jackal Hi, I am using the jackal for my university project. I have attached a camera to collec

If you just trying to use PoseWithCovarianceStamped, you should be able to subscribe to it and get your odom data. That

I was not using the fused data from ekf_localisation/robot_localisation packages. The idea was for me to be just able t

I was not using the fused data from ekf_localisation/robot_localisation packages. The idea was for me to be just able t