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2019-12-30 09:18:42 -0600 answered a question wheel rotates, but robot moves slowly

This happened to me recently. The movement of the robot was not smooth, the wheels used to slip. I positioned the caster

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2016-07-05 01:37:55 -0600 asked a question Custom message for publishing 2-dimensional array

Hi,
Can we publish and subscribe to a custom message that contains a 2D-array? Is it necessary that each field type in the must be a message type in gazebo library?
Thanks in advance!

2016-06-29 00:21:33 -0600 commented answer Multiple model plugins for a model

Thanks! I'll try this out.

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2016-06-28 04:19:12 -0600 commented answer Multiple model plugins for a model

How can I get output of 'printf' of each plugin in separate terminal?

2016-06-28 04:02:30 -0600 commented question Multiple model plugins for a model

I tried it. Added one more plugin in the sdf. It worked!

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2016-06-27 07:50:45 -0600 asked a question Multiple model plugins for a model

Hi
Can I have multiple model plugins for a single model?
Thanks in advance!

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2016-01-15 04:59:22 -0600 commented question Custom made robot moves randomly on applying velocity

I've added the links in the question.

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2016-01-14 12:55:59 -0600 asked a question Custom made robot moves randomly on applying velocity

Hi all,

I made a robot(differential drive) which uses meshes as visual and collision elements. Robot executes a small to and fro motion for a small duration when it is inserted. When I apply velocity to one of the hinge joints, the robot moves rapidly; it goes up also. Here is the video. Why this is happening?
Here is sdf file and properties of each link.

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2016-01-10 02:13:24 -0600 commented answer Model moves and rotates when inserted

I've set pose for inertial element of every link. Now the center of masses are at the required positions (almost). But still, the model slips(slightly). Also when some velocity is applied to the hinge joint, the model moves abruptly in the 3D space. Why this is happening ?

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2016-01-09 12:16:10 -0600 answered a question Robot control and physics feedback

Gazebo is an advanced robotic simulation software. You can simulate your biped as your requirements. After making the model you can attach plugins for controlling your robot. Attach sensors to the model for getting its state and make decisions according to it. You can change various physics properties associated with the world too. You may feel difficulties in the beginning but this software will fulfil your needs for simulating the robot.

2016-01-09 11:30:50 -0600 commented answer Model moves and rotates when inserted

Center of mass of every links is located at its origin which are located at a corner of the link( https://drive.google.com/open?id=0B5du_0ymFMtvSXEtcWxiaktFYzg ). Maybe thal causes the problem. How can I make the origin of each link to its original center of mass?

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2016-01-08 00:12:09 -0600 commented answer Model moves and rotates when inserted

The same thing is happening even after disabling the plugin. What are those spheres and boxes indicating?

2016-01-07 07:32:09 -0600 asked a question Model moves and rotates when inserted

Hi all

I made a differential drive robot with meshes for bot collision and visual elements. When it is inserted, the robot keep moving in some direction and rotates in its own axis. Both wheels are also rotating even if velocity is not specified. Sometimes it moves forward and backward.Here are some screenshots and the model directory of the case. Properties of each link can be found here. How these errors can be resolved?

Thanks in advance

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2015-12-20 08:09:40 -0600 answered a question ERROR while accessing joints

I found out the problem. I added the plugin to the model through the world file. I changed it and attached directly in the model.sdf file. Now that error is not coming.

2015-12-19 07:19:34 -0600 marked best answer ERROR while loading world with DiffDrivePlugin as model plugin

Hi there,

I'm trying to control a Pioneer2dx with DiffDrivePlugin. Whenever I start the server, an error occurs. I got the plugin from here. No errors are coming while complilng.
Error:
Error [Element.cc:671] Missing element description for [left_joint]
gzserver: /usr/include/boost/smart_ptr/shared_ptr.hpp:648: typename boost::detail::sp_member_access<t>::type boost::shared_ptr<t>::operator->() const [with T = sdf::Element; typename boost::detail::sp_member_access<t>::type = sdf::Element*]: Assertion `px != 0' failed.
Aborted


What is this error and why this is coming? Can anyone provide me a solution?

Thanks in advance!

2015-12-18 13:30:28 -0600 asked a question ERROR while accessing joints

Hi there,

I was trying to load gazebo with a world file. But it gives following error and exits.

[Err] [Diff.cc:41] Diff plugin missing <left_joint> element
[Err] [Diff.cc:44] Diff plugin missing <right_joint> element
Error [Element.cc:671] Missing element description for [right_joint]
gzserver: /usr/include/boost/smart_ptr/shared_ptr.hpp:648: typename boost::detail::sp_member_access<t>::type boost::shared_ptr<t>::operator->() const [with T = sdf::Element; typename boost::detail::sp_member_access<t>::type = sdf::Element*]: Assertion `px != 0' failed.
Aborted


In the world file I've specified left_element and right_element. Why this is happening?
Also, what is meant by Missing element description for [right_joint]? I didn't find any description for joints anywhere. Can anyone provide a solution for this?

Files:
1. World file
2. Model.sdf
3. Model.config
4. Plugin

Thanks in advance!

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2015-12-17 09:39:42 -0600 answered a question Get Pose of a model from a plugin

I found this method and is working perfectly.

double x,y,z;
gazebo::math::Pose pose;     
pose = this->model->GetWorldPose();
math::Vector3 v(0, 0, 0);
v = pose.pos;
x = v.x; // x coordinate
y = v.y; // y coordinate
z = v.z; // z coordinate
2015-12-17 08:17:27 -0600 asked a question ERROR while loading world with a model plugin

Hi there,

I'm trying to control Pioneer2DX by publishing to topic pioneer2dx/vel_cmd on Gazebo 6.1.0. It is working perfectly but not in the way which I need. The way in which each wheel velocity is found(from OnVelMsg()) is not the way which I need. So, I tried to make a new plugin with the same code of DiffDrivePlugin with different statements in OnVelMsg(). There were no compilation error but when I load the world with the robot, some error is coming.
Here is the error:
Error [Element.cc:671] Missing element description for [left_joint]
gzserver: /usr/include/boost/smart_ptr/shared_ptr.hpp:648: typename boost::detail::sp_member_access<t>::type boost::shared_ptr<t>::operator->() const [with T = sdf::Element; typename boost::detail::sp_member_access<t>::type = sdf::Element*]: Assertion `px != 0' failed.
Aborted

In the world file, I had specified left_ joint and right_ joint in the plugin tag.
Is it because both the DiffDrivePlugin and the plugin I defined are trying to modify/access the same model state? Is there any method to disable the default DiffDrivePlugin attached to the robot?
Here is the world file and plugin file.

Thanks in advance!