EDIT2: I have forked the gazebo\_ros_demos package to try a velocity control on the rrbot simple robot.
Here is the link to my repo:
[https://github.com/Arn-O/gazebo_ros_demos.git](https://github.com/Arn-O/gazebo\_ros\_demos.git)
I have changed something in the configuration files.
VelocityJointInterface and no longer EffortJointInterface:
transmission_interface/SimpleTransmission VelocityJointInterface 1
\velocity_controllers and no longer \effort_controllers:
rrbot:
joint1_position_controller:
type: effort_controllers/JointPositionController
joint: joint1
pid: {p: 100.0, i: 0.01, d: 10.0}
joint2_velocity_controller:
type: velocity_controllers/JointVelocityController
joint: joint2
pid: {p: 100.0, i: 0.01, d: 10.0}
The robot does not explode with this configuration, but I do not have the expected effect. The joint2 is not animated.
EDIT: this is related to the velocity controller. I had another issue before the upgrade, see [answer](http://answers.gazebosim.org/question/4086/fail-to-start/).
Hello.
I have upgraded the source code of the package required for the installation of Gazebo 1.9 and ROS, and now my robot blows up when I launch the controllers. (EDIT: it is fine without the velocity controllers).
Before the controllers:

After:

It looks like everything has collapsed to the origin point of my robot, like if there were no joints.
It was working fine before the update (expect the velocity controller). (EDIT: I had the usse described in the [following answer](http://answers.gazebosim.org/question/4086/fail-to-start/)).
Any idea?
Thx in advance!
EDIT: additional details.
Here is the definition of the elements of my robot related to this topic.
...
...
Definition of the transmission:
...
transmission_interface/SimpleTransmission EffortJointInterface ${wheel_mechanical_reduction}
...
Launch file for the controllers:
...
...
And parameters of the controllers:
youbot:
wheel_joint_fl_velocity_controller:
type: effort_controllers/JointVelocityController
joint: wheel_joint_fl
pid: {p: 100.0, i: 0.01, d: 10.0}
wheel_joint_fr_velocity_controller:
type: effort_controllers/JointVelocityController
joint: wheel_joint_fr
pid: {p: 100.0, i: 0.01, d: 10.0}
wheel_joint_bl_velocity_controller:
type: effort_controllers/JointVelocityController
joint: wheel_joint_bl
pid: {p: 100.0, i: 0.01, d: 10.0}
wheel_joint_br_velocity_controller:
type: effort_controllers/JointVelocityController
joint: wheel_joint_br
pid: {p: 100.0, i: 0.01, d: 10.0}
...
I have no error message when the bug is triggered. I do not know if there is a useful log somewhere.
I can create a simple rrbot like with a velocity controller to investigate the point (the tutorial has been very helpful).
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