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Can you suggest the Gazebo plugin for the Mecanum wheel robot ? Because planar move and ros force based move don't work for me

asked 2019-07-14 05:51:37 -0500

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Hi, I am quite new to ROS and Gazebo. I have try the planar move plugin for my Mecanum robot. It seem to be good except that the this plugin override physics. That means even I change mass, inertia, friction in URDF of my robot. There is no effect. When I move robot 1000 kg or 1 kg it yield the same results. Therefore I use ros force based plugin for my multiple Mecanum robots instead of the planar move. refer to https://answers.ros.org/question/2128...

You can check the ros_force_based_move plugin here

https://github.com/tu-darmstadt-ros-p...

However, I still found a problem here.

  • When I spawn the robot, there are always offset of robot position in my map and also the yaw direction offset for 90 degrees. Hence, I have to edit the arguments for static transform node in order to solve this problem. Here are some parts of my launch file to call a single robot with the namespace.

<node pkg="tf" type="static_transform_publisher" name="odom_map_broadcaster" args="0 0 0 0 0 0 /map $(arg robot_name)/odom 10" />

Note that when I set to 0 0 0 0 0 0 the robot will offset in Rviz when compare to the Gazebo So I have to change the offset here. But when I use the original planar move there is no problem.

  • When I move robot sideways in the y-axis, the odometry in Rviz does not change even though in gazebo it has change position already. For move straight and backward in X-axis, there is no problem.

Here is the part of my URDF file to call the plugin in

<gazebo> <plugin name="ros_force_based_controller" filename="libgazebo_ros_force_based_move.so"> <commandTopic>cmd_vel</commandTopic> <odometryTopic>odom</odometryTopic> <odometryFrame>odom</odometryFrame> <odometryRate>100.0</odometryRate> <robotBaseFrame>base_link</robotBaseFrame> <publishOdometryTf>true</publishOdometryTf> <yaw_velocity_p_gain>500</yaw_velocity_p_gain> <x_velocity_p_gain>1000</x_velocity_p_gain> <y_velocity_p_gain>1000</y_velocity_p_gain> <cmdVelTimeOut>0.25</cmdVelTimeOut> </plugin> </gazebo>

Finally, I have studied from ridgeback robot simulation from Clearpath robotics. It seems that they modify the ros force based move to not publish odometryTF. But they use this information from "gazebo_ros_control" instead. This simulation is work for me. But I can't migrate code to make multiple Mecanum robots. So I still looking for the best solution plugin for my multiple mecanum robot.

The link of Ridgeback robot URDF is here

https://github.com/ridgeback/ridgebac...

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answered 2020-04-01 04:42:10 -0500

gurbain gravatar image

Hi,

I may be a bit late to answer but concerning the problem of measuring the odometry on the y-axis, I think it's because the implementation of the force_move_based_plugin simply ignores it, as we can see in the function computing odometry:

tf::Transform GazeboRosForceBasedMove::getTransformForMotion(double linear_vel_x, double angular_vel, double timeSeconds) const

I think a solution is to reimplement this function correctly by taking the transversal axis into account. I tried to replace it with the following and it looks like it works now but I still have to test it more thoroughly:

    tf::Transform GazeboRosForceBasedMove::getTransformForMotion(double linear_vel_x, double linear_vel_y, double angular_vel, double timeSeconds) const
{

    tf::Transform tmp;
    tmp.setIdentity();

    const double linear_x = linear_vel_x * timeSeconds;
    const double linear_y = linear_vel_y * timeSeconds;
    const double angular = angular_vel * timeSeconds;

    if (std::abs(angular_vel) < 0.0001) {
        tmp.setOrigin(tf::Vector3(linear_x, 0.0, 0.0));
    } else {
        const double delta_x = linear_x*cos(angular) - linear_y*sin(angular);
        const double delta_y = linear_x*sin(angular) + linear_y*cos(angular);

        tmp.setOrigin(tf::Vector3(delta_x, delta_y, 0.0));
        tmp.setRotation(tf::createQuaternionFromYaw(angular));
    }

    return tmp;
}
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Asked: 2019-07-14 05:51:37 -0500

Seen: 609 times

Last updated: Apr 01