Can set friction direction based on link cordinate in URDF

Question

I'm a beginner at gazebo and ROS.

I'm trying to make mobile robot which propels itself using the friction force normal to the direction of wheel.

I want to use cylinder as wheel, and set the friction direction of the cylinder to have a small friction coefficient in the rolling direction and large in normal direction.

I set fdir1 as 1 0 0 in gazebo tag but didn't perform what I desired.

<link name = "wheel">
        <inertial>
            <mass value="${wheel_mass}"/>
            <origin xyz="0 0 0.0" rpy="0 0 0"/> 
            <inertia ixx="${I_wheel_xx}" ixy="0.0" ixz="0.0" iyy="${I_wheel_yy}" iyz="0.0" izz="${I_wheel_zz}"/>
        </inertial>
        <visual>
            <geometry>
                <cylinder radius="${wheel_radius}" length="${wheel_thickness}"/> 
            </geometry>
            <origin xyz="0 0 0.0" rpy="0 0 0"/> 
            <material name = "blue"/>
        </visual>
        <collision>
            <origin xyz="0 0 0.0" rpy="0 0 0"/> 
            <geometry>
                <cylinder radius="${wheel_radius}" length="${wheel_thickness}"/> 
            </geometry>
        </collision>
    </link>
    <gazebo reference="wheel">
        <material>Gazebo/Blue</material>
        <mu>${mu}</mu>
        <mu2>${mu_2}</mu2>
        <fdir>1 0 0</fdir>

So,I want to ask you

1. Is it possible to set the direction of friction in URDF?

2. If it is, how?

3. Is it possible to visualize friction force direction in gazebo or rviz?

Thank you.

Answer 1

I mistakenly used "fdir" instead of "fdir1", fixing it performs what I desired:

<fdir1>1 0 0</fdir1>