how get torque of each joint during move in ROS ?

edit

There is the plugin ft_sensor. Here's the snippet in my urdf file:

<xacro:macro name="sensor_force_torque" params="joint_name topic_name">
<gazebo>
  <plugin name="ft_sensor" filename="libgazebo_ros_ft_sensor.so">
    <updateRate>100.0</updateRate>
    <topicName>${topic_name}</topicName>
    <jointName>${joint_name}</jointName>
  </plugin>
</gazebo>

</xacro:macro>

That's a macro so for creating instances it would be:

<xacro:sensor_force_torque joint_name="leg_1_joint_1"  topic_name="robot/leg_1_joint_ft_1"/>

I do get readings but I have not evaluated them properly but should give you a head start.