I'm trying to publish a JoinTrajectory message to move a robot arm in Gazebo. When i type roslaunch mypackage myfile.launch i don't have error but the robot doesn't move (it appears in Gazebo but it is stuck). What I forgot? These are my file (script,launch and yaml), the urdf is provided by Denso:

#! /usr/bin/env python
import rospy
from trajectory_msgs.msg import JointTrajectory
from trajectory_msgs.msg import JointTrajectoryPoint

rospy.init_node('trajectory')
pub = rospy.Publisher('/vs060/arm_controller/command',JointTrajectory,queue_size=1)
trajectory=JointTrajectory()
point=JointTrajectoryPoint()
trajectory.header.stamp=rospy.Time.now()
trajectory.header.frame_id = "/base_link";

trajectory.joint_names.append("joint_1");
trajectory.joint_names.append("joint_2");
trajectory.joint_names.append("joint_3");
trajectory.joint_names.append("joint_4");
trajectory.joint_names.append("joint_5");
trajectory.joint_names.append("joint_6");

point.positions.append(0.0)
point.positions.append(0.0)
point.positions.append(0.3)
point.positions.append(0.6)
point.positions.append(0.5)
point.positions.append(10.0)

trajectory.points.append(point)
pub.publish(trajectory)

I created also this launch file to load robot model, to launch the nodes, the controllers:

<launch>
  <!-- This launch file will start gazebo with a robot model (by default the vs060) -->
  <!-- Override robot_name argument to load a different robot -->
  <arg name="robot_name" default="vs060" />

  <!-- Robot description argument -->
  <arg name="robot_description" value="$(arg robot_name)_description" />

  <!-- include the empty world to launch gazebo -->
  <include file="$(find gazebo_ros)/launch/empty_world.launch">
    <arg name="world_name" value="$(find denso_robot_gazebo)/worlds/denso_robot.world"/>
  </include>

  <!-- Load the URDF, SRDF and other .yaml configuration files on the param server -->
  <param name="robot_description" type="str" textfile="$(find denso_robot_descriptions)/$(arg robot_description)/$(arg robot_name).urdf"/>

  <!-- $(arg gui) evaluates to the value specified by an <arg> tag. There must be a corresponding <arg> tag in the same launch file that declares the arg. -->
  <arg name="gui" default="true"/>
  <param name="use_gui" value="$(arg gui)"/> 

  <!-- launch the spawn_urdf node using spawn_model from the gazebo_ros package with some arguments -->
  <node name="spawn_urdf" pkg="gazebo_ros" type="spawn_model" args="-param robot_description -urdf -model $(arg robot_name)" />

  <!-- To load the controller -->
  <rosparam file="$(find denso_robot_descriptions)/$(arg robot_description)/denso_robot_control.yaml" command="load" />

  <!-- Launch the controller_spawner node from controller_manager using spawner executable, if it dies it doesn't respawn, the node starts in the namespace provided by the robot_name argument-->
  <node name="controller_spawner" pkg="controller_manager" type="spawner" respawn="false" output="screen"
   ns="/$(arg robot_name)" args="joint_state_controller arm_controller" />

  <node name="robot_state_publisher" pkg="robot_state_publisher" 
        type="robot_state_publisher" respawn="false" output="screen">
    <!-- Remap let you launch the same node under multiple configurations from the command-line. -->
    <remap from="/joint_states" to="/$(arg robot_name)/joint_states" />
  </node>
  <node name="trajectory" pkg="vs060robot" type="trajectory.py" output="screen">
  </node>
</launch>

And this is the .yaml file:

vs060:
  joint_state_controller:
    type: joint_state_controller/JointStateController
    publish_rate: 125  

  arm_controller:
    type: "position_controllers/JointTrajectoryController"
    joints:
      - joint_1
      - joint_2
      - joint_3
      - joint_4
      - joint_5
      - joint_6