Why can't the Controller Spawner find the expected controller_manager ROS interface?

Question

I have a quadruped robot with base link (BL), 4 child links called LFT, LFT, RFT, RFT, T for thigh and each having 4 children with name LFC, LBC, RFC, RBC, C for Calf. 8 joints - Base link to 4 thighs and 4 thighs to 4 calfs are used.

An excerpt from the URDF is posted below:

 <link
    name="LFC">
    <inertial>
      <origin
        xyz="0 -0.085 0" rpy="0 0 0" />
      <mass value="0.038416" />
      <inertia ixx="0.00010326" ixy="0"  ixz="0" iyy="1.3494E-06" iyz="0" izz="0.00010451" />
    </inertial>
    <visual>
      <origin xyz="0 0 0"            rpy="0 0 0" />
      <geometry>
        <mesh filename="package://urdfgenesyssw/meshes/LFC.STL" />
      </geometry>
      <material name=""> <color rgba="0.89804 0.91765 0.92941 1" />
      </material>
    </visual>
    <collision>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry>
        <mesh filename="package://urdfgenesyssw/meshes/LFC.STL" />
      </geometry>
    </collision>
  </link>

A Joint and Transmission sample is also shown:

  <joint    name="LFTLFC"    type="revolute">
<origin      xyz="0 -0.17 0.004"      rpy="0 0 1.5708" />
<parent      link="LFT" />
<child      link="LFC" />
<axis      xyz="0 0 1" />
<limit      lower="-0.7854"      upper="0.7854"      effort="0"      velocity="0" />

  <transmission name="LFTLFC_trans">
<type>transmission_interface/SimpleTransmission</type>
<joint name="LFTLFC">
  <hardwareInterface>EffortJointInterface</hardwareInterface>
</joint>
<actuator name="LFTLFC_motor">
  <hardwareInterface>EffortJointInterface</hardwareInterface>
  <mechanicalReduction>1</mechanicalReduction>
</actuator>

Controllers are as shown below:

  # Publish all joint states -----------------------------------
  joint_state_controller:
    type: "joint_state_controller/JointStateController"
    publish_rate: 50
  # Position Controllers ---------------------------------------
  LFTLFC_controller:
    type: effort_controllers/JointPositionController
    joint: LFTLFC
    pid: {p: 100.0, i: 0.01, d: 10.0}
  /gazebo_ros_control/pid_gains:
    LFTLFC: {p: 100.0, i: 1.0, d: 10.0}

The launch part of the controllers is as follows:

<rosparam command="load" file="$(find urdfgenesyssw)/config/joints.yaml" ns="/urdfgenesyssw" />
<node name="controller_spawner" pkg="controller_manager" type="spawner" respawn="false" output="screen" ns="/urdfgenesyssw" 
args="joint_state_controller
BLLFT_controller
LFTLFC_controller
BLLHT_controller
LHTLHC_controller
BLRFT_controller
RFTRFC_controller
BLRHT_controller
RHTRHC_controller
--timeout 30 " />

Why does the error show:

[WARN] [1592642363.497903, 24.557000]: Controller Spawner couldn't find the expected controller_manager ROS interface.

Answer 1

It is always recommended to mention your ROS distribution and OS. I believe the error is coming from missing ROS package controller_manager. You can download and install it from the following link

https://github.com/ros-controls/ros_control