Ros::InvalidNameException on negative radian limit value [Closed]

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Hello,

I am at the stage where I can set up moveit and do some motion planning on my custom robot model.

I have executed the moveit setup assistant and specified the URDF with no problems. I generated the package, made it, installed it, etc.

However when I launch the move_group.launch (or the demo.launch as well) I receive this exception:

...: Loading robot model 'Robot_Arm.SLDASM'...
terminate called after throwing an instance of 'ros::InvalidNameException'
what(): Character [-] at element [45] is not valid in Graph Resource Name [/robot_description_planning/joint_limits/Base-Servo2/max_position]. Valid characters are a-z, A-Z, 0-9, / and _.

and then it detects the process has died and I get dumped out.

If I launch the demo.launch, Rviz does load but I get no model shown, and it has an error about NO PLANNING LIBRARY LOADED and there is nothing to select in the dropdown. I have a feeling this may all be related.

This error seems to be because I have set my limits as -x to y radians for my servos. This is necessary I think.

Why doesn't it like negative radian values for limits? And what is the best way to fix this?

I have thought about redesigning my URDF to make servo limits between 0 and 3.1 radians, if it is possible to do this.

<robot
  name="Robot_Arm.SLDASM">
  <link
    name="base_link">
    <inertial>
      <origin
        xyz="0.00071683 0.020356 0.0337"
        rpy="0 0 0" />
      <mass
        value="0" />
      <inertia
        ixx="0"
        ixy="0"
        ixz="0"
        iyy="0"
        iyz="0"
        izz="0" />
    </inertial>
    <visual>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://robot_arm2/meshes/base_link.STL" />
      </geometry>
      <material
        name="">
        <color
          rgba="0.75294 0.75294 0.75294 1" />
      </material>
    </visual>
    <collision>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://robot_arm2/meshes/base_link.STL" />
      </geometry>
    </collision>
  </link>
  <link
    name="Servo2">
    <inertial>
      <origin
        xyz="0.0022691 0.018959 -0.0094813"
        rpy="0 0 0" />
      <mass
        value="0" />
      <inertia
        ixx="0"
        ixy="0"
        ixz="0"
        iyy="0"
        iyz="0"
        izz="0" />
    </inertial>
    <visual>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://robot_arm2/meshes/Servo2.STL" />
      </geometry>
      <material
        name="">
        <color
          rgba="0.75294 0.75294 0.75294 1" />
      </material>
    </visual>
    <collision>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://robot_arm2/meshes/Servo2.STL" />
      </geometry>
    </collision>
  </link>
  <joint
    name="Base-Servo2"
    type="revolute">
    <origin
      xyz="0.00012 0.0001411 0.0744"
      rpy="1.5708 0 0" />
    <parent
      link="base_link" />
    <child
      link="Servo2" />
    <axis
      xyz="0 -1 0" />
    <limit
      lower="-1.5"
      upper="1.5"
      effort="0"
      velocity="0" />
  </joint>
  <link
    name="Upper_Arm">
    <inertial>
      <origin
        xyz="-0.0013475 0.053 9.5019E-16"
        rpy="0 0 0" />
      <mass
        value="0" />
      <inertia
        ixx="0"
        ixy="0"
        ixz="0"
        iyy="1.1301E-05"
        iyz="0"
        izz="0" />
    </inertial>
    <visual>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://robot_arm2/meshes/Upper_Arm.STL" />
      </geometry>
      <material
        name="">
        <color
          rgba="0.75294 0 ...