<handle name="name" clearance="value" approaching_direction="0 0 1">
  <!-- name and clearance are required, approaching_direction is optional -->
    <!-- One of the following position tag. Attributes are optional and read only if the tag has no text. -->
    <position>0 0 0 1 0 0 0</position>
    <position xyz="0 0 0" rpy="0 0 0"/>
    <position xyz="0 0 0" wxyz="1 0 0 0"/>
    <position xyz="0 0 0" xyzw="0 0 0 1"/>
    <!-- the position represents the position of the handle relatively to the following link -->
    <link name="link_name" />
    <!-- Optionally, one may specify a mask.
         It is a sequence of 6 booleans corresponding to the 3 translations
         followed by the 3 rotations. True means the axis is constrained.
         -->
    <mask>1 1 1 0 0 0</mask>
</handle>
