<?xml version='1.0' encoding='UTF-8' ?>
<system name="pushback">
 <property>/sim/model/pushback/target-speed-fps</property>
 <channel name="Pushback">

   <switch name="systems/pushback/linked">
     <default value="-1"/>
     <test value="0">
       /sim/model/pushback/position-norm gt 0.95
       /gear/gear/wow == 1
       gear/unit[0]/wheel-speed-fps lt 50
     </test>
   </switch>

   <summer name="systems/pushback/speed-error">
     <input>/sim/model/pushback/target-speed-fps</input>
     <input>-gear/unit[0]/wheel-speed-fps</input>
   </summer>

   <pid name="systems/pushback/force">
     <input>systems/pushback/speed-error</input>
     <kp>/sim/model/pushback/kp</kp>
     <ki>/sim/model/pushback/ki</ki>
     <kd>/sim/model/pushback/kd</kd>
     <trigger>systems/pushback/linked</trigger>
     <output>/sim/model/pushback/force</output>
   </pid>

   <switch name="systems/pushback/force-output">
     <default value="0"/>
     <test value="systems/pushback/force">
       systems/pushback/linked == 0
     </test>
     <output>external_reactions/pushback/magnitude</output>
   </switch>

 </channel>
</system>